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Fender design is a complex subject. We therefore take it in small bites and explain selected cases for you in detail in this section: FENDERS - BEST PRACTICE EXAMPLES
Learn more about rubber compound, fender testing, load cases, maintenance, and get tips from a fender expert. Enjoy ⤵️
One thing that has not changed between ???????????????? and ????????????????????, the PIANC Fender Design Guidelines : Mainly ???????????????????? ???????????????????????????????????????????????? ???????????????????????????? are not included or considered part of the guidelines.
????
Solid fenders—like ????-???????????????????????? and ???????????????????????????????? ???????????????????????????????? —are still not covered by these guidelines.
???? ???????????????????? ???????????????????????????????????????????????? ????????. ???????????????????????? ????????????????????????????????????
Solid fenders, such as D-fenders, are designed to mainly transmit forces directly to the structure. They are great for certain applications, but they do not absorb energy the way the guidelines focus on. That is why these types of fenders do not fall within the scope of WG 211, which is centered around high energy-absorbing systems.
⚠️ ???????????????? ???????????????? ???????????????? ???????????????? ???????????? ???????????????? ?????????????????????????????
Solid fenders’ detailed design specs should not include the reference to PIANC . The exception comes with small vessels, where D-fenders can be designed for energy absorption, but that is the rare situation.
???? ???????????????????? ????????????????????????????????:
For projects involving solid fenders, ????????????????????????-???????????????????? ???????????????? ???????????????????????? ???????????????? ???????????????? ???????????????????????????????????????????? ???????????????????????????????????????????????????? to avoid confusion down the line. At ShibataFenderTeam, we can help you sort through the details and ensure your designs match the right guidelines for the right fender system.
#PIANC #WG211 #FenderDesign #MarineEngineering #HolisticApproach
The fender system is not an isolated component, it forms part of the larger quay wall design and so the quay wall or mounting area must be properly sized to support the fender system.
➡️ If the substructure is ???????????? ???????????????????? for proper coverage, the fender will not be able to compensate that.
➡️ If the substructure ???????????????????? ???????????????????? for components like chains, the fender design cannot make up for that either.
⚠️ ???????????????????????????????????????????????????? ???????????? ???????????????????????????????? ???????????????????????????????????????? .
For existing structures, modifications to the substructure are often necessary to properly install a new fender system. Simply placing a fender on an existing layout can cause design problems, like mounting the rubber unit on the upper 1/3 or the panel, impacting functionality, performance and life cycle.
???? Selecting the right fender or adjusting the substructure requires ???????????????? ???????????????? ???????????????? ???????????????????????????????????? ???????????????????????????????????? . Drawing from experience on projects around the world, we provide the insights necessary to make sure everything integrates seamlessly on your site.
Insights from PIANC Fender Guidelines
How to Read the New PIANC Guidelines
Existing Structures
The Real World Impact
Navigation Conditions
The PIANC Fender Design Guidelines (Chapter 2 – Section 2: “Fender Types and Systems”) emphasize the ???????????????? ???????????? ???????????????????????????????????? ???????? ???????????????????????? ???? ???????????????????? ???????? ???????????????????????? ???????????????????????????????????????? ???????????? ???????????????????????????????? ????????????????????, ensuring the fender system meets the project’s unique requirements.
Too often, specifications pick values from a single manufacturer. However, manufacturers have slightly different values, which may lead to selecting a fender size or specification that is only available from one supplier, limiting design options, flexibility, and sole sourcing from one company.
???????????????????????????? ???????????? ???????????? ???? ????????????-????????????????-????????????????-???????????? ????????????????????????????????.
The most efficient fender is not always the best fit for your project and design. Therefore, several different fender types need to be checked to meet the project requirements, like stand-off or matching the available installation area.
???? ???????????????????? ???????????????????????????????????????? ???????????????????????????????????? ????????????????????.
While convenient, they often result in generic designs that overlook critical site-specific details, leading to a fender system that is not customized to the project needs.
???? ???????????????????? ???????????????? ????????????????????????????????.
Relying on a single manufacturer limits options and flexibility. To ensure optimal performance, always consider at least ???????????????????? ???????????????????????????????????? to maintain a flexible design and more suitable choices.
Take the time to evaluate all factors and trust the expert guidance of #TruePartner to select the right fender system that aligns with your project’s requirements.
Navigating the new PIANC Fender Design Guidelines is easy when you know how-to. Here is how you can make the most of it:
The guidelines provide a step-by-step design process, clearly outlining the key stages needed for an efficient fender system, and emphasize the importance of consulting multiple input sources such as rubber specifications, vessel design data, and more—crucial to designing a system that works in real-world conditions. But it does not stop there ↩️↩️
???? ????????????????-???????????????????????????????? ???????????????????????????????????????????? ???????? ????????????
The guidelines also recommend incorporating site-specific information like local building codes, velocities, and berthing angles to ensure the design is right for the project’s unique conditions. You will need to integrate local knowledge to truly optimize your design.
???? ???? ????????????????????????????????????, ???????????? ???? ????????????????
While it offers comprehensive steps and requirements, you have the flexibility to adjust the design based on your expertise and local conditions—provided you have valid reasons for doing so.
In short: The ???????????????????? ???????????????????????????????????????? ???????????????? offer a structured framework for building robust systems, but local knowledge and the designer’s professional judgment are key to ensuring the design is truly optimized for the specific project.
???? ???????????????? ???????????????????????????????? ???????????? ???????????????????????????????????????? ???????? ???????????????? ????????????????????????????’???? ????????????????????????????????????, ???????????????????? ????????????????????????????????????????????????????????????????????. We bring extensive and local experience working with a wide range of port structures, helping engineers and designers customize their fender systems with precision and confidence.
???? ???????????????????????? ???????????????????? ???????????? ????????????????????-????????????????????????????????????????????
The guidelines provide a step-by-step design process, clearly outlining the key stages needed for an efficient fender system. However, to fully understand and apply these steps, you will need to reference multiple chapters. The introduction gives a good overview, but each chapter brings in critical input sources and specific requirements that could influence your design.
???? ???????????????? ???????????? ???????????????????? ???????????????? ???????????????????????????????? ????????????????????????????
The guidelines emphasize the importance of consulting multiple input sources such as rubber specifications, vessel design data, and more—crucial to designing a system that works in real-world conditions.
➡️ ???????????? ???????? ???????????????? ???????????? ???????????????? ???????????????????? ⬅️ Stay tuned for more to come about how to read the new PIANC Fender Guidelines .
???? ???????????????? ???????????????????????????????? ???????????? ???????????????????????????????????????? ???????? ???????????????? ????????????????????????????’???? ????????????????????????????????????, ???????????????????? ????????????????????????????????????????????????????????????????????. We bring extensive and local experience working with a wide range of port structures, helping engineers and designers customize their fender systems with precision and confidence.
The new PIANC Fender Design Guidelines (???????? ????????????) introduce changes that might be challenging for ???????????????????????????????? structures. Here is what that means for your design process:
???? The new guidelines and their design approach are meant for new structures, therefore when applying the often-higher forces of WG211 to existing structures, that could lead to theoretical failures of those substructures.
???? What does this mean for you?
For existing structures, it is essential to ???????????????????????????????????????? your safety and fender correction factors, as the guidelines may be too conservative in their approach. The design should be focused on operational limits, as well as the experience with currently installed fender systems and the typical safety and correction factors applied in previous projects.
In short: ???????? ???????? ???????????? ???? ???????????????????????? ???????? ???????????????????????? ???????????????????????????????? ???????????? ???????????? ????????????????????????????????????????. Existing structures demand a ???????????????? ???????????????????????????????? ???????????????????????????????? ???????????????? ???????????? ????????????????????????????????’???? ???????????????? ????????????????????????????????????.
Need help navigating these changes? At ShibataFenderTeam, we bring years of experience across a wide range of new builds and refurbishment projects. Our direct involvement in the development of the new guidelines gives us unique insight into how to apply them effectively to your specific needs.
???????????????????????????????? ???????? ???????? ????????????’???? ???????????????? ???????????????????????????????? ???????? ???????????????? ???????????????? ???????????? ???????????? ????????????????????????????????????????.
More insights from PIANC Fender Guidelines ⤵️⤵️
In previous posts, we explored Navigation Conditions and Consequence Classes and how they impact the design of fender systems. Together, they form a foundation for the selection of the ???????????????????????????? ???????????????????????? ????????????????????????—a multiplying factor that determines how much safety margin is included in the energy that is absorbed by the fender system during vessel impact
But here's the interesting part: The Partial Energy Factor ???????????? ???????????????? ???????? ???????? ???????????????? ???????? ????????% depending on the combination of these conditions. Let’s break it down in three simple examples :
While the difference might seem small at first, the Partial Energy Factor ???????????????????????????????? ???????????????????????????? ???????????? ???????????????? ????????????, ???????????????? ???????? ???????????????????????? ????????????????????????, ???????? ???????????????? ???????? ???????????? ???????????????????????????????? ???????? ???????????? ???????????????????????????????????????? ???????????????????????????????????????? needed to withstand the applicable forces. The multiplying effect of the Partial Energy Factor means, we’re facing ???????????????????????? ???????????????????????? ???????????? ???????????????????????? ????????????????????, as well as ????????????????????????????????, ???????????????? ???????????????????????????????????? ???????????????????????????????????????? ????????????????????????????????????????.
Numbers are eye-catching, but their real impact lies in how they influence the design to ensure ???????????????????????????? ????????????????????????????????????????????, ????????????????????????, and ????????????????-????????????????????????????????????????.
Now, the real question is not just about determining the factor but to ensure the fender system has the right-sized for the conditions, but also: ???????????? ???????????? ???????????? ???????????????????????????????? ???????? ???????????????????? ???????????? ???????????????????????????? ???????????????? ???????????????????????????????????????????? ???????????? ???????????????????????? ???????????????? ???????????????????????? ???????? ???????????????????????????????? ???????? ???????????????????????? ???????????? ???????????????????? ???????????????????????? ???????? ???????????????????????? ???????????? ???????????????????? ???????????????????????????????????????????? ???????????????????????????????????? ???????????? ???????????????????????? ???????????????????? ???????? ????????????????❓
????????????’???? ???????????????????????????? ???????????? ???????????????? ???????????????????? ???????????????? ???????? ???????????????????????????? ???????????? ???????????????? ???????? ???????????? ???????????????????????????? ???????? ???????????????????????? ???????????????????????? ????????????????????????.
In April , the new ???????????????????? ???????????????????????? ???????????????????????? ???????????????????????????????????????? ???????????????? ???????? ???????????? replaced the old WG 33 version. But here is the catch: Updating your specifications is NOT as simple as swopping out a number.
???? ???????????? ????????????’???? ???????????????? ???????????????????????? "WG33" to "WG211" and call it a day. Why? Because the new guidelines bring a ???????????????????????????????????? ???????????????????????? ????????????????????????????????.
What does that mean in practical terms?
▪️New specifications are needed—completely rewritten.
▪️Local conditions that were not in the old guidelines now play a major role.
▪️The design approach has shifted, so your references need to be updated—not just swopped.
In short: ????????’???? ???????????? ???? ???????????????????????? ???????? ???? ???????????????????????? ????????????????????????.
So, what is your next step? Do not just update. ????????????????????????. Take a fresh look at your specifications. The new guidelines bring a #HolisticApproach to design, which demands more than just a number change.
???? Need guidance? As pioneers in the holistic approach to fender system design, we can offer valuable insights into WG211. With our direct involvement in the development of these guidelines and years of experience, we can help ensure your specifications are fully aligned with the latest standards. ???????????????????????????? ???????? ???????? ????????????'???? ???????????????? ???????? ???????????????????????????? ???????????? ???????? ???????????? ???????????????????????? ???????????????? ???????????? ???????????? ????????????????????????????????????????.
https://www.shibata-fender.team/en/contact.html
????️Vessel approach and control
????Wind, waves, and currents
?????????????
Classified as ????????????????????????????????????, ????????????????????????????????, or ????????????????????????????????????????????, the navigation conditions directly affect the needed fender performance. Understanding them is key to designing systems that ensure safety and efficiency in port operations.
???????????????? & ?????????????
The challenge begins early—before design starts. These conditions, along with ???????????????????????????????????????????? ????????????????????????????, should be considered in the early stages of the engineering process, through active discussions with the asset owner.
????????, ➡️ ?????????????⬅️
These conditions ???????????????????????????????????????????????????? ???????????????????????????????????? ???????????????????????????????? ????????????????????????????????, ???????????????????????? ???????????????????????????? ???????????? ????????????????????????. Their impact cannot be overstated in terms of:
???????????? ????????????????????????????????:
Relying on experienced fender design professionals ensures that every system is designed to the highest standards in the marine industry, guaranteeing both safety and optimal performance throughout the system's design life. However, the cooperation and input from the asset owner is of most importance here.
Stay tuned as we continue to unpack key insights from the PIANC Fender Guidelines .
?????????????????
A classification system based on varying risk levels that determines the potential impacts of fender system failure. It significantly influences the #ReliabilityRequirements and serves as a foundation for taking an informed design approach, helping to avoid over- or under-design while optimizing both safety and cost-efficiency.
?????????????
It directly impacts key factors for the Design a fender System
➡️ ???????????????????????? ???????????????????????????????? ????????????????????????
➡️ ???????????????????????? ????????????????????????????????????
W?????????????
Early assessment is crucial for designing a fender system that can withstand berthing forces while remaining aligned with operational goals and constraints.
?????????????
The asset owner (e.g., port authorities or terminal operators) is responsible for defining the Consequence Class, often with expert consultation to ensure the classification accurately reflects the potential impact of system failure.
???????????? ????????????????????????????????
Understanding the position and potential failure consequences of a fender system is crucial, highlighting the importance of properly assessing the Consequence Class and relying on experienced fender design experts.[nbsp
Insights from PIANC Fender Guidelines
Edge Distance
Fender System Design
Shear Compresion Testing
Chain Tensioners
Functional requirements: The core purpose of the fender system
☑️ Operational requirements: During berthing and mooring conditions
☑️ Site conditions: Environmental factors and berth configuration
⚠️ Design Criteria, Return Period, and Design Life
PIANC’s Guidelines emphasize that while fender systems typically have a design life of 20 years, they must be built to handle 50-year return period loads. An under-designed fender won’t provide the needed performance and berthing forces might be introduced directly into the structure. Even if replaced within 20 years, the fender's design must account for the loads it will encounter throughout its lifecycle.
???? Operation and Maintenance
To keep the fender system functional over its service life, a maintenance and inspection plan must be established in the design phase and passed on to the operator for ongoing implementation.
???? Reliability Requirements
The most critical factor in reliability is the consequence class, which impacts energy, safety, and load factors. Selected by the asset owner, this class determines the risk level, with Class A and B being the most common for marine structures.
???? Key takeaway: Designers should focus on fender systems to be customized to the structure’s specific needs, balancing short-term durability with long-term reliability. Avoid creating sole-source specifications, as a similar energy absorption may have varying reaction forces across different manufacturers.
At ShibataFenderTeam, we bring decades of expertise in fender system design, manufacturing, and maintenance. As industry leaders, we support consultancy firms and stakeholders throughout the design process, ensuring reliable, safe solutions for every project.
Building on the designer's role outlined in the PIANC Guidelines, we now examine a crucial aspect: the selection of a fender system. #Chapter6
???? ???????????? ????????????????????????????????: the most efficient energy-absorbing fender may not always be the most suitable for the required application; efficiency alone is insufficient. What truly matters is selecting a fender system customized to the specific conditions of the project.
???? ???????????? ???????????????? ???????????????? ???????????????????????? ? While it might be tempting to choose the fender with the highest energy absorption, such a choice can lead to inefficiencies or even failures if the design does not consider the entire context. The guidelines emphasize that ???????? ???????????? ???????????????????????????????? ???????????????????????????????????????? ???????????? ???????????? ???????? ????????????????-???????????????????????????????? ???????????????????????????????????????????? to ensure the selected fender system meets all necessary requirements. ↩️↩️
“ ???????????? ???????????????????????????????????? ???????? ???? ???????????????????????? ???????????????????????? ???????????????????????????????? ???????? ???????????????? ???????????????????????????????????? ???????? ???????????? ???????????????????????? ???????? ???????????? ???????????????????? ???????????????????????????? ???????? ???????????? ???????????????????????????????????? ???????? ???????????????????? ???????? ???????? ???? ????????????????. ???????????? ???????????????????????????????????? ???????? ???????????? ????????????????????????, ???????????? ???????????????? ???????? ???????????????????????? ????????????????????????, ???????????? ???????????? ???????????????????????????????????????? ???????????????????????? ???????????????????????????????????? ???????????? ... ????????????????????????????????????????????.”
???? Designers:
Chapter 2 of the PIANC Guidelines, "Introduction to the Principles of Fendering," provides essential insights into the complexity of designing efficient fender systems. A key takeaway?
The role of the designer is paramount in navigating these complexities.
???????????????????????????????????? ???????????????? ???????????????????????????????? ???? ???????????????? ???????????????????? ???????? ???????????????????????????? ???????????????? ???????????????????????????????????? ???????????? ???????????????????????????????????? ???????????????????????? ????????????????????????????; ???????? ???????? ???????????? ???????????????? ???????????????????? ????????????????????????????????????????????, ???????? ???????? ???????????????????? ???????????????????????????????????????????? ???????????? ???????????????????????? ???????????????? ???????????? ???????????????????? ???????????????????????????????????? ???????????? ???????????????????????????????????????? ???????????????????????????????????????????? ????????????????????????????????????????????.
???????????? ???????????????? ???????????????? ????????????????????????? Simplified fender selection tools might seem convenient, but they can lead to generic designs that fail to address specific berthing conditions, vessel types, and structural considerations.
⏩The importance of a #HolisticApproach cannot be overstated⏪
K???????? ???????????????????????????????????????????????????????? ???????????? ???????????????????????????????????? – ???????????????????????????? ????.???? ???????????????????????? ???????????????????? ???????????? ???????????????????????????? (???????????????????? ????????-????????):
???????????????????????????????????????? ????????????????????????: The fender system must be designed in combination with the berth structure. Not all fender types are compatible with all structures, so this integration is crucial.
???????????????????????????????????????????????? ???????????????? ????????????????????????????: Collaborating with fender manufacturers during the design phase is essential. Designers are encouraged to incorporate ongoing research and development efforts in fender materials and components to achieve the best outcomes.
???????????????????????????????????? ???????? ????????????????????????????????????????: Performance characteristics can vary between manufacturers, even for similar fender types. This is particularly important when dealing with load-sensitive structures, and designer should check at least 2-3 manufacturers catalogues to avoid sole sourcing for a particular project.
Ultimately, the success of a fender system lies in the designer's ability to navigate these complexities, ensuring that every component is carefully considered and integrated. ⤵️
At ShibataFenderTeam, we have long advocated for a holistic approach that integrates all fender system component’s design—including steel panels, chains, and anchors—along with manufacturing processes and project-specific conditions to ensure the final system design meets the unique demands of each project.
Why standards are important? Standards ensure consistency, reliability, and quality across an industry by setting clear expectations, promoting safety, and building trust.
???????????????????? ???????????????? ???????????????????????????????????????? ????????????????????:
????" The standard orientation of these fenders is for the wider footprint to be connected to the supporting structure and the narrower footprint to be connected to the back of the fender panel."
Additionally, the guidelines caution designers about the non-standard, or inverted, orientation:
????" Inverting a fender can result in a different distribution of stresses, with potential additional stresses induced in certain parts of the fender."
Finite Element (FE) analysis supports this, showing that non-standard orientations can lead to stress distributions, that could impact the fender’s life cycle.
????????????????????????????????????????:
While the non-standard orientation may appear beneficial in specific scenarios, adhering to the standard ensures better durability, reliability, reduced liability for the designer and sustainability in the long run.
???????? ???????????? ???????????? ????????????????????, we:
➡️ championed the standard and sustainable orientation long before PIANC endorsed it
➡️ led the industry by publishing detailed FE analysis on our network and website, exposing the consequences of non-standard orientations
➡️ set the standards, not just followed them, proving our leadership in fender design and best practices
more closeWhen navigating fender system design challenges, the edge distance of the chain brackets and fender anchors ???????? ???? ???????????????????????????? ????????????????????????. This is particularly true for both existing structures and new designs. Why the importance?
In existing structures making modifications can be a complex task, and the importance of edge distance is often overlooked in the design of new structures.
The key to success lies ???????? ???????????????????????????????????? ???????????????????????????????????????????????????? ???????????????? ???????????????????????? ????????????????????????????????????????????????????. Engaging with them early in the design process can yield essential insights into the overall layout of the fender system, including the positioning of chains.
???? Here are our recommendations to consider during the design stage of fender projects:
⛓️ The edge distance is most critical for chain anchors, as they are subject to tension when the fender system is in operation. An inadequate edge distance can lead anchor break-out and damage to the quay wall.
⏪⏩ For the initial layout design, an edge distance of approximately 8-10 times the anchor diameter in all directions is recommended. This serves as a solid starting point for ensuring adequate clearance and system functionality.
↔️ While smaller edge distances are feasible, they require a thorough examination of the quay wall design by the designer. This may include adding extra reinforcement based on the loads, provided by the fender manufacturer.
➕Beyond edge distance, other factors like thickness of the quay wall section at the fender location and the grade of concrete should not be overlooked. These elements are integral to the overall strength and effectiveness of the anchor design.
Imagine a dinner recipe featuring top-tier, organic ingredients, but the recipe lacks balance.
You might leave the restaurant with ???? a less-than-satisfactory dinner experience.
A similar principle holds true for fender system design. Why?
Flawed fender system designs (similar to a recipe) can have significant and costly operational impacts. Even if you have a high-quality, durable rubber unit (resembling an organic ingredient), it cannot compensate for an ⚖️ unbalanced design.
Take, for instance, the layout of chains ????, a crucial aspect not to be underestimated. Have a look at the picture below, you can observe two fender systems – one with chains and one without:
(1)
Incorrect, or in this case, absent chains can lead to various adverse consequences
(2)
The Cone Fender System, on the other hand, has been meticulously designed with weight and tension chains.
A combined shear compression testing is an alternative to a simple compression testing. This durability test combines axial deflection with ???????????????????? ????????????????????????????????????????.
⚠️ Keep in mind that fenders typically experience compression and shear at the same time when being used at the berth. ⚠️
At SFT, the ???????????????????????????????? ???????????????????? ???????????????????????????????????????????? ???????????????? ???????????????????????????????????? allows for almost any fender size to be tested, yet the number of compression cycles is inherently limited for the largest fenders. For scale models, 25,000 and more test cycles are possible and have already been successfully ???????????????????????? ???????????????????? ???????????????? ???????????????? ???????????????????????????????? ????????????????????????????????. Full scale testing with max. 3 cycles is recommended for demanding and sensitive projects.
Ｅｘｐｅｒｔ ａｄｖｉｃｅ：Durability tests could be surprisingly expensive. Before this test protocol is required in specifications, we suggest to consult with the manufacturer for details and prices to be aware of the additional cost.
SFT compiled all the “need-to-know” information about Fender Testing in its ???????????????????? ???????????????????? ‘???????????????????????????? - ???? ????????????????-???????????????????????????????? ????????????????????????????????’
more closeThey are an important tool to tighten chains of a fender system during installation, and also to re-tension them while in service.
This is also valid and important for tension chains, being an essential component of a fender panel system.
Tension chains work in several ways:
① Balance the forces in the fender system and maintains position and alignment of the panel
② Prevent mooring lines being caught behind the panel (when chains being installed at the top of the panel)
③ For a cantilever fender system, prevent collision of the bottom of the panel with the substructure during low level contact
④ Ensures sufficiently compressed fender and the needed energy absorption during low level contact
The location and angle of the chain will affect the fender system’s performance. It is recommended to install the tension chain in a 90° angle to the wharf face, and when used in cantilever fender systems, it should be located at a practical distance above or below the centre-line of the rubber unit.
???? A chain tensioner is always recommended – however – in some projects it is not possible to add it to the chain system, due to geometrical restrictions. Those can be that a chain is very short – and if a chain tensioner was added, the chain would not be able to move flexibly when the fender is compressed.
✔️ A holistic approach to fender system design considers the ???????????????????????????? ???????? ???????????? ???????????????????????????????????????? ???????????? ???????????? ???????????????????????????????????????????? ???????? ???????????????????????????? ???? ????????????????-???????????????????????????? ???????????????????????? ???????????????????????? – an approach advocated by the SFT Group since , and which we see more and more applied within the industry, especially in the new PIANC WG211 ‘Guideline for the design of fender systems’.
How to properly install fender systems – p. 12-19 of our ???? ????????????????????????????????????????????????, ???????????????????????????????????? ???????????? ???????????????????????????????????????????? ???????????????????????? give a step-by-step instruction.
Tensioned Chains
Foam Fenders and Vessel Belting
Pressure During Heat Lamination
Inverted Cone Fenders and Anchors
Pneumatic Fenders can be produced in different methods, the most common: wrapped and molded. Explore here the advantages of each one, and make informed choices.
Molded fenders are made from the outside in, from several molded parts that are stitched together in the final steps of the manufacturing process, while wrapped fenders are manufactured from the inside out and typically consist of a homogeneous fender body with a continuous nylon tire-cord.
- If made from several sections, the tire-cord is not continuous and stitched layers are potentially vulnerable to fail.
- Wrapped fenders, with its uniform inner rubber body, provide strength evenly.
Also, keep in mind, that regardless of the method, both are fully compliant with ISO -1:. This standard specifies the material, performance and dimensions as well as the test and inspection procedures of the finished product.
How manufacturers ???? achieve this compliance, is entirely up to them.
In terms of certification, the fender should come with a third party prototype test, aka “type approval”, guaranteeing full compliance with ISO.
Be aware, that this “type approval” is different than a one according to PIANC.
Last but not least, please also note that it is a common misconception in the maritime industry to consider launching airbags of being similar to pneumatic fenders.
Technology, structure and production methods are different; in fact, both serve totally different purposes.
There are other significant differences that make it advisable to put the decision for one or the other manufacturing method in the hands of an experienced manufacturer.
For more details, please contact your SFT closest expert.
more closeThis is valid for the moment of installation, but also for re-tensioning weight chains after some years in service. Did you know that the weight chain of a fender system is the only chain working 24/7?
It is therefore of utmost importance that weight chains are ???????????????????????????????? ???????????????????????????????????? ???????????? ???????????????????????????????? ????????????????????????????????????. As easy as the process is, as ???????????????????????????? it is for the ???????????????????????????????????????????? ???????????? ???????????????????????????? ???????????????? ???????? ???? ???????????????????????? ????????????????????????.
Get to know the details:
① The fender panel needs to be lifted slightly by a crane, to properly tighten the chain tensioners of the weight chain – it is not possible adjusting the tensioners without crane support.
② When the panel is fully supported by the crane, the chain tensioners need to be tightened as much as needed.
③ With re-tensioned weight chains, the fender panel can be lowered and released from the crane.
???? Without properly tensioned weight chains, the full fender panel weight is supported by the rubber unit only – ???? ???????????????????????????????????? ???????????????? ???????????????????????? ???????????????????? ????????????????????????????, as otherwise it can lead to cracks in the fender, especially at the top flange areas. Such failure modes, which we see in the industry more often than you think, is typically not the result of low-quality rubber compounds, but rather a flawed design of the fender system.
✔️ A holistic approach to fender system design considers the ???????????????????????????? ???????? ???????????? ???????????????????????????????????????? ???????????? ???????????? ???????????????????????????????????????????? ???????? ???????????????????????????? ???? ????????????????-???????????????????????????? ???????????????????????? ???????????????????????? – an approach advocated by the SFT Group since , and which we see more and more applied within the industry, especially in the new PIANC WG211 ‘Guideline for the design of fender systems’.
How to properly install fender systems – p. 12-19 of our ????????????????????????????????????????????????, ???????????????????????????????????? ???????????? ???????????????????????????????????????????? ???????????????????????? give a step-by-step instruction
more closeIf you see voids in a foam fender body that are large enough to stick your hand in, then there is something very strong with the fender or the manufacturing method. How can that happen?
The foam core of a foam fender is manufactured by winding foam sheets around a mandrel until the required outer diameter is reached.
As there is no industry standard, these foam sheets have different widths, ranging from ↔️ 0.15m up to 2m. Foam Fenders with lengths of several meters would need a massive amount of these small strips, compared to a couple of 2m wide sheets.
As these large sheets are more difficult to handle and considered the state-of-the-art design, smaller ones are used in the industry based on legacy processes with ????.???????????? ???????????????????????? ???????????????????????? ???????????????????? ????????????????????????????????????????????????:
① Increased risk of voids and overlapping areas between strips
➡️ Voids have no energy absorbing material, and therefore the performance of the fender is limited
② Increased risk of water ingress into the fender body
➡️ During operation, especially for ship-to-ship, the water ingress into the fender could be so massive, that the fender might reach the limit of the vessels deck equipment for pulling the fender back on board.
???????????????????? ???????????? ????????????????’???? ???????????????????????? – the foam core provides the energy absorption, and this is what you pay for.
Foam Fenders being manufactured with wide sheets substantially reduce the number of voids and overlapping areas, ???????????????????????????????????? ???????? ???? ???????????????????????????????? ????????????????????????, ensuring full energy absorption capacity.
SFT with its own manufacturing facility for foam products in Germany combines pure craftsmanship of our skilled workers with the right materials and equipment, based long-standing know-how.
For more information about Foam Fenders #MadeInGermany or if you are interest to visit our manufacturing facility, please get in touch with our sales offices around the world.
more closeBeltings are basically steel bumpers on vessel hulls. They are usually located just above the water line, but there are also vessels with belting on several different locations along the hull. Let's see why!
If vessels have beltings, it is essential that fender panels have been designed correctly with chamfers and the corresponding load cases.
(1)
Mostly seen on ferries ????, cruise ships and barges, their beltings slide up and down ⏫⏬ the panel, during tidal variations or un-/loading conditions. The chamfers are there to avoid snagging of beltings during these movements.
A chamfer has the same effect as a bevel placed on a certain side of the fender panel.
When panels do not have chamfers or these are insufficient, beltings could get stuck on or below the panel, if that happens: severe fender damages can occur.
(2)
Vessels with beltings might contact the panel at one or two points creating bending moments in the panel structure.
⬅️ A ship belting contacting the middle section of the panel imparts a line load that will cause high bending moments. This concentrated load case is severe, and the panel might fail in the contact area.
↙️ Low contact with beltings cause the panel to tilt, so that the top of the panel touches the vessel, creating a second contact on the hull. The long cantilever leads to large bending moment that the panels must be designed for.
Using a fender panel for a load case other than specified, not only implies monetary consequences for the terminal operator and costly downtimes until it is replaced, but also a safety risk.
Therefore, the consideration of beltings and the corresponding design impacts should be clearly laid out in the project specifications ????.
???? Additionally, changes in the operation at the berth should not be underestimated either.
⬇️⬇️
If a berth and its fenders were designed for vessels without beltings, a change to vessels with beltings could heavily damage the fender panels and will result in repair works and/or temporary closure of the berth.
The energy absorbing component of the fenders, the foam core, is manufactured by wounding two-meter-wide foam sheets around a mandrel. The proven and most successful bonding technology is heat lamination. Why?
➡️ to achieve a strong bonding between the foam layers
➡️ to create the solid and homogeneous fender core.
???????????????? ???????? ???????????????????????????????????? ???????? ?????????????????
⚠️ Heat lamination is superior compared to adhesives which could break down over time and therefore, could lead to bonding failure in a short period of time.
???? The heat lamination process ensures an increased life cycle and a reliable performance of foam fenders.
⏩ ⏪ The lamination has to be done correctly: Pressure is key, and without adequate pressure, the performance and life cycle of the product is impaired.
↪️ The ???????????????????????????? ???????????????????????????????? ???????????????????????? ???????????????????????????????????????????????????? ???????? ???????????????????? to basically all high performance fenders in the market, both to rubber and foam fenders.
SFT with its own manufacturing facility for foam products in Germany combines pure craftsmanship ???? of our skilled workers with the right equipment and long-standing know-how ????.
For more information on Foam Fenders #MadeInGermany or a visit to our manufacturing facility, please get in touch with our sales offices around the world ????.
more closeCone Fenders have different flange sizes on each side, a wider bottom flange and a smaller head flange. ???????????????????? ???????????? ???????????? ???????????????? ???????? ???????????????????????????????????????? ????????????????: ???? ???????????????????????????????? ????????????, ???????????? ???????????? ???????????????????????????????? ????????????.
Designers often pay only little attention to the installation of these fenders, and some projects end up with the smaller flange installed to the substructure (inverted).
???????????? ????????????????????????????:
This ‘inverted’ Cone Fender (small flange to substructure) ???????????????????????????? ???????????? ???????????????????????????????????????? ???????????? ???????????????????????????????????? ???????? ???????????? ???????????????????????? ???????????????????????? and the safety at the berth. It means that the weight of the steel panel and rubber unit introduce a large moment into the small head section of the fender over the full stand-off distance, leading to irregular compression and more stress.
???????????????????????????????????????????? ????????????:
Inverted fenders might be suitable when deflection and weight of the panel is guided, e.g. ???????????????? ???????????????????????????????? ???????????????????????? ???????? ????????????????/???????????????????? ???????????????????????? ???????????????????????????? ???????? ???????????????????? ???????????????????????????? ???????????????????? ???????????? ???????????????????????????????? ???????? ???????????? ????????????????????????, but typically not for conventional fender systems.
???????????????????? ????????????????????????????????:
???????????????? ???????????????????????????? ???????????? ???????????????? ????????????????????????, ???????????????????????????? ???????????? ????????????????????????, ???????????????? ???????????????????????????????????? ???????????????? ???????????? ???????????????????? ???????????????????????? ???????? ???????????? ????????????????????????????????????????????????. ‘Inverted’ cone fender designs should be avoided and challenged, to not compromise the operation and, above all, the safety at the terminal.
Some examples of world-class Cone Fender solutions, all individually designed and manufactured for our clients.
The size of anchors for fenders is determined during the development of the rubber unit and applied according to the fender manufacturer’s catalogue data.
In contrast, ???????????????????????????? ???????????? ???????????????????? ???????????????????????????????? ???????????????? ???? ???????????????????????????????????? ????????????????????????????????: It is important that the anchor size and length is calculated individually according to the occurring ???????????????? ????????????????s.
???? Typically, these main load cases exist:
① Full face contact by vessel with ship list
② Line load contact e.g. by belting
③ Low level impact / Bow flare contact
It is therefore of utmost importance that the fender manufacturer is aware of the anticipated load cases. ???????? ???????????? ???????????????????????? ???????????????? ???????????????? ???????????????????????????? ???????????????? ???????????? ????????????????????????????????????????????????????, ???????????????????????????? ???????????????????????????????? ???????????? ???????????????????? ???????????????????? ???????????????????? ???????????????????????? ????????????????????????????????????.
Applying loads on a fender system other than specified, could not only imply monetary consequences for the terminal operator and costly downtimes, but also a safety risk for port personnel.
???? Share the information of the anticipated load case with your fender manufacturer to make sure that anchors for chain brackets are calculated correctly, to avoid damages, unnecessary cost and safety risks ⛔️.
???? If you need any further #advice on the topic of anchors for chain brackets, please contact your local ShibataFenderTeam experts via or our contact form.
more closeBolt Tightening
Chemical Anchor
Verifiation testing
British Standard
Fender Design
Maintenance
Technical Details
Bolt tightening is an extremely important. If bolts of a fender system are not tight enough, they will become undone; if they are too tight, they may damage the fender system. Read best practice advice for you to be on the safe side:
① ???????????????????????????????? ???????????????????????? ???????????????????????? is recommended for all bolted connections ???????? ???????????????? ???????????????????????????? ???????????????? ???????????????????????????????????? due to vibrations from moored ships or wave movements. Our recommendation is to apply the thread locker (e.g. Loctite) during assembly ???????????? ???????????????????????? ???????????? ???????????????????????? from inside the sockets of rubber fenders or steel panels before. The thread locker (medium grade) shall be applied according to manufacturer’s recommendations, it cures by being exposed to oxygen. Connections can be untightened by applying reasonable force.
We furthermore recommend to ???????????????????????? ???????????? ???????????????????????? ???????????????????????? ???????? ???????????? ???????????????????????????? ???????? ???????????????????????????? ????????????????????????????????????. Any loose bolts identified during inspection or maintenance should be fixed to prevent further damages to the systems.
② Other possible locking methods include ???????????? ????????????????????????????, ???????????????????????????? ???????????????? ???????????? ????????????????-????????????????????????????. It needs to be taken into account, however, that especially tack-welding might lead to damages during loosening and some components might need to be replaced.
???? If you need any further #advice on the topic of bolt loosening, please contact your local ShibataFenderTeam experts.
more close???????????????????????????? for fender systems secure the fender system and its components to the substructure. To avoid being pulled out of the concrete is all about being threaded and a strong bonding.
First of all, we distinguish between Cast-in Anchors and Chemical Anchors:
▶️ Cast-In Anchors for a new concrete structure
▶️ Chemical Anchors for existing concrete structures
???? ???????????????????????????? ???????????????? ???????? ???????????????????????????????? ????????????????????????????: The threaded rod of the anchor is bonded with special high-strength resin-grout into a drilled hole. It is therefore essential that the chemical anchor is ???????????????????????????????? so that the grout can set in the threads and ???????????????????????????? ???? ???????????????????????? ???????????????????????????? with the concrete ???? - especially when the selected anchors deviate from standard 8.8 Chemical Anchors (e.g. as stainless steel).
➡️ ???????? ???????????????? ???????? ????????????????????????????, ???????????????????? ???????? ???? ???????????????? ???????????????? ???????????????????????? ???????????????? ???????????? ???????????????????????? ???????????? ???????? ???????????????????????? ???????????? ???????? ???????????? ???????????????????????????????? ???????????????????????? ???????????? ???????????????????????????????? ????????????????????????????.
Our international experts in the different SFT offices around the world are very happy to be in touch with you for further questions about anchors.
???? You can reach them via or our contact form.
more closeWhat is the best way for you to ensure that the final fender and the material used are compliant with your individual project requirements before the fenders are shipped to their new home?
Once the specific parameters and requirements for your project have been determined, the manufacturer starts with the manufacturing of your customized fenders.
Ensuring compliance with your requirements is done via the so-called ???????????????????????????????????????????????? ???????????????????????????? - the most relevant fender testing procedure as it confirms the performance and material quality of the product.
Verification testing consists of:
☑️ material testing
☑️ traceability
☑️ performance testing
☑️ verification of dimensions
☑️ visual checking
The first one is done on the actual rubber compound used for the production of the fender, whereas the other test procedures are performed on the final fender that has been produced for your individual project.
All of them are covered in more depth in our ???????????????????? ???????????????????? #???? ‘???????????????????????????? – ???? ????????????????-???????????????????????????????? ????????????????????????????????’. ⬅️ Download it from our website and Join The Safe Side.
more closeThe British Standard, ???????? ????????????????-????-????-????????????????, a ‘Code of practice for materials’, recommends for the materials used in the design and construction of maritime environment structures. What does it tell us? And more important, what doesn’t it?
???? It is specifically mentioned that this code of practice takes the form of ???????????????????????????????????????????????????????? ???????????? ???????????????????????????????? and is ???????????? to be quoted as if it was a specification (see Foreword V).
???? If a ???????????????????????????????? plans to specify a compound including semi-reinforcing fillers, specialist advice should be obtained from the manufacturer – it is ???????????? the obligation of the manufacturer to detail the components of their compounds (see 16.1.3/16.1.4).
???? It introduces a ????% ???????????????????? to fillers in rubber compounds – don’t let yourself be fooled here: the 5% limit is for inert and extending fillers, ???????????? for common semi-reinforcing fillers with very small particle sizes (see 16.1.3).
???? It explains that if a ???????????? testing (Thermogravimetric Analysis) is performed on a test sample and the finished fender, and results are then compared, that ???????????????????????????????????????? ???????????? ????????????????????, even between samples from the same batch, especially if different laboratories are used and if solvent extraction is not performed on both parts. It does ???????????? say that a TGA test gives an indication of quality or durability – this can only be done by physical property and durability testing (see 16.1.5).
International standards and guidelines are usually very comprehensive documents and not easy to be analyzed.
???? ???? If you have further questions about the new British Standard BS -1-4-, ???????????? ???????? ???????????????????? ???????????????? ???????????? ???????????????????????? ???????????????????????????? who are available for you worldwide ????
more closeFenders are of paramount importance in securing port infrastructures and creating a safe environment for ships and crews – they need to perform as expected throughout their entire service life, even in the most remote locations and under harshest conditions.
❗️ Fender Design builds on the foundation of engineering excellence and skilled specialists with a long proven track record in the maritime construction industry.
❗️ All steps of fender design go hand in hand and influence each other - all the components of a fender system must be designed in the correct balance and work together properly.
❗️ This concept, a ‘holistic approach to fender system design’, considers a fender system as a whole, taking into account the project conditions, its different components as well as its manufacturing process.
???? What is about beliefs, is the ???????????????????????? ???????? ???? ????????????????????????????????????????????????.
A durable fender is the physical evidence of a corporate culture that puts the performance requirements of the customer first in determining product quality, and not the company’s own need for market differentiation.
SFT believes in more ???????????????????????????????????????????????? in fender production in order to ensure quality standards that are driven by a commitment to high-performance products and a clear sense of responsibility.
more closeMaintenance is an important topic but also extensive and not always easy to grasp. So where to start? A maintenance checklist is already a helpful tool. If this is even topped up by a list of ???????????????????????????????????????????? ???????????????????????? and detailed instructions, you are ready to go.
We recommend these three maintenance levels:
???????????????????? ????: ???????????????????? ???????????????????????? ????????????????????????????????????????
Every 6 months or 1 year, depending on component
???????????????????? ????: ???????????????????????????? ????????????????????????????????????????????
For most components every 4-6 years
???????????????????? ????: ???????????????????? ???????????????????????????????????????????? ???????? ????????????????????????????????
For most components every 15-25 years
???? If you like to get assistance on how to approach the maintenance of your installations, feel free to get in touch with your local SFT office - we offer ???????????????????????????????????????? ???????????????????????? ???????????????? ????????????????????. In some cases, these are done in cooperation with our local agents.
Rely on our expertise and receive a customized maintenance schedule to prevent wear and tear and possible costly damages. Further information on maintenance levels – download our IOM (maintenance manual) for free.
▶️ Join the safe side – Work with ShibataFenderTeam ◀️
The ???????????????? ???????? ???????????? ???????????????????????????????????????????? ???????????????????????????? is to avoid or reduce the consequences of failure of equipment whilst maintaining safety at all times with a low financial impact.
With a preventive maintenance program in place, your equipment is regularly checked for wear and tear – and it is possible to replace or repair worn components before they cause a failure.
???????????????????? ???????????? ???????????? ???? ???????????????????????????? ???????????? ???????????????????????????????????????? ???????????????????????????????????????????? ???????????????????????? ???????????? ???????? ????????????????????????????:
✔️ Enable safe and efficient operations at the port
✔️ Reduce the potential for accidents
✔️ Increase the operational life of marine fenders
✔️ Reduce operational costs
Remember: The cost for downtime of the berth, liability claims and the cost to repair potential damages is always higher than carrying out a preventive maintenance program or repair equipment/order spare parts.
An ideal and well executed maintenance program would ensure ???????????????? ????????????????????????????????.
For more information on maintenance, visit our website to download our ????????????????????????????????????????????????, ???????????????????????????????????? ???????????? ???????????????????????????????????????????? ???????????????????????? and our free ???????????????????????????????????????????? ???????????????????????????????????? (available in 7 languages).
more close“Compare apples with apples” – this has always been a wise counsel and still is when speaking about high-quality durable fender systems. Quotations are based on project specifications – or at least they should be. But what if not?
Project specifications allow clients to detail their specific project needs and to ensure a common basis for expected quotations, and at the same time they give guidance for equipment suppliers/manufacturers to prepare their quotations.
❌ But what if quotations aren’t based on specifications and it is therefore not possible to compare them? Not quoting to specifications usually goes along with a lower price, making it difficult for the client to compare apples with apples ????.
When it comes to high-quality durable fender systems, the following 3 technical details should not be missed:
????. ???????????????????????????????? ????????????????????????????????????????????????????????
????. ???????????????????????????????????? ???????????????? ????????????????????
????. ???????????????????????????? ????????????????????????????????????????????????
If you are in doubt, it is better to double check with the suppliers and get detailed written confirmation for any item with ambiguity.
The SFT Group is your partner and you can rely on us – always.
more closeCyclic Load Cases
Holistic Approach
Low Compression
Fender System Design
What are ???????????????????????? ???????????? ???????????????????????????????? ???????????????????? and how do they affect the design of a fender? To find out, we need to go to the ???????????????????????????????????????? ???????????????????????????? ???? ???????????????????????????????? ???????????????????????????????? ???????????? ???? ???????????????????????????? ????????????????????????????????.
Where the berthing analysis focuses on the kinetic energy of the vessel during berthing, the mooring analysis focuses on forces on the berthed vessel, that are due to wind, current, tension lines and others. A thorough mooring analysis can prevent the fender from damages and failure. Here is how:
The mooring analysis might reveal that load cases need to be considered that include ???????????????????????? ???????????? ???????????????????????????????? ????????????????????. The main difference here is that with cyclic loads, there is an oscillation motion, whereas constant loads deflect the fender permanently until release of the vessel. Both loads could also occur simultaneously, which poses potential design challenges to the fender and its life cycle.
Examples for cyclic and constant load cases are permanent mooring situations, like
➡️ FSRU’s
➡️ floating docks
➡️ stationary vessels, like museum vessels (e.g. the barque ‘Peking’ in Hamburg)
Taking into account cyclic and constant loads during the design process, the designer needs to focus on the ????????????????????????’???? ???????????????????????????????? ????????????????????, to make sure that wind and other loads do not exceed the load limits of a fender. But most important, the ???????????????????????????????????????? ???????? ???????????? ???????????????????????? under cyclic and constant loads should be limited.
That could be achieved by
☑️ a correct mooring arrangement, and/or
☑️ an oversized fender where the expected loads correspond to a 5-10% deflection of the fender.
???? ???????????????????????????? ???????? ???????????? ????????????????????, ????????????????????????, ????????????????????????????????????, ???????????????????????? ???????????? ???????????????? ???????????? ???????????????????????????????????????????????????? ???????????????? ???????????????? ???????? ???????????? ???????????????????????????????? ???????????? ???????????????????????? ???????? ???????????????????????????????? ???????????????????? ???????????? ???????????????????? ???????????????????????????? ???????? ????????????????.
If not designed for cyclic or constante loads but being exposed to such, any fender will fail. Unlike berthing loads, cyclic loads have a certain constant period of oscillation.
These loads can cause cyclic or permanent deflections. The consequences are severe!
If a fender is not designed for cyclic or constant loads but then being exposed to it, e.g. 10 deflections per minute, there are two components that could lead to failures:
①one is the heat build-up in the fender (fatigue)
② and the other is the overstress of the rubber, leading to early deterioration of materials and a premature failure
What makes a difference is a thorough mooring and berthing analysis and a customized design of the fender system, taking into account all project requirements – a holistic approach to fenders system design. This is also addressed and picked up by industry guidelines and standards to improve the safety and efficiency in the industry.
Summing up:
☑️ Choose a fender manufacturer who focuses on a holistic approach
☑️ Make sure all conditions of the cyclic and constant loads are analyzed and well known before the fender design phase starts
☑️ Receive a customized fender system for your requirements to protect your quay wall, avoid accidents and downtime
Join the safe side – Work with ShibataFenderTeam
more closeMany different aspects need to be taken into account. If the focus is only on a few of those aspects, the quality, durability and the guaranteed safety that is expected from a fender are lacking.
This is why a ???????????????????????????????? ???????????????????????????????? is needed, taking these three aspects into account and treating a fender system as one:
Only when all of these aspects are valued equally, are interconnected and seen as one single process, will the fender system perform as expected.
PART I: What is so important about project conditions?
???????????????????????????? ????????????????????????????????????????, such as berthing energy or local weather, are very individual and have a tremendous impact on the fender design. If something goes wrong with the berthing energy calculation of vessels, the entire waterfront design could be at risk.
Those aspects, and the different characteristics of various fender types are to be incorporated in the fender design process. Our in-house engineering team relies on years of experience in the maritime industry and considers all the many conditions to design a unique fender system.
All SFT fenders are designed and manufactured following a holistic approach. Join the safe side – Work with ShibataFenderTeam.
A holistic approach to fender system design ensures that a fender system performs as expected and that the safety in marine operations is not at stake.
PART II deals with the question ‘What is so important about the different components of a fender system and their interaction?’
A fender system is made of ???????????????????????????????????? ????????????????????????????????????????: rubber unit, steel panel, chains, anchors, fixings and PE plates. A holistic approach makes sure they are all designed in the correct balance ???? and work together properly. Since the rubber units are mostly standardized in the industry, the main engineering and design challenge is with the steel panels, chains and the corresponding anchorage.
Typical problems in poor fender system design are:
▶️ the rubber fender position on the panel,
▶️ chain layout,
▶️ the steel panel’s internal structure,
▶️ UHMW-PE protection pads, and
▶️ coating system.
The picture above gives a good example of three typical problems of poor fender system design: Unfavorable panel position (P1), chains with incorrect angle (P2) and low rubber quality with incorrect design (P3).
Poor fender system design has many faces with severe consequences for ports, ships and people. These are often a dramatic reduction in the operational life of the system. Several measures help to prevent failures and minimize risks and they all follow ???? ???????????????????????????????? ???????????????????????????????? ???????? ???????????????????????? ???????????????????????? ????????????????????????. It is of vital importance for your project to have a partner at your side who has a proven track record and experience with the design and manufacturing of high-quality fender systems.
All SFT fenders are designed and manufactured following a holistic approach. Join the safe side – Work with ShibataFenderTeam.
Our video shows how a fender system comes to life ????.
Compression set is an important metric for foam fenders and can have significant impacts on their performance. But first of all, what is compression set?
???????????????????????????????????????????? ???????????? is the amount of permanent deformation of a material after it had been compressed. Or seeing it from another perspective, it is the percentage that a material fails to recover of its original height after being compressed. ????
Or seeing it from another perspective, it is the percentage that a material fails to recover of its original height after being compressed. For example, a compression set for foam fenders of 20% indicates that the foam fender only regained 80% of its uncompressed diameter.
There are several reasons for that:
▶️ overloading
▶️ insufficient foam density for the application
▶️ manufacturing method
Fenders which are laminated with small strips of foam are more prone to that, due to the higher probability of gaps in-between the layers and potential bonding failures between layers. This can be avoided by using wide sheets of 1.5m – 2m, which is the SFT standard.
Co????sequences are simple but severe. If a foam fender’s compression set is too high, it’s diameter is smaller than before. This can lead to
▶️ Clearance issues especially for ship-to-ship operations
▶️ Reduced energy absorption of the fender
▶️ Smaller deflection as the fender only recovers to a smaller amount of its original diameter
▶️ Reduced life time, higher cost of ownership to the early replacements
▶️ Fender is less sustainable as the foam core is permanently damaged and the fender needs to be replaced
Manufacturing and designing foam fenders requires longstanding expertise and skills – something where you can truly rely on us. We manufacture foam fenders of various sizes at our own production facility in Germany, from Ocean Guard Fenders, to Donut Fenders, to Buoys.
have a look on our website and learn more about Foam Fenders
more closeA complex route lies ahead to get a high-quality and durable fender system to protect vessels, port infrastructure️ and people.
For more information, please visit Shield Type Steel River Dam.
Three aspects need to be taken into account when following ???? ???????????????????????????????? ???????????????????????????????? ???????? ???????????????????????? ???????????????????????? ????????????????????????.
PART III explains why the manufacturing process makes a difference.
The ???????????????????????????????????????????????????? ???????????????????????????? of the rubber unit plays a vital part in the ultimate performance of a fender system, same as for steel parts and PE. A holistic approach ensures that all manufacturing steps are interconnected, from compounding to mixing, molding/manufacturing, curing and de-molding.
There is a common misconception in the industry that good raw material alone will ensure a high-quality fender – this is not the full story ????. Of course, good raw material is very important and the foundation, but there is a lot more. If a rubber unit is produced from the best raw material and with a balanced compounding, a wrong mixing process or low-quality equipment can still harm the final quality of the rubber unit.
The lack of this holistic approach concept in industry standards ???? and the many examples of poor fender system design around the world emphasize the need for more attention to this topic. Already in a first step, the awareness of all the aspects and their interconnection will increase the understanding in the industry about potential problems with fender system design.
SFT owns and operates first class ???????????????????????????????????????????????????? ???????????????????????????????????????? for rubber fenders, steel panels, foam fenders and PE plates. All SFT fenders are designed and manufactured following a holistic approach. Join the safe side – Work with ShibataFenderTeam.
more closeOil, gas and LNG terminals have one thing in common: the highest safety levels in the industry, since just the smallest incident could results in major and sometimes fatal accidents. Therefore, ensuring the highest safety level is the most important consideration when designing high performance fender systems for these terminals. So what is important?
PART I
????
Hull Pressure
A Low hull pressure is required for oil and gas carrier, but especially for LNG carriers, which is why these terminals need fender systems which reliably ensure low hull pressure during berthing. This can be achieved by using fenders with a linear increase of energy absorption and reaction force – such as Foam Fenders or Pneumatic fenders.
A back-to-back fender solution in a Parallel Motion Fender configuration could be another suitable option. Here, two rubber cone fenders are mounted “back-to-back” between the substructure and the steel panel using different rubber hardness grades – this can ensure a soft landing especially if smaller vessels berth at the terminal as the reaction force will not be that high during the initial deflection of the softer fender.
Reaction force to substructure
Usually, oil, gas and LNG terminals are constructed using dolphins as their substructure. Dolphins are very different compared to bulkhead concrete substructures which is why the reaction force plays a vital role. As dolphins are pile structures, they are more load sensitive than concrete bulkheads, therefore the reaction forces introduced into the structure is typically limited. Using an appropriate fender type being designed exactly for such a berthing situation is mandatory to prevent damages or accidents.
Fender Type
The following fender types are very suitable for oil, gas and LNG terminals:
▶️ Foam Fenders with their linear increase in energy and reaction and their characteristic of adapting to the shape of different types of vessels
▶️ Parallel Motion Fenders with their characteristic of low hull pressure and their ability to provide the same energy absorption at any impact level, together with the advantage of reduced reaction forces for the substructure. Additionally, Parallel Motion Fenders avoid a second contact on the hull of the vessel, limiting the risk of damages to the vessel.
Reliability, durability and safety are always of utmost importance for the design of fender systems, but a spark more important when it comes to fender systems for oil, gas and LNG terminals. Join the safe side and partner with SFT for your next project.
SFT reference projects for oil, gas and LNG terminals.
In Part II you will learn why cyclic loads are a special topic for FSRUs and what the protection of steel parts is all about.
more closeEnsuring the highest safety level is the most important consideration when designing high performance fender systems for oil, gas and LNG terminals. Already the smallest inicident like a spark could results in major and sometimes fatal accidents. So what is important?
???????????????????????????? ???????????????????? ????????????????????
▶️ Flying sparks are a sensitive issue in such an environment, making it mandatory to protect all steel parts. The steel panels of the fender systems are protected with UHMW-PE pads, while there are several solutions for the accessories: protective sleeves, chains embedded in rubber or covered in Polyurethane, and a special coating.
???????????????????????? ????????????????????
Besides shore based LNG plants, FSRUs (Floating Storage and Regasification Units) are a common alternative to import and transfer LNG.
▶️ Typically, FSRUs are permanently moored at a dedicated berth. The fenders for such a berth are normally not designed for a berthing loads, as this usually only occurs only once when the FSRU arrives at the berth and the conditions during berthing are very controlled and maneuvering is performed with extreme caution. The design focus is on the permanent mooring situation. The FSRUs do not remain in a steady and stable position, as winds and currents have an influence on the vessel, causing a slight but enduring movement. This movement results in frequent small deflections of the fenders – so-called cyclic loads. During the design process, the designer need to focus on the fender’s reaction force, to make sure that wind and other loads do not overcompress the fender. But most important, the deflection of the fender under cyclic loads should be limited to about 5-10%, which could be achieved by the correct mooring arrangement, and/or an oversized fender where the expected loads correspond to a 5-10% deflection of the fender.
Reliability, durability and safety are always of utmost importance for the design of fender systems, but a spark more important when it comes to fender systems for oil, gas and LNG terminals. Join the safe side and partner with SFT for your next project.
SFT reference projects for oil, gas and LNG terminals
more closeFender System without Chains
Corrosion Protection and Coating Systems
Open Panels vs Closed Box Panel
Hydraulic lock-up
Calculating Hull Pressure
Fender Deflection
A fender system needs several types of chains to perform as expected – weight chains, tension chains, and sometimes also shear chains.
Each chain type has its own responsibility:
The very same fender system at exactly the opposite stage of its life cycle. A fender system needs several types of chains to perform as expected – weight chains, tension chains, and sometimes also shear chains. Each chain type has its own responsibility:
The ???????????????????????? ???????????????????? of a fender system supports the weight of the panel and avoids sagging and is providing support in cases of vertical shear. It is the only chain that works 24/7, the other chains are only active when the fender is being compressed.
An incorrect ???????????????????????????? ???????????????????? design could diminish the energy absorption of the fender system at low level contact.
???????????????????? ???????????????????????? are recommended for applications where large horizontal shear forces are expected, e.g. at ferry terminals or when vessels are winched along the quay.
Incorrect or even missing chains can have several negative impacts.
???? ① It shows an Element Fender System that was installed without chains, following the requirements of the designer, against our strict recommendations. It is clearly visible that the rubber fender is sagging, as tension and weight chains are missing – the panel’s dead weight is only supported by the rubber unit. This leads to more stress in the rubber unit, resulting in cracks, and ultimately lowering its performance and service life. Some might say, that would not happen with a “good” rubber fender, but the laws of physics are what they are, so don’t fall for that.
???? ② Later, chains were installed as the user pushed for that – the result is obvious: a fender system with a supportive chain, all in all a high-quality and durable system. Some of the rubber units needed to be replaced though, following their damage by the incorrect design.
Correctly designed chains will protect the rubber unit against excessive weight introduction and premature failure.
This high-quality design ensures a long service life, high performance and no additional maintenance cost. Our #engineering team has a long proven track record in the design of marine fender systems - Join the safe side and partner with SFT for your next project.
You will find more information about chains on our website.
more closeThe life cycle of a fender system, especially the steel panel is only as good as its corrosion protection, mainly the panel coating system.
There are several different coating systems all covered by ISO which is the adopted coating standard for the marine and off-shore environment:
> The typical coating system which consists of 2-3 epoxy layers has a service life of up to 15 years in the marine environment
> There are additional layers of corrosion protection that can be added, especially if the fender system is used in a highly corrosive area. > There are duplex systems that combine epoxy coating systems with metalizing, which is the process of spraying molten zinc or aluminum on the sandblasted panel before the application of the epoxy coating
If you require a duplex coating system for your project, be aware that some companies on the market try to convince you that a #zinc rich primer is the same as metalizing, just because it contains the word zinc. Zinc rich primers are just part of a standard #epoxy coating system and have nothing in common with metalizing. It’s just a simple wet primer that is applied on the panel before the other layers of epoxy paint are added. Metalizing on the other hand is a much more complex and expensive process where zinc or aluminum is molten in a spray gun and then applied to the steel panel where it then cools off and cures. If two companies offer you a duplex system, and there is a price difference of 20-30% between the systems, you can be sure that one of them is not quoting you the correct materials.
If you have any questions on coating and corrosion protection, our fender experts are pleased to assist you!
The most important difference between CV (constant slow velocity) and RPD (rated performance data) values, is that CV values are based on laboratory test values while RPD values reflect operational conditions.
???? When designers use CV values only for the selection of the fender units and for designing the size of the steel panel accordingly, forces will be underestimated.
Why is that? CV values are based on constant slow velocities of 0.-0. m/s. Due to the viscoelastic characteristics of rubber, fenders behave differently when compressed with different speeds: slow speed leads to lower forces, high speed leads to higher forces. As the panels are designed for berthing speeds in operational conditions, operational speed needs to be used for the calculation to receive a realistic result. If done incorrectly with CV values only, panels will be too small and hull pressure will be too high, which could lead to vessel damages and heavy liability claims. ❌
If you want to learn more about the correct values to apply, contact us and don’t risk major liability claims by the final users.
more closeUsing closed box or open steel panels depends often on the region of the world and local preferences as well as the thought that open panels are cheaper than closed box panels.
Looking that the full story and based on current PIANC recommendations, closed box panels are not necessarily more expensive, especially if you consider the full life cycle cost. As per PIANC, if steel plate are exposed on two surfaces, the min. steel thickness is 12 mm. That would be applicable to open panel, as all plates are exposed on two surfaces. Even if the plate could structurally be thinner, a 12 mm plate for the entire system is a must.
♋️ Looking at closed box panel, here the plates are only exposed on one surface, with the advantage that these plate only need a min. thickness of 9-10 mm and inside members could even be 8 mm, as they would never be exposed. You could argue that an open panel does not need a back-plate and therefore the savings compensate for the thicker steel plates. Often, that is not the case, as the back-plate provides a lot of strength to the fender panel, i.e. you can use less or thinner (min. 8 mm) inside leading to an overall lighter panel design. Even if the closed box is heavier, which can be the case in certain design, clients’ needs to consider the maintenance aspect as well, over the typical life cycle of 15-20 years.
Open panels have a much larger surface for potential corrosion, trapped water, debris getting stuck on or behind the panel – all leading to higher maintenance and service cost. Also the rehab of such a panel is more difficult due to the larger and uneven surface area. Closed panels on the other hand, have only 4 exposed surfaces, which are even, easy to access and easy to clean, sandblast and coat during life extending full scale maintenance works.
If you are unsure which way to go, check with the SFT Group to get a comparison and recommendation of the way forward for your particular project.
more closeWhen cone or cell fenders are submerged, it is recommended to provide a water drainage system that effectively drains water from the inner cavity of the fender.
There are several systems on the market, where some companies simply add small recesses in the rubber unit to drain the water. Considering the amount of water in a fender cavity, the only way to sufficiently drain the water is with a custom designed drainage system through the substructure or steel fender panel.
???? Another issue to consider is marine growth that could clog-up the drainage system, especially if there are only small rubber recesses. It is therefore recommended that the drainage system is considered in the initial design of the fender system and substructure. Especially for fender systems on mono-steel piles, there are some very simple and economical drainage solutions that can be integrated into the connecting flange between pile and fender. For further questions or design suggestions, please contact your local SFT office.
more closeNot only the design of weight, tension and shear chains are most important, also the attachment of these chains to the panel needs detailed attention.
The chain lugs have to be designed to withstand major forces when chains are engaged during berthing. Therefore, not only the lug must be designed with sufficient capacity, but also the interface to the panel.
❗️If chain lugs are just welded to the backplate of the panel, the interface is not providing the needed strength and the lug could pull of the back plate from the panel, like a can opener❗️
✔️ Only if the lug design incorporates the interface and welding to the internal structural members of the panel, the lug has sufficient strength to accept the high forces during berthing ✔️
Pay attention to this detail when reviewing designs and drawings to avoid steel panel failure and downtime at the terminal. Only engage with fender manufacturers that live a holistic approach to fender design, only then you can be sure that the fenders will perform as intended. Contact your SFT experts for more detailed information.
more closeTheoretically, hull pressure (HP) is distributed evenly if the fender reaction into the panel is symmetrical. For some designs however, that is not always possible.
And an off-center peak reaction needs to be tolerated, while the average HP remains the same.For such design cases, the rubber unit is positioned below the upper third of the panel, so that the peak HP is no more than double the average HP.
Rubber fender positions above the upper third of the panel should be avoided, as peak/average hull pressures could be very high, as the lower part of the steel panel is ineffective for hull pressure. But, how is HP calculated at low contact then? Assuming a single fender unit system, there is actually no hull pressure, there is only a line load as the panel rotates at contact, introducing a line load into the panel and the vessel.
Typically, vessels can only resist a limited pressure on their hull, therefore it is crucial to determine the fender contact pressure, based on the vessels draft and freeboard in connection with tides and mounting elevations, to ensure allowable limits are not exceeded.
When it comes to HP, be aware that there are several load cases and scenarios to consider for your project. If you are not sure about the right approach, contact your nearest SFT office for support.
Each type of fender has a specific design deflection, which is the point to which the fender can be safely deflected.
Therefore it is a must for any performance test to be executed up the to the design deflection.
The percentage of design deflection may vary from manufacturer to manufacturer.
To determine if a fender passes or fails a performance test as per PIANC and ASTM F, the deflection at which the min. E/A and max. R/F occurs, does not matter, as long as the required values are achieved prior to the design deflection. That means, the fender must be deflected to its design deflection, but the minimum E/A and max. R/F may be achieved earlier along the performance curve. In that case, the fender has actually some reserved capacity which might be a welcome ⛔️ buffer in case of an accidental berthing, like berthing speeds over the operational limits.
more closeCombined Shear Compression Testing
Bollard Selection
Physical Properties Testing
Efficient Fenders
Floating Fenders
Velocity Factor and Energy Absorption
In our post from a couple of months ago, we explained shear compression testing as an alternative to standard durability testing.
In order to fully utilize this test approach for your project, we have introduced a new test protocol for high performance fenders like Cone or Cell Fenders, a combined shear compression test.
Only a combined and simultaneous shear compression testing provides the information you need to make sure your fender is up for the job. More and more clients realize that and start implementing this into their test requirements.
Model testing with 25k cycles and full scale testing with typical 1-3 cycles is possible. Due to the cost and time involved, full scale testing with max. 3 cycles is recommended for your demanding and sensitive projects.
⚠️ Keep in mind that fenders typically experience compression and shear at the same time when being used at the berth. ⚠️
more closeWhen comparing the two materials, it can be noted that the use of the respective material has advantages and disadvantages.
Therefore cast-iron as well as ???? cast steel bollards have their place in the industry, for example.
???? Ductile Iron Bollard:
Ductile iron bollards have a high impact strength and high corrosion resistance, that ensures a long service life. Due to its typical material properties, this type of bollard material is recommended in moderate climate conditions. This material is commonly used throughout the industry and provides a good combination of performance, strength and longevity. Ductile Cast Iron bollards can be installed with cast-in or resin anchors. It is important to determine the anchors of the bollard based on the design of the concrete reinforcement.
???? Cast Steel Bollard:
Cast Steel bollards have a high impact strength and can especially be used in cold climate areas down to -20°. Moreover, the bollard material can be welded to a steel substructure without compromising the material strength. Additionally to the safety of people, the correct dimensioning ✅ of bollards secures the integrity of the quay wall / . (welded connection to the plate) on cast steel bollards can be integrated, which acts as a predetermined breaking point above the quay substructure to avoid any damage in the event of an overload (detailed design needs to be checked with the project requirements). However, it should be noted that cast steel bollards are more prone to corrosion (if painting is damaged) and therefore require more frequent maintenance compared to ductile iron bollards.
If you are interested in bollards and need further information, please reach out to our experts
more closeThe below table compares the most commonly used material properties of cast steel and ductile iron for bollards.
Comparing both materials which are commonly used for bollard manufacturing, Cast Steel as well as Ductile Iron have a similar Yield Strength (point that indicates the limit of elastic behavior and the beginning of plastic deformation – pulling of a mooring rope). Comparing the Tensile Strength of Cast Steel and Ductile Iron, it can be stated that Cast Steel has a higher value ???? (point of fracture of the material).
However, the use of stronger material does not imply a stronger bollard, as the overall working capacity is relevant for the overall design of the bollard. ???? For this reason, Cast Steel bollards require a thinner wall thickness and have a good cost to weight ratio.
At the next Technical Tuesday, we will explain which cast material is most suitable for which application. Stay tuned!
If you are interested in bollards and need further information, please reach out to our experts.
Material
Grade
Yield Strength (MPa)
Tensile Strength (MPa)
Elongation (%)
Cast Steel - EN
GE 300
>300
min. 520 – max. 750
>15
Ductile (SG) Cast Iron - EN
EN GJS-450
>310
>450
>10
more closeVarious types of vessels are safely moored on bollards for a period of time during loading and off-loading conditions.
The safety and reliability of the mooring equipment chosen, is extremely important. Thus, some aspects need to be considered for your bollard selection.
Bollards can typically be manufactured from 3 different types of cast material:
- Ductile Cast Iron (Spheroidal Graphite Cast Iron)
- Cast Steel
- Grey cast iron
Grey Cast Iron has excellent castability and provides long-term resistance to corrosion and wear.
However, nowadays, Ductile Iron and Cast Steel are usually preferred due to its superior strength to weight ratio.???? Therefore the below table focuses on Ductile Iron and Cast Steel, to provide a first comparison of the most important characteristics:
The selection of the ‘right’ bollard material depends on different factors and conditions (e.g. sub-structure, climatic conditions, application etc.) in the port.
At the next Technical Tuesday, we will compare the material properties of Cast Steel und Ductile Iron and explain which cast material is most suitable for which application. Stay tuned!
If you are interested in bollards and need further information, please reach out to our experts:
more closePhysical properties testing cannot be performed on the final product, which is why these properties have to be tested on conform sample rubber sheets.
Testing can also be done by the customer themselves when a rubber sheet made from the same compound as used for their fenders is tested.
Each property and standard has their own conditioning parameters like storage conditions or timing of the test, and the testing processes have to strictly follow that. If tests are not done according to the mandated parameters, results could vary from the requirements. Always double check condition time and storing requirements with the respective standard or consult your fender manufacturer.
Customers can also test the composition of the rubber sheet to check for traceability by performing a TGA test. This is done to verify that the compound of the sample sheet used for physical property testing is the same compound that was used in the final product. Traceability verification is done by comparing TGA results of the final product with the results of the rubber sheet. The results should be similar but can deviate to some degree due to laboratory conditions.
For further details, please contact us.
Fender selection is about much more than efficiency, which is why only experienced and design-oriented manufacturers should select the most appropriate fender.
The following factors should be considered when selecting a rubber unit for a fender system:
???? Minimum/maximum stand-off, deflected and undeflected.
???? Installation area on the substructure
???? Positioning of the rubber unit, based on the steel panel elevations and the rubber unit centerline
???? Type of substructure
???? Experience and preference of the user
???? Type of terminal
It is important to not only consider the rubber unit as a single component, but to apply a holistic approach to the entire fender system design. Therefore, generic online tools for fender selection could lead the designer on the wrong track.
For example, fenders for some naval vessels with large bow flares require systems with a larger stand-off, while container terminals aim for the smallest possible clearance to ensure that cranes can reach the last container row of the ship.
Have you ever wondered why floating fender systems are often designed with oversized chains? First of all, you need to keep in mind that floating fenders are in motion 24/7.
This causes constant wear on the shackles and chain links due to friction.
Therefore, oversized chains are used to account for this constant wear and provide a kind of wear allowance for the chains and shackles. The weight of the large chain could also limit the movement of the fender.
Anchors for floating fender systems are usually designed for the characteristic load only, since designs based on MBL would result in an over-engineered anchorage and excessive edge distances.
Tack welds or half/full welds on the shackle pins are recommended for certain applications to prevent that shackle pins become loose, fall out and fenders drift away.
If you are interested in floating fenders and need more information, please contact our fender experts.
When testing fenders, the applied load is measured and a corresponding load-deflection curve is determined. The curve informs on the reaction force and energy absorption.
❗️ The fundamental difference between determining the reaction force and energy absorption is that the maximum reaction force is a point along the curve, while the energy absorption considers an area ❗️
For buckling ???? type fenders, the highest reaction force usually occurs at the so-called first peak of the curve, i.e., at about 30% deflection. It is important to keep in mind that the decreasing velocity during berthing, leads to different R/F velocity factors at every % of deflection, i.e. that the max. reaction force represents one point along the curve. The energy absorption of the fender is not measured, but calculated by integral calculus based on the area under the load-deflection curve.
❗️ Furthermore, the difference in the reaction force curves for high and slow speed compression does not lead to a simple parallel shift of the curve, it rather results in a differently shaped curve ❗️
Comparing the reaction force curves of ‘CV R/F’ and ‘RF at 150mm’ in the figure, it is clear that the shapes differ, which is due to the higher initial compression speed of 150 mm/s compared to 1.33 mm/s. The viscoelastic property of the rubber leads to the phenomenon that a fender is stiffer when compressed at higher speeds, therefore the reaction force curve is steeper, especially in the beginning and overall at a higher level than the curve at slower speed. This steeper and higher ⤴️ curve results in a larger area under the curve and thus a higher energy absorption.
The differently shaped curve leads to a velocity factor for the reaction force, that must necessarily be different than the velocity factor for the energy absorption. The Japanese Society of Civil Engineering investigated that topic in their ‘Journal of structural engineering VOL. 55A’ and also reported such findings.
If you would like to learn more about this topic, please contact your SFT office.
Materials Testing
RPD vs CV
Type Approval Testing
Fender Selection
Fundamental Testing
Physical Properties Testing
Edge Distance
As part of verification testing, the material testing is of utmost importance for the client as it confirms the physical properties that ensure the durability and if the material is “fit for use” as a fender.
Rubber compounds can have very different compositions, depending on their required performance criteria which have to comply with international standards and guidelines like PIANC, ASTM D, EAU , ROM 2.0-11 (), or BS.
???? These guidelines ensure that a fender performs as designed when installed at a berth.
• The rubber samples that are needed for the physical property testing are taken from the finalized compound. They are precisely prepared and then cured at a laboratory.
• Afterwards, they are tested under strict laboratory conditions, including tensile and bonding strength, compression set, hardness, elongation, tear and abrasion resistance, chemical and ozone resistance, and aging.
The most significant difference between CV (constant slow velocity) and RPD (rated performance data) values is the compression/berthing speed and resulting reaction forces.
Some designers use CV values only in their fender and substructure designs without the needed correction factors, and might underestimate these loads. The difference in reaction force or load into the substructure, between CV and RPD values is in the range of 20-40% and could therefore have a substantial impact.
Why is that?
???? CV compression speed is 0.33-1.33mm/s (2-8cm/min) which is the typical speed used for fender testing.
???? RPD is based on 150mm/s which is close to or the typical berthing speeds in today’s project specifications.
Due to the viscoelastic characteristics of rubber, fenders behave differently when compressed with different speeds: slow speeds lead to lower energy absorption and reaction forces, whereas high speeds lead to higher energy absorption and reaction force values. If RPD is used, both values are in the correct range, as different velocities around the 150mm/s typically have only about 5%ish impact on the loads.
Fender testing is a complex and capital-intensive topic, not only in theory but also in practice. Even more important is a reliable and 'fit for us' testing equipment, as test frames are an elementary part of the performance testing process.
It is necessary that calibration is performed per test equipment components, but it is most important that items are calibrated as a group as well.
The load cell set-up, verification testing and other settings should be discussed and agreed before testing any fender. After the set-up and details are clarified, fenders are compressed up to their design deflection, while the reaction force is measured with load cells and/or pressure transducers. It is especially important for large fenders that the test frame has a sufficiently long stroke, in order to reach the required deflection of the fender.
⚠️There are test companies and institutes in the market that offer fender testing with makeshift test frames, that are by no means comparable to purpose built test frames of the manufacturer.
Get more insights into fender testing from our White Paper.
more closeIn order to obtain a product type approval or type examination certificate for a fender, the respective tests need to be witnessed or performed and verified by an independent and certified third party.
The purpose of fenders is to ???????????????????????? the kinetic energy and to ???????????????????????????????? the reaction force via different components of the fender onto the vessel hull and into the berth substructure.
High energy absorption while having acceptable reaction forces is key to a good fender system design. However, simply calculating ???? the berthing energy requirements results in a long list of suitable fender types and sizes
How to select the right fender?
There are many other factors which need to be considered ✔️, like: vessel details (e.g. vessel type, hull pressure, beltings), berthing information (e.g. berthing mode, type of substructure, fender spacing, stand-off requirements), project conditions ????, preferences of the client ????, and more. Selecting the right fender for your specific project needs a unique approach and cannot be done by an automated tool.
The topic of fender selection again shows why it is beneficial to rely on ???????????????????????????????? ???????????????????????????????????? ???????????? ????????????????????????????????????????.
Contact us ???? ???? for a ???????????????? ???????????????????????????????????????????????? – we are available already at the design stage of your project.
more closeFundamental testing is carried out using a scale model to establish catalogue performance data and to determine correction factors which are the fundamental data for a product type approval.
???? WHEN? Since these tests are designed to establish fundamental data during the development of a fender type or for a one-time specification, fundamental testing is not suitable to be performed for every fender project due to the high time and cost expenditure.
Published fundamental testing data includes standard performance, correction factors (e.g. temperature, velocity, angle) and test results, whereas any technological research and development results are used exclusively by the manufacturer for product improvement and remain confidential.
Read more about the different testing methods for rubber fenders in our new SFT White Paper ‘Testing. A Best-Practice Approach.
It is sometimes asked within the industry why physical properties testing can typically not be performed on the final fender itself instead of preparing test samples from the compound before production.
???? Testing physical properties from final fenders is unusual and very difficult, since it would involve cutting larger pieces out of a final fender which could damage the fender. The reason for this is that a lot more material is needed for the physical properties testing than for the traceability testing. Also, deviations of 15-20% to the catalogue values need to be taken into account, because the preparation and vulcanization under laboratory conditions of the 2 mm test plates ???? differs from the preparation of test plates, cut from a finished fender.
The Japanese OCDI Guidelines on fender design and testing puts it this way when it comes to comparing results of test plate made in the lab vs. cut from the finished fender – “...it is impossible to match the physical properties to those on any section of the product”.
For more information, please refer to our new White Paper #4 on Testing which is available for free.
The edge distance of the chain brackets and fender anchors, is a vital part of a fender system design. Especially existing structures pose challenges as modifications of the structure are often difficult.
Sometimes, the edge distance is forgotten when designing ???? substructures for new constructions and issues could be avoided by consulting with fender manufacturers about general fender system layout including chain positioning. Therefore, we recommend to consider the following during the design stage of fender projects:
???? The edge distance is most critical for chain anchors, as these are under tension when the fender system is in use
???? Recommended edge distance for initial layout design is about 10x the anchors diameter in any direction, including the depth
???? Small edge distances are possible, but then the designer (not the fender manufacturer) needs to check the quay wall design and might incorporate additional rebar based on the forces provided by the fender manufacturer
Besides the edge distance, the thickness of the quay wall section at the fender location as well as the grade of the concrete should not be underestimated in the anchor design.
Tension Chains
Fender Shear Chains
Weight Chain
Chemical Composition
Thermogravimetric Analysis (TGA)
Rubber Blend
Tension chains (or restraint) chains are an essential component of a panel fender system, and works in several ways.
????1) Balance the forces in the fender system, maintains position and alignment of the panel
????2) Prevent mooring lines being caught behind the panel (when installed at the top of the panel)
????3) For a cantilever fender system, preventing outward movement of the top/bottom of the panel, during low/high level contact. Lower tension chains are only applicable for special applications.
The location and angle of the chain will affect the fender systems performance. It is recommended that the chain is installed perpendicular to the wharf face, and when used in cantilever fender systems, should be at a practical distance above or below the centre-line of the rubber unit. This ensures sufficient compressed of the fender, providing the needed energy absorption for e.g. low impacts and avoids collision of the panel with the substructure.
If you want to learn more about optimising the use of tension chains in your design, please contact your local fender expert.
Shear chains are recommended for applications where large shear forces are expected, e.g. at ferry terminals or when vessels are winched along the quay.
➡ Installed at an angle of 40° - 45° when fender is undeflected, resulting in about 30° under deflection
➡ Makes an arch movement during compression; therefore, small angle is required, otherwise chains would extent too much and not engage when needed
➡ Need to be installed in the fender center or above and below the fender for proper functioning
➡ Typically, biggest chain of the system, each side takes the full load
➡ Quay wall area and fender location need to allow enough space for shear chain installation and sufficient edge distance for brackets - particularly important for first and last fender position on a quay wall
Shear chains might not be needed for standard applications, leading to reduced maintenance cost.
For further information about chains and their layout in a fender system, please consult our Design Manual ???? (free download in six languages ) – or for a personalized answer, call your local SFT office ????!
more closeA panel fender system consists of the rubber unit, the steel panel, and the chain system, i.e. – tension and weight chains, and sometimes shear chains.
???? Did you know that the weight chain of a fender system is the only chain working 24/7? It supports the weight of the panel and avoids sagging – the other chains are only active when the fender is being compressed. ♒️
???? What you should know:
↪ The ideal angle between the substructure and the chain should be 30-35° to provide full support for the fender panel
↪️ If the angle is larger, like 50°, the chain cannot support the panel: all the weight and force of the panel is introduced into the rubber unit (P2)
↪️ The rubber unit might develop cracks, especially at the top flange areas (P3)
We often see fenders with these kinds of defects and make people aware that in a lot of cases, the failure is not the result of low-quality components, but rather a flawed design of the fender system.
A holistic approach to fender system design considers the balance of all components and its interaction to achieve a high-quality fender system.
more closeA lot has been discussed about compounding and chemical composition for rubber fenders within the maritime industry.
PIANC Working Group 211, dealing with the new “Guidelines for the design of fender systems”, has achieved a breakthrough recently and can finally provide clarity for the industry:
Independent rubber experts stated:
SFT’s member in the Working Group, Dominique Polte, is relieved that the ongoing discussion is solved once and for all: “The SFT Group is working towards more transparency in fender production and a clear sense of responsibility from fender manufacturers. We are advocating since many years that it’s the physical properties of a fender, that proof a high-quality product and not the chemical composition, as it has stated by independent rubber experts numerous times.“
more closeTGA is a method of thermal analysis in which a sample of a rubber fender is continuously weighed during controlled heating.
By performing a TGA, you are able to:
What a TGA does not do, is verifying the quality of a product. There are no international standards giving guidance which chemical composition is favorable. This is plausible when considering the different reinforcement requirements of different rubber blends and the resulting varying amounts of other components.
Chemical composition is important in fender production, but not everything. It is the physical properties that ultimately determine the quality of a fender. ✅
Curious to learn more? Our White Paper on Compounding is available as a free download.
more closeTypically, rubber fenders are made from a blend of polymers.
Most common polymers are natural rubber (NR), which is sourced in the form of latex from rubber trees and styrene-butadiene rubber (SBR), a synthetic rubber which is derived from petroleum by products.
Using NR- and SBR-only compounds is not recommended.
???? SBR in its pure state is less sticky and has a higher density and glass transition temperature than NR. It also has a lower modulus and tear resistance and needs additional reinforcement. NR, by contrast, is already well-reinforced by nature. Thus, rubber compounds with either NR or SBR as the only polymer have strong limitations, and therefore the industry usually uses blends of NR and SBR to harness the advantageous properties of both:
▪️ good abrasion resistance
▪️ high resilience
▪️ good aging stability
▪️ reinforcement
The choice for – and the amount of – NR or SBR in the blend determines the amount of other components to be added to improve the properties of the compound, the best-known ones being carbon black (CB) and calcium carbonate (CC).
Are you interested to learn more? Download our free White Paper on Compounding.
more closeCarbon Black (CB) is a well-known active filler which reinforces the rubber compound and has positive effects on physical properties such as tensile strength, tear resistance and abrasion resistance.
The key ????is that an improvement of the properties is tied to the right use of the material.
1️⃣ A rubber compound which consists of more Natural Rubber than Synthetic Rubber needs a lower orcement, as Natural Rubber is already well reinforced by nature – less CB is needed. *???????????? ???????????????? ???????????????? ???????????? ???????????????? ???????????? ????????????????*
2️⃣ If too much Carbon Black is used in the compound, the result will be a decrease in properties (see diagram below). The decrease results from overloading the compound with CB as there is not enough rubber left in the compound to disperse it. *???????????????? ???????? ???????????? ???????????????????????? ????????????????????????*
3️⃣ The grade and particle size of Carbon Black plays an important role for the compound quality. Smaller particles have a larger specific surface area and therefore a higher ability to react with the other components in the rubber blend. *???????????????????????????? ???????????????????????????????????? ???????????????? ???? ????????????????????????????????????????*
more closeIf something goes wrong here, the entire waterfront design could be at risk. We support our clients with our free Berthing Energy Calculation Tool.
⏬ Our tool considers all relevant parameters such as ship type, berthing mode or point of contact from bow, amongst others, and also offers the option to choose among different design methods, addressing the particulars of your project and or region.
The results should be seen as a guideline only. The list of suitable fender units based on the calculated energy is long, but typically there are only a few types and combinations that would work properly for your specific project. The subsequent step of choosing the suitable fender type and size should only be done together with an experienced fender manufacturer. Each project is unique, so our experts analyze every condition in detail to design the most suitable fender system. ????
Our experienced and highly skilled colleagues all around the globe are value engineers, in a sense, creating solutions that are ideal for our clients and on-site conditions.
more closeTest Presses
Type Approval Testing
Fundamental Testing
Physical Property Testing
Edge Distance
It is important that the load case for the fender panel is specified exactly but more important: realistically.
Case ①
A vessel contacts the steel panel with its full flat hull – the panel works as designed.
more closeIt is important that the load case for the fender panel is specified exactly but more important: realistically.
Case ②
A vessel with beltings imparts a double contact. As the panel is not designed for this load case – the steel panel could get severely damaged and might need replacement.
more closeIt is important that the load case for the fender panel is specified exactly but more important: realistically.
Case ③
A vessel with beltings imparts a line load onto the panel; this concentrated load case is so severe, that the panel might break in the contact area.
more closeUsing a fender system for a load case other than specified, not only implies monetary consequences for the terminal operator and costly downtimes until it is replaced, but also a safety risk.
The three examples of load coases show in an easy but impressive way the consequences to a fender steel panel when the actual load case differs from the specification (for more information, check the posts from Part I-III).
Be informed about the anticipated load cases to avoid damages, unnecessary cost and safety risks.
Our colleagues around the world are experts in their field and happy to discuss any questions with you.
???? You can reach them via or our contact form.
more closepneumatic fenders are common ship accessories in the maritime industry. But if you don’t understand the maritime industry at all, you will think “what is this strange thing?” at first sight. This is normal. I didn’t even know that there would be this thing on the side of the ship before I started working. There was even a joke on the beach of a certain country.
The pneumatic fender is a kind of buffer, also called Yokohama fender, because it was invented in by a rubber product company in Yokohama, Japan. The interior is filled with high-pressure air. It can be easily deflated, so that it can be easily relocated and re-commissioned. The pneumatic fender is used to absorb the kinetic energy of the ship docking, dock wall or ship docking. Fenders can be applied to all types of ships from cargo ships to cruise ships, ferries and private yachts, and can prevent damage to ships and berthing structures.
Learn more about the history of Yokohama fenders
The size of the inflatable pneumatic fender has a set of standard sizes, which is specified in the industry production standard ISO. Determine the size of the pneumatic fender according to the existing common ship size. pneumatic fenders have 12 standard diameter sizes and 13 standard length sizes. They form 17 standard pneumatic rubber fender standard sizes through different combinations. The diameter range of the pneumatic fender is 0.5m~4.5m, and the length range is 1m~12m. Commonly used sizes in ship-to-ship operations are 3.3mx6.5m and 2mx3.5m.
Nowadays, many end users have special size requirements, and most manufacturers can customize non-standard size pneumatic fenders according to customer requirements to meet the special needs of users.
pneumatic fenders are mainly used to block collisions with ships. It can greatly deflect and reduce berthing energy without causing permanent damage to the hull or concrete of the berth. Yokohama fenders are very suitable for the requirements of short-term ports of call, maritime cargo transfer, buoyancy assistance, and double berthing of ships. Use chains and shackles to be installed on the pre-installed base of the dock to make the fender float horizontally on the shore to adapt to the berthing of the boat under the changing water level of the tide.
Yokohama pneumatic fenders can also be installed on the side of the hull to prevent collisions between two ships during docking operations at sea. This kind of operation is also known as STS, which is more common in the handover of liquid cargo at sea. Sometimes ships need to do double berthing operations, that is, a ship is moored in the port, and there is another berthing method on the outside with the moored vessel. This berthing method can be quickly and effectively transferred Cargo improves the efficiency of cargo transshipment at the terminal. Pneumatic fenders are indispensable anti-collision equipment in double berthing operations of ships.
In addition to the most basic method of use, pneumatic fenders can also temporarily provide buoyancy for the vessel, preventing the vessel from bottoming in some shallow water depths.
The price of an pneumatic fender depends on its production process and materials. Different production methods have different costs, and the cost gap between the materials used is also very large. There are two main production methods for pneumatic rubber fenders, one is the mold type and the other is the winding type. Molded inflatable pneumatic fenders have no connection points and are integrally formed pneumatic fenders. The winding type is manually wound layer by layer with rubber sheets. Both have their own advantages and disadvantages. The production of winding fenders does not require the production of molds, so a part of the mold costs are saved. So the price is relatively cheaper.
The rubber material used in the pneumatic fender has purity requirements, and the impurities in the material shall not exceed the prescribed standards. Some manufacturers will stick to the upper limit of impurities to purchase inferior rubber materials, which can effectively reduce their production costs, so they can be sold very cheaply. So if you find that the price quoted by the other company is many times cheaper than the other company you asked for, then you have to be careful about whether there is a problem with the quality of their products.
As a manufacturer and supplier, we understand the buyer’s desire to buy high-quality products at a low price. However, in a rational analysis, cheap products must cut production costs, and product quality cannot be guaranteed. Sunhelm purchases pure natural rubber sheet materials with very few impurities. We don’t want customers to receive products that are too poor in quality and lead to low safety, so that the whole process is unpleasant to use。So even if the price of other manufacturers in China No matter how low it is, we will not compete with them for low prices. Sunhelm always believes that you get what you pay for, resists unhealthy low-price competition, and hopes to bring true high-quality, cost-effective pneumatic fender products to compatriots in the maritime industry all over the world.
After reading the introduction of this article. Do you know more about pneumatic fenders? If this article solves your question, you can share it on Facebook, LinkedIn, and other social platforms for more people to see. If you are interested in our pneumatic fender products, you can send us an to request a quotation.See you next time!