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The History of Yokohama Fenders / Pneumatic Fenders

These type of fenders are the #1 option for STS operations, world-wide.

Tankers’ Ship-to-ship (STS) operations mostly uses this type of self-floating, long useful life fender. Industry-wide known as pneumatic fenders, but why are they also called Yokohama fenders by many?

This type of marine fender works fundamentally different than the solid rubber type fenders. These use pressurised air to absorb collision energy – based on principles of pneumatics.

They are (relatively) light and easy-to-deploy. Good quality ones can be used for a very long time. These floating fenders have many other types and advantages.

In this article however, is to discuss a lesser-known aspect of this popular equipment in maritime.

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Where did the idea come from? And when?

Short answers: Japan. After World-War II.


So, Why are they commonly referred to as ‘Yokohama Fenders’?

Yokohama was the first company approached to design such a fender. Hence, the name.

The traditional way was to find and use dead whales as large fenders for bigger ships. After the World-War, many turned to find a better, more constant man-made equipment as the usage of dead whales has many downsides to it.

Rubber was thought to be a great material. So being the most trusted rubber tyre manufacture in Japan at the time, the ‘Yokohama’ company was approached to design up a suitable solution.

The first big issue was that making a fender straight-up using rubber would be too costly. Let’s take for example, a size of a pretty standard diameter 3.3m x 6.5m size fender today. Theoretically that would need >70m3 of rubber material. The projected costs made it unfeasible.

The company managed to eventually come up with the idea of using the principles of pneumatic. Pressurised air absorbs energy well enough with a reasonable reaction force.

Today, commonly used working pressures of pneumatic fenders are 50 kPa and 80kPa.


Historically, yokohama fenders was not the only man-made solution

For decades, these floating fenders were not the only ones used during mooring.

They were used in conjunction with some wheel-shape fenders and many smaller-sized secondary fenders. Those small secondary fenders were said to be used to protect the stern and the bow from unexpected contact. Wheel type fenders were used at further outs while the yokohamas were used in inner areas along the midbody.

Fenders were usually secured to the ship that’s manoeuvring.


Yokohama type fenders today

The story of the origin of these fenders is indeed a very interesting development of the industry.

Today, these awesome low-cost, low-maintenance fenders are governed by ISO Standard ISO17357:2014.

ISO 17357-2:2014 specifies the material, performance, and dimensions of floating pneumatic rubber fenders

Throughout the years, there are many manufacturers that strive to develop the technologies and manufacturing capabilities. In this era, other manufacturers seem to be catching up in delivering high grade, long useful life “yokohama-type” fenders as well.

pneumatic-fender-yokohama-types-advantages


What are marine fenders? Are they important? [with ship crash videos]

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.


rubber-fender-damaged

5 Ways a Rubber Fender System can Fail You. #4 is the Most Overlooked Mistake.

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.

5 ways fenders fail and fender maintenance

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

Cylindrical-fender

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.

MAX Product-Solid Fender 12

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.

MAX Product-Solid Fender 8MAX Product-Solid Fender 13

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.

MAX Product-Solid Fender 14

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.

MAX Project Vietnam 1

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.

Drop Us an Email!

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 : Types & Advantages of Application

MAX pneumatic fender header

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.

MAX pneumatic fender construction

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

tire-chain net fender

(ii) Rubber Mat-wire Net

rubber mat wire net

(iii) Fiber Net

fiber net

Advantages of Pneumatic Fenders

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

Advantages of MAX Pneumatic Fender

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.

pneumatic fenderpneumatic fenders advantage


tug-rubber-fender

4 Types of Popular Tug Boat Fenders

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.

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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.

MAX Product-Solid Fender 7

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.

 block boat fender

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.

m fender tug boat bumper

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.

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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.

MAX Product-Solid Fender 9 D Fender

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-functionalities

Popular types of Marine Fenders and Their Functionalities

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.

Cylindrical Fender 3 MaxArch Fender 4 Max

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.

MAX Project Vietnam 2super cell fender max

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-Solid Fender 4

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.

pneumatic fenderpneumatic fender

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.

MAX Product-Solid Fender 8Arch fender max

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.


marine-rubber-fender-types-note

Rubber Fenders: Types & Things to Note

MAX rubber fender image

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.

super cell fender maxArch Fender 4 Max

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.

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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.

MAX Project Vietnam 2MAX Product-Solid Fender 12

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.

MAX Product-Solid Fender 4cone fender installation

“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.

 wing fender DOGD Fenders marine

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.

MAX Product-Solid Fender 11portable foam fender

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

MAX Product-Solid Fender 8Arch fender max

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.

max Unit Element FenderUnit element fender max project

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.

max cylindrical fenderCylindrical fender max

“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.

D fender maxmax extrusion fender

Square-shapedIn 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. 

square fenderssquare shaped dimensions

“Keyhole” versionThe 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.

keyhole fenderkeyhole dimension

“Roller” typeSpecifically 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.

MAX Product-Solid Fender 13roller rubber fender

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.

solid tug fendersMAX Product-Solid Fender 10

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

W type rubber fendermax marine fenders australia

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

m fender tug boat bumperM type rubber fender

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.

MAX Marine FenderCylindrical Fender 3 Max

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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defensa-yokohama

Ventajas & Tipos de Defensas Neumáticas (Yokohama)

Defensas Neumáticas Flotantes de goma, tipo Yokohama

Las defensas neumáticas flotantes de caucho son consideradas como uno de los principales equipos anticolisiones para las aplicaciones marinas. De acuerdo con la norma ISO 17357: 2002, las defensas neumáticas flotantes de goma en ocasiones son denominadas de forma coloquial como “defensas Yokohama” o “defensas tipo Yokohama”.

Juegan un rol activo como medio de protección contra las colisiones en las operaciones de contacto de barco a barco y de barco a embarcadero. Su mayor ventaja es que absorben una gran cantidad de energía, con baja presión en superficie de la unidad sobre barco. También se utilizan como defensas de emergencia, en buques petroleros, gaseros y barcos de carga a granel.

marinas defensas de goma

Composición

La composición básica de las defensas neumáticas de caucho consiste en una capa externa de goma, capas de cuerdas y una capa interior de caucho vulcanizadas juntas. Las bridas de los extremos están disponibles en ambos extremos para propósitos de carga. La capa de goma externa está hecha de material de caucho fuerte para resistir fuerzas externas y proteger a las otras capas de la abrasión, así como para uso rudo en malas condiciones meteorológicas. Las capas de cuerdas están diseñadas de forma innovadora en ángulos ideales para distribuir uniformemente la tensión que actúa sobre la defensa. Se aplican tanto la tecnología de entramado de cuerdas como la fibra de poliamida de alta resistencia a la tensión para proporcionar resistencia y mantener la presión interna durante el uso. Esto ayuda a distribuir uniformemente la tensión, manteniendo la absorción de energía y aumentando su eficiencia. La capa interior tiene la tarea de sellar el aire que se encuentra dentro, reduciendo al mínimo las fugas de aire ya que utiliza un material con cualidades herméticas.

Composición

 

Principales tipos de redes protectoras

Las defensas neumáticas pueden venir sin red de protección y generalmente son de color negro. Los colores se pueden variar según las necesidades del cliente y suelen tener 3 tipos de redes de protección para mejorar la vida útil de los productos.

(i) Red de cadenas de neumáticos

tire-chain net fender

(ii) Red de alambre de caucho

rubber mat wire net

(iii) Red de fibra

fiber net

Ventajas de las defensas neumáticas

Ventajas

(Clic para agrandar)

Hay varias razones por las que las defensas neumáticas marinas son la opción preferida para muchos.

Ventajas durante los atraques inclinados

Durante el atraque, el contacto inicial con el muelle suele tener un ángulo oblicuo y pone mucha presión en ambas superficies (la del muelle y la del barco).

En las típicas defensas de goma sólidas, al tener una compresión inclinada, la absorción de la energía disminuye considerablemente. Por lo tanto, no son poco comunes las situaciones en las que las personas optan por defensas sólidas de mayor tamaño. Por otro lado, la tasa de absorción de energía de las defensas neumáticas se mantiene en un nivel superior incluso cuando las comprimen en determinados ángulos. Debido a una distribución más uniforme de la presión de carga, el rendimiento del par de torsión contra el muelle suele ser menor en comparación con los diseños convencionales de los sistemas de las defensas sólidas.

Mayor resistencia contra las fuerzas de torsión

Al hacer contacto con el muelle, los barcos son por lo general movidos lentamente a una posición óptima de amarre. Esta acción ejerce una gran fuerza de cizallamiento y compresión en la superficie de las defensas. La mayoría de las defensas sólidas están severamente dañadas a causa de estas fuerzas ya que no están diseñadas para resistir intensas fuerzas de cizallamiento y fricción. Ese es el motivo por el que la mayoría de las defensas marinas tienen paneles frontales para hacer frente a este problema y proteger las defensas de goma de las fuerzas directas de cizallamiento. De esta forma, las defensas no entran directamente en contacto con el barco. A diferencia de las defensas de normales, las defensas Yokohama pueden resistir altas fuerzas de cizallamiento desde todos los ángulos gracias a sus propiedades neumáticas (llenas de aire). Esto las convierte en una alternativa ideal en comparación con las voluminosas dimensiones de los marcos de las defensas frontales.

Son relativamente seguras incluso durante una carga excesiva

En general, todas las defensas deben utilizarse dentro del impacto del límite de carga. Sin embargo, en situaciones de la vida real, es común ver que las defensas suelen recibir exceso de cargas accidentalmente. Cuando eso sucede, lo fantástico de las defensas Yokohama es que la fuerza de reacción no aumenta considerablemente bajo una carga excesiva. En contraste, las fuerzas de reacción de las defensas sólidas tienden a subir marcadamente bajo condiciones de carga excesiva y dañan la nave durante el proceso de amarre. Las características de las defensas neumáticas flotantes también contribuyen al proceso ya que permiten una distribución más uniforme de la tensión.

Ventajas durante condiciones climáticas cruciales

Durante condiciones climáticas cruciales, cuando la acción de las olas es intensa, los procesos de amarre se complican aún más debido a la acción desequilibrada de movimientos hacia arriba y hacia abajo en el muelle. Esto ejerce una fuerza de torsión más alta en las defensas y el cambio de frecuencia en las fuerzas durante el amarre en tales condiciones meteorológicas ocasionará fatiga en las típicas defensas de tipo sólido. Sin embargo, por otro lado, el área de contacto flexible de las defensas Yokohama, así como sus amplias características de deflexión permisible minimizan la fatiga durante dichas situaciones. Debido a que las defensas son defensas flotantes, su rendimiento de absorción de energía se ve menos afectado por las diferencias severas en las olas de la marea. Para mares con situaciones difíciles o con frecuentes condiciones meteorológicas adversas, así como fuertes diferencias en la marea, las defensas neumáticas flotantes marinas de caucho pueden ser una mejor opción ya que suelen mostrar una vida más larga.

Deterioro en el rendimiento minimizado

El envejecimiento y la fatiga causan frecuentemente que las defensas se deterioren en términos de rendimiento. Sin embargo, debido a su composición llena de aire y que son altamente elásticas, estos problemas se reducen al mínimo. Las defensas de caucho sólidas o las defensas de espuma dependen más de la dureza del material, y dicha dependencia puede resultar en la disminución del rendimiento de absorción de energía y en cambio de temperatura después de años de uso. Por otro lado, siempre y cuando se les de mantenimiento básico y control de la presión del aire, las defensas neumáticas se desempeñarán con un rendimiento óptimo a temperaturas extremadamente bajas de hasta -50 grados Celsius, o incluso durante fluctuaciones de temperaturas altas.

Adaptación a la marea

Las defensas Yokohama son principalmente del tipo flotante, lo que significa que las defensas flotan en el agua en un plano vertical sin restricciones a la amplitud de la marea y al movimiento vertical del barco. Por lo tanto, la absorción de la energía de las defensas siempre sucede en la posición más óptima.

Instalación sencilla y mantenimiento de bajo costo

Las defensas neumáticas pueden instalarse simplemente por medio de cuerdas o cadenas a un costo adicional mínimo. En este tipo de defensas flotantes, la transferencia o remoción también es muy flexible y fácil. El mantenimiento de las defensas neumáticas (defensas tipoYokohama) incluye revisiones anuales sobre la presión interna del aire, inspección de las condiciones físicas de la red de la cadena y de la superficie de la defensa. Por lo general, las redes de las cadenas tienen una vida útil de aproximadamente 3 a 4 años, dependiendo de su uso.

Pneumatic fenderDefensas tipo Yokohama
Para aprender más sobre las defensas neumáticas flotantes de caucho, visite nuestra página del producto ‘Pneumatic Fender‘.

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tipos-defensas-de-goma

Defensas de Goma: Tipos & Aspectos de Interés

Las defensas de goma se utilizan principalmente como “parachoques” con la finalidad de absorber la energía de la colisión durante el contacto entre el barco y los muelles (o incluso entre buques) en la industria marítima. Muchos podrían no estar al tanto de que los enormes buques marítimos están equipados con defensas náuticas en la superficie exterior del barco. Estas defensas también conocidas como amortiguadores de goma. Las defensas de caucho también se instalan en los muelles.

El objetivo principal de las defensas marítimas en los muelles es la de absorber la energía de la colisión durante el proceso de atraque. Asimismo, esto protege tanto al barco como al muelle después de la colisión. Las defensas de goma sólidas se han utilizado desde hace mucho tiempo debido a que están disponibles fácilmente y son consideradas de larga duración. Las defensas de caucho vienen en diferentes presentaciones, incluyendo las neumáticas, tipo CO, tipo SC, tipo GD y muchas otras. Todos estos tipos de defensas náuticas de caucho son únicos a su propia manera, vienen con diferentes especificaciones y se utilizan como discutiremos a continuación.

Rubber Fender Slider 3

Tipos Populares de defensas

Defensas para barcos tipo Yokohama: Son consideradas como los principales dispositivos anticolisiones para las aplicaciones marítimas. Juegan un papel activo como medio de protección contra las colisiones de barco a barco, y de barco a muelle. Su mayor ventaja es que absorben una enorme cantidad de energía con una unidad de superficie baja en el barco. Adicionalmente, son utilizadas en la respuesta rápida y como defensas de emergencia en buques petroleros, gaseros y barcos de carga a granel. Como medida estándar, son fabricadas con la certificación ISO y están disponibles en varios tamaños.

Pneumatic Fender slider 1

Defensas para muelles super cell: Son conocidas como defensas para muelles SC. Entre sus principales características se incluye la baja fuerza de reacción con una alta capacidad de absorción de energía. También han sido calificadas como de larga duración y son utilizadas con mayor preferencia en los muelles marítimos.

Defensas para muelles super cell

Defensas de muelles super cone: También son llamadas defensas tipo CO, soportan una severa fuerza externa de cizallamiento, haciendo uso efectivo de su forma cónica. Con sus altos niveles de elasticidad, se utilizan con más frecuencia en las construcciones de puertos grandes.

Defensas de muelles super cone

 

Defensas para barcos de hule espuma: Estas defensas también se emplean muy frecuentemente en las operaciones de atraque de buque a buque y de buque a muelle. Son utilizadas como alternativa a las defensas neumáticas normales. Sus características únicas incluyen alta energía y bajos estados de reacción, no se hunden, incluso si se rompen, y tienen un alto grado de resistencia al desgaste.

flange foam fenderportable foam fender

Defensas de goma tipo arco: Incluso con un diseño simple, las defensas tipo arco proporcionan un desempeño de cizallamiento increíble, esto las hace adecuadas para barcos que se pueden permitir altas presiones en el casco.

MAX Product-Solid Fender 8Arch fender max

Defensas portuarias marinas Unit Element: Uno de los tipos más duraderos con sistema modular versátil. Pueden instalarse vertical u horizontalmente en las paredes del muelle para adaptarse a un uso particular.

Unit element fender max project

Defensas náuticas de caucho tipo CY: Defensa de forma cilíndrica que ofrece una gran versatilidad para adaptarse a todos los tamaños de barcos, lo que las convierte en un uno de los sistemas de defensas marinas más utilizados. La ventaja única que tienen sobre otros tipos es su capacidad para instalarse en diagonal, adicionalmente a un montaje vertical u horizontal.

Cylindrical fender 2

Defensas de Goma tipo D: Hay 3 modelos principales de defensas marinas tipo “D”, con diferencias en la forma de la cavidad interior. Las DD vienen con una cavidad interior en forma de D; Las DC vienen con una cavidad interior en forma de O; mientras que la Solid-D es completamente sólida. Estas defensas se instalan popularmente en las paredes de los puertos más pequeños y en botes/barcos chicos.

MAX Product-Solid Fender 9 D Fendermax extrusion fender

Defensas de goma tipo DO: Diseño mejorado derivado de la original defensa D, esta forma ofrece una mayor estabilidad y mantiene una alta durabilidad. Puede encontrarse en los barcos, recursos marítimos, estructuras flotantes, etc. No es una opción muy popular en comparación con otros tipos de defensas, pero hacen bien su trabajo. También se utilizan la estructura general en los muelles.

Defensas de goma tipo DO

Defensas marítimas de goma cuadradas: En resumen, lo mejor es utilizarlas para entornos difíciles y exigentes. Están diseñadas para operar en condiciones muy difíciles, muestran gran resistencia al cizallamiento y una durabilidad increíble. Dos tipos populares de defensas cuadradas son las que tienen una cavidad en forma de D o en forma de O. Aunque son relativamente poco comunes, algunos solicitan una pieza sólida sin cavidad.

FO

Versión “Ojo de cerradura”: La perspectiva de la defensa de ojo de cerradura es muy similar a las defensas náuticas de caucho cuadradas. La cavidad en el centro tiene forma de ojo de cerradura. Dependiendo de los requisitos, puede venir con almohadillas UHMWPE, o tener una superficie estriada/plana. Cuentan con una alta resistencia a la abrasión y a los rayos UV.

keyhole fenderkey fender

Tipo “Rodillo”: Diseñadas específicamente para las entradas de muelles y canales estrechos, el diseño de rodillos facilita que los barcos entren en aguas con espacios restringidos, evitando que el buque choque contra las paredes. Su función principal no es la absorción de energía, sino la de servir como “guía” del buque. Incluso hemos visto que hay quienes utilizan ruedas como rodillos.

roller rubber fenderroller wheel fender

Defensas cilíndricas de remolque: A diferencia de las cilíndricas de tipo CY, las defensas cilíndricas de remolque pueden encontrarse frecuentemente en la proa y popa de los buques remolcadores. Su cuerpo semiflexible permite una instalación bien ajustada, por lo que es una de las opciones más populares para las defensas de barcos.

MAX Product-Solid Fender 10solid tug fenders

Versión “W”: Otra opción popular para los buques remolcadores debido a su capacidad para adaptarse a la forma de la popa / proa del barco.

max marine fenders australia

Versión “M”: La defensa M tiene un área de superficie de contacto más ancha que la W, por lo que es una fantástica opción para proteger la superficie de remolque cuando se realizan operaciones de “empuje”.

m fender tug boat bumper

Aspectos de interés al elegir Defensas Marinas

Al consideras adquirir defensas, deben tomarse en cuenta varios factores. La calidad de las defensas náuticas de caucho en términos de alta absorción de energía y baja fuerza de reacción, así como una estructura razonable de que proporcione una larga vida útil. La calidad de las materias primas utilizadas, en este caso el caucho, también debe ser considerado. Los productos de alta calidad tendrán una vida útil más prolongada, y serán por lo tanto más rentables.

Además de la calidad del producto como tal, las defensas deben contar con un sencillo conjunto de opciones de instalación, o la empresa de suministro debe proporcionar servicios de instalación profesionales. Por ejemplo, en MAX Groups Marine, enviamos a nuestro equipo de instalación para que se haga cargo de la misma, o bien, educamos a nuestros clientes sobre los procedimientos y los aspectos que deben de tomarse en cuenta. Nuestra promesa es no solo garantizar la eficiencia en la aplicación de las defensas marítimas, sino también añadir valor a los propietarios de los buques y a los titulares de los muelles.

MAX Groups Marine ha suministrado defensas de goma sólidas y defensas neumáticas por más de 12 años. El proceso de fabricación de nuestras defensas neumáticas es especialmente innovador debido a que, a diferencia de la mayoría de las fábricas que emplea la fabricación tradicional, nosotros utilizamos tecnología de moldeo. Por lo tanto, nuestros productos tienen una superficie mucho más suave y una vida útil más larga. Obtenga más información sobre nuestras defensas neumáticas AQUÍ.

Más Información de los Productos de Defensas Náuticas de caucho MAX AQUÍ.

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Choose a suitable marine fender design system

If you are looking for a post that lists out all available rubber fender design types like “pneumatic fender”, “modular fender”, “D-shaped bumper” etc, you should visit “Rubber Fenders: Types & Things to Note” article.

chain selection

This article post aim to discuss the generally used equations, formulas, factors to determine a suitable port fender design. All formulas and equations are only intended as reference only. If you have a project, drop us an email so our technical staff can advise you.

Contributed by Wang.

Defensas para muelles super cell

A solution to absorb collision & prevent damage

Since the early days of floating crafts & small wooden boats, fenders were woven from ropes to absorb collision during berthings. Similar to the products we have today, they came in various sizes and patterns to serve different needs. The primary function of such a “soft-contact” system is to prevent the vessel from sustaining damage as the ship or boat is being moored against the quay wall. However, the vast amount of variations may confuse some looking to purchase certain fenders for their new-built port or jetty. In short, impact forces during the vessel berth, abrasive action, among other factors must be taken into consideration as well as the block safety coefficient to provide some allowance. The multi dimensional forces may cause extensive damage to the jetty structure AND the ship at the same time if a less suitable fender is used (or worse, a low performance fender system is deployed). So, it is about absorbing contact and distributing the force onto a larger surface area to prevent damage. Aside from mostly uniformly distributing collision force, it also increases impact time to lower the reaction force in whole.

Yes, it is important to have a structure of this kind to prevent damage to the quay wall or jetty or harbour.

Quite simply, determining a suitable marine fender system comes down to considering:

Amount of Energy Absorbed and Maximum Impact Force Imparted

Common Selection Process: All Conditions must be Carefully Studied

It is important to keep in mind that the local marine condition is as big a factor as the ships the quay is accomodating. Both aspects affect the choice of “marine bumpers” used. So it is not surprising to see two different types of fender systems being deployed in the same city, but to accommodate different types of ships. Harbor conditions are also rarely the same. Successful previous local experience must be considered. The best way to figure out what type of port fender is suitable for your berthing structure would be to carefully study your own local marine condition that includes:

  • Site condition and depth
  • Local temperature range & weather
  • Wind velocity
  • Direction of ship when berthing
  • Tidal range & wave height
  • Berthing structure
  • Type of ships, along with class, configuration, size
  • Velocity of ship approaching the quay wall during berthing
  • Exposure of harbor basins
  • Available docking assistance
Before diving into this guide, one has to understand that the design criteria differ from one person to another. So this article is aimed to act as jsut a reference for many. For detailed project designing & fender choosing, kindly contact a professional team to design suitable marine fender system.
Prior to designing and doing any calculations, one has to prioritise one’s design standard and criteria.
  • Are there any specific codes and standards that you need to conform to?
  • Intended useful life of product? Some fenders are longer lasting than others.
  • Safety factor?
  • Designated vessels for berthing calculations?
  • Velocity range?
  • Costs: From installation fees, to maintenance costs. All has to be thoroughly considered.

Guide:

The law of energy conversation is the basis for all fender design selection. When choosing fenders, it is vital to base calculations and considerations on the largest (heaviest) vessel sizes to be berthed at the wharf. Besides, vessels are getting larger as ship design evolves from time to time. It is important to take into consideration those expected to arrive in the near foreseeable future.

Fender Energy Absorption = Energy Delivered upon impact – Energy absorbed by pier

To understand how much energy absorption is needed, one needs to first determine the energy that will be delivered to the quay wall upon initial impact.

Secondly, one has to then carry out calculation to find out the energy that requires to be absorbed. For linearly elastic structures, the energy is ½ the maximum static load level times amount of deflection. Some allowance should be added. If the structure is very rigid, one can assume no energy absorption from the pier.

Minus the energy amount absorbed by pier and one can determine the fender energy absorption value that is required for a safe berth.

Then, one can choose a suitable fender type and design from a wide range of available marine fenders in the market today: from super cone type, arch type, cylindrical shaped, to floating types like Yokohama fenders and foam fenders. Be sure to select a manufacturer that adheres to PIANC2002 and/or other standards to ensure great quality fender products.

GT Gross Tonnage Total volume of cargo + vessel
NT Net Tonnage Total volume of cargo on vessel
DPT Displacement Tonnage Total weight of the cargo-filled vessel when vessel is loaded to the draft line
DWT DeadWeight Tonnage Weight of cargo + people (including crew) + fuel + food on the vessel
LOW Light Weight Vessel weight
BW Ballast Weight Weight of the vessel when water is added in the ballast

Types of Berthing Approach:

Side Berthing:

Side Berthing

‘Dolphin’ Berthing:

dolphin berthing

End Berthing:

end berthing

Lock Entrances:

lock entrances

Ship-to-ship (STS) Approach:

Ship-to-ship Berthing Operation

This article only discusses berthing calculations for side berthing. If you have a Ship-to-ship (STS) operation or End Berthing, certain equations may be different. Contact our team for assistance.

Effective Berthing Energy formula for Side Berthing:

Vessel side berth fender selectionside-berthing

This is the most common berthing method for docks. The berthing energy is calculated with the equation:

EB = Berthing energy (kJ, N*m, or lbF*ft)

 EB = 0.5 × WD × VB × VB  × CM × CE × CC × C

*click to open/close

WD = Water displacement of the vessel (kg, tons, lbs)

WD = Water displacement of the vessel (kg, tons, lbs)This is the Total Displacement Tonnage(DPT) of the vessel.

VB = Berthing velocity of the vessel at the moment of impact (m/sec, ft/sec)

VB = Berthing velocity of the vessel at the moment of impact (m/sec, ft/sec). Berthing velocity is an important parameter in fender system design. It depends on the size of the vessel, loading condition, port structure, and the difficulty of the approach. The most appropriate method to determine berthing velocity is based on actual previous statistical data. If that is not possible, the most widely used reference would be the Brolsma table, adopted by BSI, PIANC and other standards. However, it is important to keep in mind that the best option is still to base on previous statistical information.

berthing-velocity-fender-design

CM = Virtual mass factor

 

CM =  Mass Coefficient/Virtual mass factor: During the sudden stop of movement as a vessel comes into contact with the berth, the mass of water moving with the vessel adds to the energy acting upon the vessel and fender. This situation is referred to as “Added Mass Coefficient” or “Mass Factor”. Weight of water moving that adds to that is called “ Additional Weight” in these berthing studies.

As the vessel is stopped by the fenders, the momentum of the water continues to push against the vessel and this actually increases its overall mass, so CM has to be calculated. There are 2 ways to calculate its mass coefficient.

The most commonly used “Vasco Costa (1964) method”:

virtual mass factor calculation

Formula B:

virtual mass factor 2 fender

C E = Eccentricity factor

  C E = Eccentricity factor. The reaction force will give a rotational movement at the moment of contact. This will dissipate an amount of the energy. There are 2 formulas to determine the eccentricity factor:

vessel berthing essentricity

You require these info:

  • Distance between center of mass (vessel’s) to the point of impact (R)
  • Velocity vector angle (v)
  • Radius of gyration (K)
  • Berthing angle(α)

NOTE: 

K: Radius of vessel rotation (usually 1/4 of the vessel’s length)

R: Distance of the line paralleled to wharf from the vessel’s Center of Gravity (CG) to the contact point. Common cases are 1/4 to 1/5 of vessel’s length.

CB: Block Coefficient, which is related to the hull shape.

WD: Water displacement of the berthing ship(kg, Tons, lbs)

sea water density symbol: Sea Water density(1.025 Tons/m3)

LBP: Length between perpendiculars. Please see sketch below for better explanation:

x: Distance from bow to point of impact

B: Beam(m, ft)

 

Formula (i): The more detailed calculation to find out C E :

Eccentricity formula

If the beam, length and draft information are not available, this table can be used to estimate:

Typical Block Coefficients(CB)
Type of Vessel  CB
BS 6349
 CB
PIANC 2002
Tankers 0.72~0.85 0.85
Bullk Carriers 0.72~0.85 0.72~0.85
Container Ships 0.65~0.75 0.60~0.80
General Cargo 0.60~0.75 0.72~0.85
RoRo Vessels 0.65~0.70 0.70~0.80
Ferries 0.50~0.65 0.55~0.65

Formula (ii): The more simple formula to find out C E :

eccentricity 2

This method can lead to a serious underestimation of Berthing Energy when the berthing angle (α) is greater than 10° and/or the point of impact is aft of quarter-point(x > LBP/4).

To verify your calculations, one can check the calculated C E values to ensure they generally fall within the following limits:

Quarter-Point Berthing x = L/4 Ce = 0.5
Third-Point Berthing x = L/3 Ce = 0.6 ~ 0.8
Mid-Vessel Berthing x = L/2 Ce = 1
CC = Berth configuration factor

 CC = Berth configuration factor. This is the part of berthing energy absorbed by the cushion effect of water between the approaching vessel and the quay wall. The smaller the draft (D) of the vessel is, or the larger the under keel clearance(KC), the more trapped water can escape under the vessel, and would give a higher CC value.  Also, if the berthing angle of the vessel is greater than 5°, we can consider CC = 1. Different dock types would have different variations.

Closed Dock case
A closed Dock would be a wharf, where you have a concrete wall going directly to the sea ground. In this case the quay wall will push back all the water that is being moved by the vessel. This creates a resistance factor that can be calculated as follows:

If KC ≤  D / 2, C≈ 0.8

If KC >  D / 2, C≈ 0.9

Open / Semi-Closed Dock case
A semi-closed dock is when water can flow underneath the dock, but the depth changes below the dock. Open dock is usually a dock with piles underneath and the water can flow freely underneath the dock. In such case we can assume the following value of 1.

C≈ 1

CS = Softness factor

  CS = Softness factor. This is the energy absorbed by the deformation of the vessel’s hull and fender. Usually, we can assume CS ≈ 0.9.

When selecting the size of fenders, it should be selected base on the consideration of kinetic energy of contact between two vessels or between vessel and berthing facilities may be absorbed by a single fender. The following tables are given for determining the energy absorption depends on approaching velocities for various ships.

Energy absorption for ship-to-Jetty (for reference only)

*click to open/close

Energy Absorption of Oil Tankers at ¼ point Berthing (kJ)

Table (i) Energy Absorption of Oil Tankers at ¼ point Berthing (kJ)

DWT Assumed

Weight(t)

Approaching velocity (m/s)
0.10 0.12 0.15 0.18 0.20 0.25 0.30 0.40
300 668 1.7 2.5 3.8 5.5 6.8 11.0 15.0 27.0
500 1,091 2.8 4.0 6.3 9.0 11.0 17.0 25.0 45.0
700 1,558 4.0 5.7 8.9 13.0 16.0 25.0 36.0 64.0
1,000 2,228 5.7 8.2 14.0 18.0 23.0 36.0 51.0 91.0
2,000 4,294 11.0 16.0 28.0 35.0 44.0 68.0 99.0 175
3,000 6,470 17.0 24.0 37.0 53.0 66.0 103 149 264
4,000 8,363 21.0 31.0 54.0 69.0 85.0 133 192 341
5,000 10,594 27.0 39.0 61.0 88.0 108 169 243 432
6,000 12,184 31.0 45.0 70.0 101 124 194 280 497
7,000 14,084 36.0 52.0 81.0 116 144 225 323 575
8,000 16,066 41.0 59.0 92.0 133 164 256 369 656
10,000 20,373 52.0 75.0 117 168 208 325 468 832
12,000 23,851 61.0 88.0 137 197 243 380 548 974
15,000 29,493 75.0 108 169 244 301 470 677 1200
17,000 33,056 84.0 121 190 273 337 527 759 1350
20,000 38,623 99.0 142 222 319 394 616 887 1580
25,000 45,946 117.0 169 264 380 469 733 1050 1880
30,000 56,093 143.0 206 322 464 572 894 1290 2290
35,000 63,084 161.0 232 362 521 644 1010 1450 2570
40,000 72,771 186.0 267 418 601 743 1160 1670 2970
45,000 77,986 199.0 286 448 645 796 1240 1790 3180
50,000 89,818 229.0 330 516 742 917 1430 2060 3670
60,000 104,300 266.0 383 599 862 1060 1660 2390 4260
65,000 114,637 292.0 421 658 948 1170 1830 2630 4680
70,000 122,108 312.0 449 701 1010 1250 1950 2800 4980
80,000 136,972 349.0 503 786 1130 1400 2180 3140 5590
85,000 143,359 366.0 527 823 1180 1460 2290 3290 5850
100,000 166,004 423.0 610 953 1370 1690 2650 3810 6780
120,000 200,083 510.0 735 1150 1650 2040 3190 4590 8170
150,000 251,896 643.0 925 1450 2080 2570 4020 5780 10280
200,000 327,735 836.0 1200 1880 2710 3340 5230 7520 13380
250,000 401,268 1020 1470 2300 3320 4090 6400 9210 16380
330,000 548,670 1400 2020 3150 4530 5600 8750 12600 22390
370,000 627,016 1600 2300 3600 5180 6400 10000 14400 25590
480,000 795,540 2030 2920 4570 6580 8120 12680 18260 32470
Energy Absorption of Ore Carriers at ¼ point Berthing (kJ)

Table (ii) Energy Absorption of Ore Carriers at ¼ point Berthing (kJ)

DWT Assumed

Weight(t)

Approaching velocity (m/s)
0.10 0.12 0.15 0.18 0.20 0.25 0.30 0.40
1,000 2,360 6.0 8.7 14.0 20.0 24.0 38.0 54.0 96.0
2,000  4,429 11.0 16.0 25.0 37.0 45.0 71.0 102 181
3,000 6,453 16.0 24.0 37.0 53.0 66.0 103 148 263
4,000 8,341 21.0 31.0 48.0 69.0 85.0 133 192 340
5,000 10,301 26.0 38.0 59.0 85.0 105 164 237 420
6,000 12,574 32.0 46.0 72.0 104 128 200 289 513
8,000 16,332 42.0 60.0 94.0 135 167 260 375 667
10,000 20,516 52.0 75.0 118 170 209 327 471 837
12,000 24,345 62.0 89.0 140 201 248 388 559 994
15,000 29,572 75.0 109 170 244 302 471 679 1210
20,000 38,068 97.0 140 219 315 388 607 874 1550
25,000 45,116 115 166 259 373 460 719 1040 1840
30,000 54,874 140 202 315 454 560 875 1260 2240
40,000 71,143 181 261 408 588 726 1130 1630 2900
50,000 86,432 220 318 496 714 882 1380 1980 3530
60,000 101,383 259 372 582 838 1030 1620 2330 4140
70,000 119,062 304 437 683 984 1210 1900 2730 4860
80,000 132,125 337 485 758 1090 1350 2110 3030 5390
90,000 149,528 381 549 858 1240 1530 2380 3430 6100
100,000 175,960 449 646 1010 1450 1800 2810 4040 7180
150,000 256,357 654 942 1470 2120 2620 4090 5890 10460
200,000 319,149 814 1170 1830 2640 3260 5090 7330 13030
270,000 426,459 1090 1570 2450 3520 4350 6800 9790 17410
Energy Absorption of Freighters at ¼ point Berthing (kJ)

Table (iii) Energy Absorption of Freighters at ¼ point Berthing (kJ)

DWT Assumed

Weight(t)

Approaching velocity (m/s)
0.10 0.12 0.15 0.18 0.20 0.25 0.30 0.40
700 1,585 4.0 5.8 9.1 13.0 16.0 25.0 36.0 65.0
1,000 2,237 5.7 8.2 13.0 18.0 23.0 36.0 51.0 91.0
2,000 4,357 11.0 16.0 25.0 36.0 44.0 69.0 100 178
3,000 6,606 17.0 24.0 38.0 55.0 67.0 105 152 270
4,000 8,712 22.0 32.0 50.0 72.0 89.0 139 200 356
5,000 10,795 28.0 40.0 62.0 89.0 110 172 248 441
6,000 13,515 34.0 50.0 78.0 112 138 215 310 552
7,000 15,557 40.0 55.0 89.0 129 159 248 357 635
8,000 17,703 45.0 65.0 102 146 181 282 406 723
9,000 19,625 50.0 72.0 113 162 200 313 451 801
10,000 21,630 55.0 79.0 124 179 221 345 497 883
12,000 26,052 66.0 96.0 150 215 266 415 598 1060
15,000 31,477 80.0 116 181 260 321 502 723 1280
17,000 36,784 94.0 135 211 304 375 586 845 1500
20,000 41,748 107 153 240 345 426 666 959 1700
30,000 60,483 154 222 347 500 617 964 1390 2470
40,000 79,393 203 292 456 656 810 1270 1820 3240
50,000 98,306 251 361 564 813 1000 1570 2260 4010
Energy Absorption of Passenger Ships at ¼ point Berthing (kJ)

Table (iv) Energy Absorption of Passenger Ships at ¼ point Berthing (kJ)

DWT Assumed

Weight(t)

Approaching velocity (m/s)
0.10 0.12 0.15 0.18 0.20 0.25 0.30 0.40
500 845 2.2 3.1 4.9 7.0 8.6 13.0 19.0 34.0
1,000 1,709 4.3 6.2 9.8 14.0 17.0 27.0 39.0 70.0
2,000 3,500 8.9 13.0 20.0 29.0 36.0 56.0 80.0 143
3,000 5,282 13.0 19.0 30.0 44.0 54.0 84.0 121 216
4,000 7,105 18.0 26.0 41.0 59.0 73.0 113 163 290
5,000 8,912 23.0 33.0 51.0 74.0 91.0 142 205 364
6,000 12,083 31.0 44.0 69.0 100 123 193 277 493
7,000 13,873 35.0 51.0 80.0 115 142 221 319 566
8,000 15,346 39.0 56.0 88.0 127 157 245 352 626
9,000 16,986 43.0 62.0 97.0 140 173 271 390 693
10,000 18,661 48.0 69.0 107 154 190 298 428 762
15,000 26,283 67.0 97.0 151 217 268 419 603 1070
20,000 33,423 85.0 123 192 276 341 533 767 1360
30,000 47,952 122 176 275 396 489 765 1100 1960
50,000 71,744 183 264 412 593 732 1140 1650 2930
80,000 111,956 286 411 643 925 1140 1790 2570 4570
Energy Absorption of Barges or Lighters at ¼ point Berthing (kJ)

Table (v) Energy Absorption of Barges or Lighters at ¼ point Berthing (kJ)

G/T Assuming Weight ( t ) Approaching velocity ( m/s )
0.20 0.25 0.30 0.35 0.40 0.50 0.60
50 85 0.9 1.4 2.0 2.7 3.5 5.4 7.8
100 161 1.6 2.6 3.7 5.0 6.6 11.0 15.0
150 241 2.5 3.8 5.5 7.5 9.8 15.0 22.0
200 319 3.3 5.1 7.3 10.0 13/0 20.0 29.0
300 496 5.1 7.9 11.0 15.0 20.0 32.0 46.0
Energy Absorption of Container Ships at ¼ point Berthing (kJ)

Table (vi) Energy Absorption of Container Ships at ¼ point Berthing (kJ)

G/T DWT Assumed Weight (t) Approaching velocity ( m/s )
0.10 0.15 0.20 0.25 0.30 0.40
8,000 12,000 26,752 68 154 273 427 614 1090
9,000 14,000 33,567 86 193 343 535 771 1370
16,626 16,004 38,172 97 219 390 609 876 1560
21,057 20,400 48,995 125 281 500 781 1120 2000
23,600 23,650 55,560 142 319 567 886 1280 2270
30,992 27,203 64,264 164 369 656 1020 1480 2620
38,826 33,287 79,599 203 457 812 1270 1830 3250
41,127 27,752 67,121 171 385 685 1070 1540 2740
51,500 28,900 68,664 175 394 701 1090 1590 2800
57,000 49,700 105,199 268 604 1070 1680 2420 4290
Energy Absorption of Fishing Vessels at ¼ point Berthing (kJ)

Table (vii) Energy Absorption of Fishing Vessels at ¼ point Berthing (kJ)

Type G/T Assumed Weight ( t ) Approaching velocity ( m/s )
0.20 0.25 0.30 0.35 0.40 0.50 0.60
Whale

factory

ship

10,000

17,000

20,000

34,058

53,494

66,217

348

546

676

543

853

1060

782

1230

1520

1060

1670

2070

1390

2180

2700

2170

3410

4220

3130

4910

6080

Whale ship 400

800

1,000

1,797

3,263

3,950

18.0

33.0

40.0

29.0

52.0

63.0

41.0

75.0

91.0

56.0

102

123

73.0

133

161

115

208

252

165

300

363

Trawler

Vessel

400

800

1,000

2,000

3,000

2,297

3,693

4,458

7,173

9,863

23.0

38.0

45.0

73.0

101

37.0

59.0

71.0

114

157

53.0

85.0

102

165

226

72.0

115

139

224

308

94.0

151

182

293

403

146

236

284

457

629

211

339

409

659

906

Skipjack

vessel

20

50

100

200

126

202

390

779

1.3

2.1

4.0

7.9

2.0

3.2

6.2

12.0

2.9

4.6

9.0

18.0

3.9

6.3

12.0

24.0

5.1

8.2

16.0

32.0

8.0

12.9

25.0

50.0

12.0

19.0

36.0

72.0

Mackerel

vessel

20

50

100

112

266

525

1.1

2.7

5.4

1.8

4.2

8.4

2.6

6.1

12.0

3.5

8.3

16.0

4.6

11.0

21.0

7.1

17.0

33.0

10.0

24.0

48.0

Tuna

long-liner

150

200

400

590

780

1,681

6.0

8.0

17.0

9.4

12.0

27.0

14.0

18.0

39.0

18.0

24.0

53.0

24.0

32.0

69.0

38.0

50.0

107

54.0

72.0

154

Round

Haul netter

20

50

100

75

191

377

0.8

1.9

3.8

1.1

3.0

6.0

1.7

4.4

8.7

2.3

6.0

12.0

3.1

7.8

15.0

4.8

12.0

24.0

6.9

18.0

35.0

Towing

net vessel

20

50

100

300

500

99

204

361

1,138

1,838

1.0

2.1

3.7

12.0

19.0

1.6

3.3

5.8

18.0

29.0

2.3

4.7

8.3

26.0

42.0

3.1

6.4

11.0

36.0

57.0

4.0

8.3

15.0

46.0

75.0

6.3

13.0

23.0

73.0

117

9.1

19.0

33.0

105

169

General

fishing

vessel

20

50

100

150

77

195

350

500

0.8

2.0

3.6

5.1

1.2

3.1

5.6

8.0

1.8

4.5

8.0

11.0

2.4

6.1

11.0

16.0

3.1

8.0

14.0

20.0

4.9

12.0

22.0

32.0

7.1

18.0

32.0

46.0

Energy Absorption of Ferry Boats at ¼ point Berthing (kJ)

Table (viii) Energy Absorption of Ferry Boats at ¼ point Berthing (KJ)

G/T Assumed Weight (t) Approaching velocity ( m/s )
0.20 0.25 0.30 0.35 0.40 0.50 0.60
50 124 1.3 2.0 2.8 3.8 5.1 7.9 11.0
100 246 2.5 3.9 5.6 7.7 10.0 16.0 23.0
200 430 4.4 6.9 9.9 13.0 18.0 27.0 39.0
300 664 6.8 11.0 15.0 21.0 27.0 42.0 61.0
500 1,012 10.0 16.0 23.0 32.0 41.0 65.0 93.0
1,000 1,796 18.0 29.0 41.0 56.0 73.0 115 165

After having the effective berthing energy value, one can then choose the suitable type of marine fender design / system. Performance has to be compared in order to design the most suitable system. For example, deflection curve, energy absorption and reaction of a cylindrical fender is different from an arch-shaped fender. One has to compare alternatives and then determine which one is more suitable for use. This is when previous records of fender systems deployed play a big role in advising the suitability for the particular marine condition.

Energy Absorption:

The obvious factor in designing a fender system. This value has to be higher than the effective impacting energy of ships.

Reaction Force:

This value has to be less than the vessel’s allowable reaction force to prevent damage to the hull surface (or in extreme cases, the structure as a whole).

Environmental Condition:

It is vital to determine how harsh the working conditions for the fenders will be. One will have to choose accordingly its durability to handle strong waves, winds, or extreme weather. If the working condition is very demanding, it is possible you will have to replace the fenders quite often.

Berthing Angle:

A fender that can accept a situation’s angular compression has to be considered. An angular compression does not result in a simplistic linear energy absorption curve so this has to be a main priority when choosing a rubber fender design.

Fender (or Panel) Surface Pressure

Surface pressure value of fender has to be less than the vessel’s allowable hull surface pressure. For certain fenders like super cell type and cone type, they most commonly come with frontal frames/panels that distributes the pressure. So to decrease surface pressure value, one can increase the surface area of the panel.

Trustworthy Supplier

Choose a quality rubber fender manufacturer. Some people always assume that prices and quality can not come together but it is possible in today’s manufacturing innovation and high tech automation processes. Manufacturers are spending less time doing low importance repetitive work and focusing on Quality Control (QC) processes assisted by great process flow.

port-fender-distance

Fender Arrangement and Spacing In Between

After choosing what type and size of fenders to use, the next step is determining the number of fenders. To do that, one has to take into consideration fender spacing. The spacing between fenders play a very important role in determining a fender system’s success. Should one opt to save cost and have too great a spacing between fenders, accidents might happen where vessel berthing might hit the dock structure. British Standards recommend that for a continuous quay, the installation pitch is recommended to be less than 15% of the vessel.

The maximum spacing between fenders (S) can be calculated with this equation:

Maximum Spacing between Fenders, Space

Note:

RB = Bow Radius of Board Side of Vessel (m, ft).

If radius info is not available, one can use this estimation to find out the info:

Radius Calculation

PU = Uncompressed Height of Fender incl. Panel (m, ft)

C = Fender Height in Rated Compression.

deflection = Fender Deflection (m, ft)

For arrangement consideration especially distance between fenders, it is important to keep in mind that one should not only have the largest vessel type in mind. As smaller vessel might face problems berthing if one only design for large vessels.

This shows an improper design as smaller vessels berthing at the dock would crash into the wall:

fender design failure 1

This might be a possible solution for this situation:

fender design solution

Of course, aside from fender spacing, all aspects from angular compression energy absorption to hull pressure per unit needs to be considered as well. If a particular type does not satisfy requirement, one should consider other options.

Choosing a Suitable Frontal Panel

To choose a suitable panel, one has to consider hull pressures allowed for the berthing vessels. The following table shows a rough guide of allowable hull pressures of certain popular type of vessels. (just for reference):

Allowable Hull Pressures

Vessel Type Hull Pressure KN/m2
Tankers 150~250
ULCC & VLCC(Coastal Tankers) 250~350
Product & Chemical Tankers 300~400
Bulk Carriers 150~250
Post-Panamax Container Ships 200~300
Panamax Container Ships 300~400
Sub-Panamax Container Ships 400~500
General Cargo 300~600
Gas Carriers 100~200

Calculation:

vessel hull pressure calculation
PHull Pressure(N/m2, psi)
ΣRCombined Reaction Forces of all rubber fenders
A1: Valid Panel Width excluding lead-in chamfers(m)
B1: Valid Panel Height excluding lead-in chamfers(m)
PP: Permissible hull pressure(N/m2, psi)

Another option: WITHOUT frontal frames.

Rubber fenders like arch fenders and cylindrical fenders do not come with frontal frames. The fender body itself comes into contact with the vessel’s hull during berthing. One has to carefully consider the hull pressure exerted.

Selecting the Chains

cone fender installation

A common fender system with frontal frame usually involve a Weight Chain, Tension Chain and Shear Chain.

Chain Function
Weight Chain Normally installed at a static angle of 15 – 25° to the vertical, its main function is to sustain the weight of the entire frame panel structure
Tension Chain Protect the fender against damage when compressed
Shear Chain Fixed at 20 – 30° to the horizontal, shear chain exists to avoid damage while the fender is in shear deformation

Some installation do not involve shear chain, but a fender system would definitely be more resistant to shear damage with them.

chain selection equationchain selection

h1Static offset between brackets(m, ft)
Ф2:
 Dynamic Angle of Chain(°)
h2
Dynamic offset between brackets at F(m, ft)
D: 
Fender compression(m, ft)
R
Reaction Force of rubber units behind the frontal panel(N, Lbs)
WWeight of the panel face(N, Lbs)
FLSafe working Load of chain(N, Lbs)
L: Bearing length of chain(m, ft)
n: number of chains acting together
μ: Friction coefficient of face pad. Usually equals 0.15 for UHMW-PE facings.
FM: Minimum Breaking Load(N, Lbs)
FS: Safety Factor(2~3 times)

Tips on choosing suitable chains:

  • Chain sizes should be as exact as possible. An overly tight chain or an overly loose chain would fail the system.
  • Safety factor has to be considered. At least 2 to 3 times of the work load.
  • Open link type is more preferable.

Installation tips:

  • One must consider installation during the early design process and not after choosing the fenders and finalising the purchase as the maintenance, wear allowances and protective nets/coatings will affect their useful life.
  • Chains should not be installed twisted. They might break due to a reduction in load capacity.

A small tip after preliminary choosing the type of fenders to use, make sure you do not make these 5 top mistakes that causes structural failures for marine fenders.

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