Foam-filled Fender

If you look into the components of a foam fender, it consists of an internal steel core, closed cell foam, reinforced cord layers, and then an outer elastomer skin.

The outer elastomer skin is usually made of the anti-corrosive PU (polyurethane).

In general, for marine use, the ‘closed cell foam’ used in these fenders are usually materials like EVA (Ethylene-vinyl acetate) or PE (Polyethylene).

EVA foam is quite an environmentally-friendly plastic packaging material, relatively new.

PE foam is a high-molecular low density foam material.

Foam fenders in marine application are usually either EVA or PE foam.

Both materials are first and foremost, anti-water absorption. Which means they do not absorb water, making them perfect for marine use. Besides, both generally provide efficient energy absorption, good chemical corrosion resistance.

Weight to absorption ratio are both reasonably good, hence their usage as fenders. If the weight is too heavy, they would be hard to deploy.

It has good moisture insulation, cushioning, chemical corrosion resistance, etc., and it has no water absorption.

Yokohama-type Pneumatic Rubber Fender

Pneumatic fenders are made of rubber and strengthening cord layers.

These are inflated to absorb collision energy during berthing.

Similar to foam fenders, these rubber floating fenders are also relatively light (for its size), and provide great cushioning due to its pneumatic properties.

To compare the two, we have to look into different aspects of their usage:

I. Performance

Performance wise, some claim that foam fenders is more efficient in terms of energy absorption. There are reports of foam-filled fenders that absorb 40% more energy than pneumatic fenders.

However, performance of foam fenders really depends on the manufacturer.

We have heard cases of customers using foam fenders that deformed easily during operation. Once deformed, the fender is not suitable for use any more. Not only the energy absorption is not efficient, it may even damage the vessels or harbour.

Therefore, it is important to not blindly assume that all foam fenders are better in performance. It is better to check and order from a manufacturer with a strong track record of delivering great products.

At MAX, our foam fenders have been used for various projects globally in countries in more than four continents.

If you require a foam fender solution, contact us today!

II. Durability

Durability is harder to gauge.

Do you define by useful life?

This is not an accurate benchmark as the conditions of deployment (working conditions) and usage rate is not taken into account.

However, one obvious advantage a foam-filled type has over a pneumatic rubber fender is that they do not deflate.

Foam fenders do not deflate. Ever.

When Yokohama-type pneumatic fenders got punctured, they fail to perform any more. Whereas for foam fenders, they would still be able to be deployed, albeit having much less efficient energy absorption.

At the very least, they could still be used sparingly for temporary purposes.

MAX pneumatic fenders generally last more than 8 years, similarly with foam fenders. Do note that however, the external hot-dip galvanised chain and tyres net would have to be changed in 2-3 years interval to ensure their integrity.

III. Maintenance

Both foam-filled fenders and pneumatic fenders require minimum maintenance.

Regular visual inspection is a must for both fender types.

For pneumatic fenders, just add in the air addition regularly (probably around 12 months).

Nevertheless, both are low maintenance equipment if you purchase from the right manufacturer.

So in this area, it can be said it is primarily a tie, with foam fender a slight edge over pneumatic.

IV. Price

This is where rubber floating pneumatic fenders have a considerable advantage over foam fenders.

For the same size, foam-filled fenders may cost up to 3x more expensive than their pneumatic counterparts.

This is because pneumatic fender’s primary component is air, which is essentially free.

However, the outer layer that holds the air has to be strong enough to efficiently absorb energy upon collision and transfer it to the air, while repelling the excess energy back as reaction force.

On the other hand, for foam fenders, it is the ultra-efficient closed-cell foam core that absorbs fully the energy (repel the excess energy back as reaction force). Hence, the amount of materials used is much more than the rubber, for a similar sized fender.

Conclusion

When determining whether to use pneumatic type or foam-filled type for your floating fender needs, it is important to consider your budget as well as expectations.

Generally smaller sized fenders like for those below diameter 2.0m, foam fenders are still at a manageable cost that still provides slightly more superior performance.

However, for jumbo sized very large-sized fenders, the costs will increase to a much bigger value. That is when most consider using pneumatic rubber fender for large ship-to-ship berthing operations.

What exactly are marine rubber fenders? For the ordinary person, it may seem weird to have so many weird-looking shapes hovering beside a port or harbour, unclear of what they are for. Even when a person is able to speculate the use of these usually-black structures is to be the “bumper” for ships to berth against, many do not understand the implications and why they come in various shapes, with some being really unique designs. Besides, many thought that the use of old rubber tyres are enough to absorb collision for berthing.

However, the berthing force is not to be underestimated. Depending on the speed, a medium-sized ship is able to destroy the dock if there are miscalculations or if the energy is not efficiently absorbed by the “bumpers”. Or worse, if there’s no fenders to absorb the collision.

Ships coming into contact directly with the quay wall or shore is no joke, look at how much damage they can do in these compilation videos:

Imagine ports/harbours without marine fenders to absorb berthing collision, quite a scary thought right?

Since ocean is the most cost-efficient transportation in the world, (Yes, it still is) there are hundreds of thousands ships, of all sizes and kinds, around us. From the use of fishing vessels, to bulk carriers, to container vessels, there are a lot of ship types out there that need reliable “bumpers“.

For years, we used timber, old tyres etc. Until so much innovation in this area that our ships slowly got bigger, faster, and becoming these mega monster-sized structures that transport your daily products made from another side of the planet. But as ships got bigger, the old timber and tyre structures just aren’t strong enough to absorb efficiently. We needed a better solution.

That is why marine fenders were invented. And it still is constantly under innovation to be more efficient, strong, and able to cope with the new ship designs. That is why you see them coming in all types of sizes, shapes and some of them complement others perfectly when used together.

A good marine rubber fender system is able to absorb collision energy at an effective and efficient manner during berthing. This helps to prevent vessel and structural damage.

Despite high budgets allocated to develop fender systems, some companies neglect some of the details that may compromise the whole structure.

Some of these cases even witness the increase in maintenance costs and accident risks due to poor performing rubber fender systems.

Just a well installed cylindrical-type rubber fender that offers protection against the quay wall

The list starts from the most obvious areas a fender system may go wrong, to the slightest details in the structure most often overlooked.

1. Rubber Fender Body Quality & Material.

High quality fenders generally absorb energy effectively and produce low reaction force.

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A high performing rubber fender system generally has high energy absorption and low reaction force. This relies on the manufacturing quality and the quality of raw materials used. This is often the top of the list when it comes to marine fender purchasing decisions.

For example, cell-shaped fender body has great energy absorption capacity

2. Types of Fenders

Inappropriate use of rubber fender types will cause the system to under perform.

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There are many different types of popular fenders. Type of fenders used are basically dictated in a project by project basis to optimise performance over the product lifecycle. Some of the most popular types are arch fenders, cylindrical fenders, supercell fenders, cone fenders and more. Different types of rubber fenders are more suited for different situations and uses. To find out more about the types of fenders, you can read our previous post HERE.

3. Fender Panel Design, Surface & Thickness.

Take fender panel thickness, material design and surface type into consideration.

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These fender panels have to be able to withstand shearing, bending and local buckling. If the designed fabrication is unprofessional and done by unqualified engineers, chances are the rubber fender system would under-perform and have a shorter life span.

The thickness of the steel plate sections and whole panel should also be considered. Many people overlook the thickness of the panel and favor the cheapest option. Yet thin panels may not be fit for the job of absorbing collision for your structure, subsequently risking the safety of port staff. Face pads’ thickness varies from 30mm to 40mm usually. Depending on usage, you would probably want to opt for 40mm as theoretically you may get near twice the service life due to higher wear allowance. The quality of paint coating is also another design detail that most people overlook when it comes to quality of the marine fender system.

4. Fender Fixings.

Fender Fixings quality are often overlooked. And it causes the system to under perform.

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The quality and materials used for fender fixings are often overlooked. The best quality fixings uses steel. It is however, also possible to use galvanised mixed materials. Depending on the usage, environmental features and expected lifespan, both are actually possible options. However, it is important not to overlook this area when making purchasing decisions.

5. The Need for Restraint Chains

The need of chains are the No.1 overlooked aspect of a rubber fender system.

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You may have noticed that not every rubber fender system requires chains. However, it is important to not forget about them when you really need these chains, for cases like when heavy panels that can not be comfortably supported by the fender alone. In some cases when chains were needed but not installed, the fender system fails in delivering and was damaged in action. Chains included should be regularly maintained as well.

These are just some of the most overlooked details when it comes to developing an effective marine rubber fender system. Most importantly, be sure to find a trusted supplier for your rubber fender system that assures you their priority. Certification from third party professional bodies is a very important aspect that assures great quality. MAX manufacturing facility is certified by various bodies like Bureau Veritas (BV), China Classification Society (CCS) and Quality Assurance Centre (QAC) just to name a few.

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Do you experience a short lifespan for your marine equipment/products? Deal with a supplier who is slow in responding and service? Or did you pay extremely high prices for an average quality product that fail quite often? 83% of our global clients claim that these are the problems that made them search for a better alternative and subsequently worked with us since.

MAX is known for our products’ great quality-to-price ratio and responsive customer service. What’s more? From our sales office to manufacturing plants, we are committed to do our part in ‘Going Green‘ for the environment. Drop us an email and we will assist!

Learn about MAX Rubber Fender Products.

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Pneumatic Fenders

These Yokohama fenders are popular in STS (ship-to-ship) usage.

Body Construction

The basic body construction of a pneumatic rubber fender consists of an outer layer made of rubber, cord layers and inner rubber layer vulcanised together. End flanges are available at both ends for air charging purposes. The outer rubber layer is made of strong rubber material to withstand external forces and protect the other layers from abrasion as well as hard usage on bad weather conditions. MAX cord layers are innovatively designed at ideal angles to evenly distribute the stress acting upon the fender. Integrative twine technology and polyamide fiber with high tensile stress are applied to provide strength and hold the internal pressure during usage. This helps distribute the stress uniformly, maintaining the energy absorption and increasing its efficiency. The inner layer is tasked to seal the air inside, minimising the air leakage using a material with airtight qualities.

Main Types of Protective Net

Pneumatic fenders can come without a protective net and is usually black in color. Colors can be changed according to client needs and MAX usually has 3 types of protective net that enhance the shelf life of the products.

(i) Tire-Chain Net

(ii) Rubber Mat-wire Net

(iii) Fiber Net

Advantages of Pneumatic Fenders

A sneak peak of what to expect: (Click to Enlarge)

Advantages during inclined berthing

During berthing, the initial contact with the dock is usually at an oblique angle and that places a lot of pressure on both surfaces (the dock and the ship).

For typical solid rubber fenders, at inclined compression which is usually the case, energy absorption decreases considerably. Therefore, it is not unusual to see solid fenders used are larger in sizes. On the other hand, pneumatic fenders’ energy absorption maintains at a relatively high level despite inclined compression. Due to a more evenly distribution of load pressure, the torque performance against the dock is usually smaller when compared to conventionally designed solid fender systems.

Stronger against shearing force

After making contact with the dock, the vessel is usually slowly moved to the optimum mooring position. This action exerts high shearing force and compression on the surface of fenders. Most solid fenders are severely damaged due to such forces as they are not designed to withstand strong shearing forces and friction that way. However, it depends on the designs/types of solid fenders. For example, MAX frontal pads for solid fenders are designed to tackle this issue and protect the fenders from shearing forces, in which the surface of fenders do not make contact with the ship.

Relatively safe even during excess load

Generally speaking, all fenders should be used within the impact load limit. However in real life situations, it is common to see that fenders often accidentally receive excess loads. When that happens, the fortunate thing about a pneumatic fender is that the reaction force does not increase sharply under excessive load. In contrast, solid fenders’ reaction forces tend to spike sharply under excessive load conditions and damage the ship during the mooring process. This is also helped by pneumatic type fenders’ characteristic that enables a more uniform distribution of stress.

Advantages during crucial weather conditions

During crucial weather conditions when the wave action is severe, mooring processes are further complicated due to up and down unbalanced action at the quay. This exerts a higher shearing force on the fenders and the frequently change in forces during mooring under such weather conditions will cause fatigue on typical solid type fenders. However on the other hand, pneumatic fender’s flexible contact area and large allowable deflection characteristics minimise fatigue during such situations. In fact, for seas with rough situations or frequent bad weather conditions, pneumatic types may be a better option than solid type fenders as it may display a longer life span.

Deterioration in performance minimised

Aging and fatigue often cause fenders to deteriorate in terms of performance. However, due to its air filled body and highly elastic material, such issues are minimised. Solid rubber fenders or foam fenders depend more on the hardness of the material and such dependance may result in decrease in energy absorption performance after years of usage and temperature change. On the other hand, as long as basic maintenance and air pressure control is maintained, pneumatic fenders remain optimum performance even at extremely low temperature down to -50 Degree Celsius or even during high fluctuations.

Tide adaptation

Pneumatic fenders are primarily floating-types, which means the fenders float on the water in an unrestricted vertical plane corresponding to the tidal range and ship’s vertical movement. Therefore, fender energy absorption always take place at the most optimum position.

Simple installation and low maintenance cost

Pneumatic fenders can be installed simply by means of ropes or chains at minimal extra cost. Transfer or removal is also really flexible and easy for such floating type fenders. Maintenance for pneumatic type fenders include annual checks on internal air pressure, physical condition of the chain net and fender surface. Usually chain nets have a life span of about 3 to 4 years, depending on usage.

MAX Produced Pneumatic Fenders

To learn more about MAX pneumatic type fenders, visit our ‘Pneumatic Floating Fender‘ product page.

Tug boat fenders are high abrasion resistance rubber fenders used to protect the vessel and the other surface during contact. Boat fenders are also known as boat bumpers, rubber fenders and marine fenders. For starters, tug boat is a type of boat that maneuvers vessels by towing or pushing them. These boat fenders possess excellent resilience properties and is highly durable due to its great sea water resistance. Port owners and tug boat owners are definitely very familiar with such boat fenders as it absorbs the energy during contact and protects the both colliding surfaces.

4 Most Popular Types

Tug boat fenders can actually be categorised into 4 main types where each serves a different application. The type and number of fenders depends on the size and arrangement of the tug boat itself.

Cylindrical Tug Fenders

Cylindrical type of rubber fender is commonly used as the primary fendering system fitted to the bow or stern of tug boats. Usually a longitudinal support chain runs down the centre of the fender, supported by straps and chains fitted into grooves. Sizes varies according to the vessel size.

These fenders are used to push against flared hulls and its shape is flexible for ship-to-ship (STS) operation with different types of vessels in open sea conditions as well.

Block Fenders

Block fenders are also known as cube boat bumpers for some. Mainly preferred for their great grip as a result of balanced grooved surfaces. This traditional shaped fender has a large contact surface that results in low hull pressures, making it even more suitable for heavy-duty applications. An optional UHMW-PE face is mostly available.

Tugs that operate in heavy swell and storm conditions therefore prefer block boat fenders most of the time.

M – Fenders

M-Fenders are installed to the bow and the aft part of tug boats to protect the vessel from damages during operation. The fenders’ large flexible surface area that minimises the pressure acted upon the vessel during pushing and pulling operations can be fitted around tight curves. Similar to block fenders, M-shaped boat bumpers provide extra grip with their grooved surface while the triple “legs” acts as a strong attachment to the vessel.

M-shaped rubber fenders have a relatively low weight and this attribute contributes to a better tug stability. Due to its heavy duty design and strong attachment, M-shaped is one of the most popular rubber fenders.

W – Fenders

W-shaped Fenders have an extreme-duty design that is for even the most extreme operating conditions. It is definitely one of the most commonly used boat bumper for tugs today. Fenders can be installed around the curves of most hull shapes and effectively buffer the collision between docks and ships. Tensile strength is highly customisable according to client’s requirements.

Ocean-going tugs and large harbor tugs are the most common applications for W-fenders.

BONUS: D-Fenders

D-shaped fenders are are also commonly found on tug boats. But they are usually specified with their signature “D” shaped and comes with different bores.

Trustworthy supplier to avoid costly mistakes

An effectively designed and efficient fender will save you a lot of money and time as it provides maximum protection to your docking surface and the vessel. A poorly designed fender and cheap raw materials will affect the energy absorption and reaction force that acts upon both surfaces. MAX Groups Marine has been supplying high quality fenders for decades and we take pride in our quality as well as customer service.

View our Tug Fender product page.

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Marine fender is a kind of marine equipment to protect ships, vessels, boats etc during contact against the various things like piers, docks and wharves.

Marine fenders are often known as marine bumpers too. This is an equipment that is of much significance due to the prevention of damage to both the vessel and the other surface.

The fender equipment is employed in a system or structure for the vessel so that the head or the hull of ship / boat can be protected when there is an occasion of collision. This equipment can also be found on docks, piers, wharves and port structures. There are various varieties of it catering to different functionalities and they come in different shapes.

Some of the most popular ones include:

Cell Fenders

Cell fender is one of the most reliable, proven fender design and arguably the most commonly used structure in the maritime industry.

The fenders are the often used in oil and LNG platforms, offshore terminals, container berths and others. These are the kind of marine fenders that can deliver high performance and be ultra durable.

The shape of it provides it with the shear resistance and sturdiness, equipped with the capacity for absorbing energy in an equal manner from different directions and compact structure.

Cone Fenders

This is the kind of marine fender that can be considered as an improved version that of the cell fender.

This fender is suitable for handling with various different situations due to its highly efficient geometry.

Its application can be in those sites with much difference in the tidal variations. The advanced features of this fender can be helpful in improving the capabilities of vessel cranes in material handling.

Cone-type fender can easily get deflected due to its shape and can be capable of absorbing energy from various directions. Thus making it very stable despite large compression angles.

MAX Product- Marine Cone Fender

Pneumatic Fenders

These are fenders that are used mainly for the purpose of transfer from one ship to another at the mid seas, or what we commonly call “STS” operation.

Pneumatic fenders require minimal maintenance cost. Another special feature of this fender is the lower reaction force at the time of lower deflection (soft reaction force).

This property makes these fenders very suitable for Ship-to-ship (STS) operations.

Usually a tyre/chain net can be fitted on pneumatic fenders to offer extra protection.

Arch Fender

This is the kind of marine fender that is a simple design that provides excellent shear performance.

The sizes of an arch fender varies according to requirements.

This type of fender is suitable for vessels with high allowable hull pressures due to its design.

Its popular application includes general cargo vessels, workboat harbors, barge berths and more.

These are just some of the most popular marine fenders in the industry. Depending on the requirements, application and restrictions, different types appeal to different cases. For more info of the different variations/types of marine fenders, you can read an article about fender types & things to note.

Rubber Fenders: Types & Things to Note

Rubber fenders are primarily used as “bumpers” to absorb collision energy during contact between the vessel and docks (or even other vessels) in the maritime industry. For many, they might not be aware that massive sea vessels are embedded with rubber fenders on the outer surface of the vessel. These fenders are also known by some as rubber buffers. Rubber fenders are also installed on docks.

The primary objective of the rubber fenders on the dock is to absorb collision energy during the berthing process. This in return protects both the ship and the dock after collision. Solid rubber fenders have been used for ages since they are readily available and are considered long lasting. Rubber fenders come in different forms including, pneumatic type, CO-type, SC-type, GD-type and many others. All these types of rubber fender are unique in their own way and come with different specifications and uses as discussed below.

Popular Types of Fenders

Pneumatic rubber fenders: they are considered as the leading anti-collision devices for marine applications. They play active role as protective medium against collision in ship-to ship contacts (STS), and ship-to-berthing. Their biggest advantage is that they absorb massive energy with low unit surface acted on upon the ship. They are additionally used in rapid response and emergency fendering, on tankers, gas carriers and bulk cargo ships. As a standard measure, they are manufactured with an ISO certification and are available in various sizes.

Super cell rubber fenders: These are also known as SC rubber fenders. Its major features include low reaction force with a high capacity of energy absorption. They have also been rated as long lasting and more preferably used on the sea docks.

Cone rubber fenders: Also referred to as Type CO fenders, they endure severe shear external force by making effective use of its conical body shape. With its high elasticity levels they are more often used in big port construction.

“Wing” DO Rubber fenders: An improved design derived from the original D-Fender, this shape offers greater stability and maintains high durability. It can be found on boats, marine assets, floating structures etc. It is not a very popular option compared to other fender types, but it does what it does well. They are also used in the general framework in wharf.

Foamed filled fenders: these fenders are also very often used in ship-to-ship and ship-to-quay berthing operations. They are used as alternatives to the normal pneumatic fenders. Their unique characteristics include, high energy and low reaction states, they are unsinkable even when ruptured and have a high degree of wear resistance.

Arch type: Even with a simple design, arch fender provides incredible shear performance, making it suitable for vessels with high allowable hull pressures.

Unit Element Fender: One of the most durable type with a versatile modular system. It can be installed horizontally or vertically on quay walls to suit a particular use.

Cylindrical type CY: Cylindrical shaped fender offers great versatility to accommodate all sizes of ships makes it a one of the most commonly used marine fender system. One unique advantage over other types is its ability to be installed diagonally, in addition to vertical or horizontal fitting.

“D” type fender: There are 3 main types of “D” rubber fenders with differences in the inner hollow shape. DD comes with a D-shaped inner hollow; DC comes with a O-shaped inner hollow; while Solid-D is entirely solid. These fenders are popularly installed on smaller port walls and on boats/small ships.

Square-shaped: In short, they are best used for tough and demanding environment. Designed to operate under harsh conditions, they display great shear resistance and incredible durability. Two popular types of such square fenders are those with an O-shaped hollow or D-shaped hollow. Though relatively uncommon, some do request for a solid piece without the hollow in it. 

“Keyhole” version: The outlook of the keyhole fender looks quite similar to the square type fender. The hollow part in the middle is of a key-hole shape. Depending on requirements, it can come with UHMWPE pads, or have a grooved/flat surface. It has high resistance towards abrasion and UV.

“Roller” type: Specifically designed for entrances of docks and narrow canals, the roller design facilitates ships into space-restricted waters, by avoiding the vessel from crashing into the walls. Its main function is not about energy absorption, instead its main function is to “guide” the vessel. We have seen even wheels be utilised as rollers.

Cylindrical tug fender: Different from Cylindrical CY-type, the cylindrical tug is often found on the bow and stern of tug boats. Its semi-flexible body enables a well-fitted installation, making it one of the most popular option for boat fenders.

“W” version: Another popular choice for tug boats due to its ability to fit the form of the boat stern/bow.

“M” version: M-Fender has a wider contact surface area than W, making it a great choice to protect the tug surface when performing “push” operations.

Things to Note when Choosing Marine Fenders

When considering acquiring fenders, several factors should be considered. The fenders’ quality in terms of high energy absorption and low reaction force, as well as a reasonable structure that provides a long life span. The quality of raw materials used, in this case, rubber should also be considered. High quality products will have a longer shelf life, thus, more cost-effective.

Besides the quality of the product itself, the fenders should have an easy set of installation options or the supply company would provide professional installation service. For example in MAX Groups Marine, we either send our installation team to take care of the installation or educate our customers on the procedures and things to note. It is our promise to not only ensure proficiency in the marine fender application, but also add value to vessel owners and dock holders.

MAX Groups Marine has been supplying solid rubber fenders and pneumatic fenders for more than 12 years. Our pneumatic fenders’ manufacturing process is especially innovative as we use molding technology unlike most other factories who uses traditional manufacturing. Our products therefore has a much smoother surface and longer shelf life. Learn more at about our pneumatic fenders HERE.

More info on MAX Solid Fender products HERE.

Read more about Marine Fenders at Popular types of Marine Fenders and Their Functionalities
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