Fender in port is a device used to protect a vessel from collision with a dock, pier, or any other vessel near the shore. Fenders act as buffers or absorbers, absorbing kinetic energy through elastic action. This mitigates the impact of mutual contact. Harbor fenders are therefore effective in preventing structural damage to vessels.
Why Do We Need Fender in Port?
All vessels are required to berth at designated locations. During this operation, the vessel must position itself in a specific location to fulfill its purpose. At the same time, the crew needs to take into account the available space and other elements of the pier, harbor, dock, piers, shoreline, etc. When a vessel is moored, it can be secured by mooring buoys.
As a result, there is a considerable risk of contact or collision with the harbor or other structures, even if the vessel is traveling at extremely slow speeds. The risk of contact remains high when the vessel is at anchor at a mooring. Although a ship’s speed is zero after docking or mooring. However, the nature of the waters is very dynamic.
Continuous motion is caused by currents, tides, and waves. As a result, even vessels that are not floating may occasionally come into contact with shore structures. In addition, different vessels serve different purposes at breakwaters, piers, docks, harbors, or ashore. As a result, there is a high likelihood of direct contact between individual vessels.
On the other hand, the risk of collision with another vessel increases when a vessel approaches a port or harbor with heavy traffic. In addition, two vessels may be docked together for various purposes such as refueling or cargo transshipment, which is known as ship-to-ship transshipment (STS).
Thus, harbor fenders were born out of this need. You can see these rubber fenders in various ports. Common fenders in port include arch rubber fenders. For the same purpose, there are many different types of marine fenders that can be used for small speedboats to large cargo ships. These rubber marine fenders protect the hull structure from localized collisions and impacts.
Factors to Consider When Selecting a Fender
A fender designed for one use may not be effective at all for another. It therefore depends on the type and purpose of the vessel. The selection of fenders for a particular location and operation therefore depends on a variety of circumstances.
Type of Vessel
This is the most critical consideration. Fender solutions designed for fishermen’s ports are totally ineffective for huge cargo ships in the harbor. In addition, the type, size, and design of the vessel are important. For example, arch fenders are suitable for small to medium-sized vessels.
Similarly, bulk carriers and general cargo vessels must be moored close to the quay or trestle with limited clearance. This ensures efficient transfer of cargo through maximum crane reach. Similarly, passenger ships need this to ensure safe and easy embarkation and disembarkation of passengers.
As a result, large flat fenders of the right size and shape, which are robust and require minimal clearance, are often used.
In addition, modern fender systems include advanced types such as parallel motion, sliding, and retractable extrusion. They are capable of absorbing large ship momentum for long periods of time, while also adjusting accordingly to external forces. This minimizes the gap between the ship and the port terminal. The berthing energy is directly proportional to the ship type.
Structure and Environment
Coastal structures and the environment are important. The conditions in which a breakwater, pier, or jetty is located determine the risk of collision and the forces involved in the contact. Examples include tide levels, wave factors, currents, etc.
Similarly, the type and configuration of the structure are also considered. For example, open pile breakwaters, which are common in deep water operations, are load sensitive and have limited fender area. Large, efficient fendering devices are therefore required. These devices are not only capable of withstanding the high loads of large vessels but can also operate under variable external conditions such as high tide or large wave loads.
Mooring Configurations and Methods
Vessels can be moored alongside in a variety of ways depending on their needs and design. Side berthing is the most common way, followed by end berthing (bow or stern). In addition, there are rare methods such as dolphin berthing or lock berthing. Thus, when a vessel must berth from the bow or stern, the berthing arrangement on the vessel and structure is different from the side berthing technique.
This element is again directly related to the first point (type of vessel). For example, if a ship has a spherical bow and must berth from the front. Then its fenders are different from those of a ship without a spherical bow. Other key aspects include approach speed, approach angle, etc.
Fender Type, Design and Arrangement
In the area where interaction is most likely to occur. Harbor fenders are usually arranged in a line at more or less regular intervals. These fenders are scattered at the farthest edges of the harbor, wharf, or trestle. There, they may come into contact with the ship’s hull. In addition, rubber fenders are also placed on the side hulls of boats and ships near the waterline and deck edges.
Thus, for harbors, fenders may be placed as needed. For all practical purposes, however, the use of fenders is optional for large seagoing vessels underway. This is because there is no risk of low-scale collisions in deep waters and because ship fenders affect weight, stability, and speed.
Types of Fenders
For fenders in port, they vary greatly in size, shape, type, and design. Some common types of fenders by shape include the following:
- Cylindrical fenders
- Spherical fenders
- Square fenders
- Corner fenders
- Round Fenders
- Conical fenders
- Circular Fenders
- Arch Fender
- D-shaped fenders
Depending on their mobility, there are several types:
- Fixed fenders
- Floating fenders
As the name suggests, fixed fenders are fixed to a structure such as a ship or harbor platform. A floating fender is suspended in the water and is allowed to float. It acts as a buffer between two objects such as a vessel or a fixed structure.
In addition, fenders can be broadly classified into the following categories based on their construction and design:
- Flatbed fenders
- Pneumatic fenders
- Foam fenders
Application Scenarios
Flat plate fenders are only used for land structures such as breakwaters, bridge piers, and harbors. They consist mainly of rubber and have a high stiffness index. They do not compress significantly and are therefore suitable for low-momentum collisions. They are generally circular, ring, square, or D-shaped.
Since they are generally land-based, they are primarily fixed fenders. Pneumatic fenders, on the other hand, are most commonly used between ships. However, they are also used on land when larger ships are involved.
Pneumatic fenders are larger and filled with pressurized air. As a result, they can absorb a lot of energy without deflecting too much. Pneumatic fenders offer greater flexibility and are ideally suited for mooring between two floating vessels with a large degree of freedom. In addition, it is also suitable for mooring large vessels at very high speeds. Pneumatic fenders are mainly cylindrical or spherical in shape.
Due to their pneumatic properties, they are mostly categorized as floating fenders. Foam fenders, like pneumatic fenders, have the ability to float due to their construction. They have an internal foam core and an external shell made of a synthetic polymer or elastomer. Another advantage of the foam polymer is that it does not deflate when punctured.
Mechanized fenders that adjust and retract according to loading pressure are also common today. Some common types of fenders include legged, extruded, sliding, and parallel motion.
Design Factors
- Berthing Energy: This is the most important parameter in fender design. Berthing energy is the kinetic energy of an impact load as it moves from a vessel to a berth or between two successive vessels.
- Fender Spacing: the distance between two neighboring fenders. This depends on the type of vessel, the environment, and the mooring method.
- Fender Contact: the force shared by each fender. This is related to the mooring configuration and vessel type. As mentioned earlier, when the vessel is moored sideways, the forces on the fenders are more or less uniform. This is because the entire loading cycle is highly dynamic.
Materials
In addition, the type of fender determines the material used. For example, in foam fenders, the inner core is foam and the outer core is elastomer. Flatbed fenders are usually reinforced with polyethylene, rubber, and sometimes steel.
Inflatable fenders use regular rubber (similar to tires) and monomers. In addition, polyvinyl chloride is a widely used material. Mechanical fenders are mainly made of steel and are filled with rubber at the point of contact. Thus, the choice of material is based on the strength and functional requirements of the fender.
Summary
In conclusion, fenders in ports are important marine equipment for the protection of ships and harbor facilities. By absorbing the kinetic energy of a berthing ship, fenders prevent damage to the hull and docking structure. Therefore, harbor fenders can ensure safe and efficient marine operations.
In addition, the design and selection of fenders is critical. This is because they must be tailored to suit a variety of vessel sizes, types, and environmental conditions. It is important to understand the different types of fenders and their specific applications. This is because it contributes to the safety and longevity of port facilities.
FAQ
What is the primary function of marine fenders?
Marine fenders are designed to absorb the energy of ship impacts. It protects ships and harbor infrastructure from damage during berthing operations.
How do different types of marine fenders vary in their application?
Different types of marine fenders, such as pneumatic fenders, arch fenders, and cellular fenders. They are suitable for all sizes and types of vessels, as well as for different mooring conditions and environmental factors.
What factors should be considered when selecting a fendering system for a port?
When selecting a fendering system, factors such as vessel type and size, berthing energy, environmental conditions, and mooring configurations should be taken into account to ensure optimal performance and protection.
How do marine fenders contribute to the longevity of port infrastructure?
By absorbing the impact of ships during berthing, marine fenders help reduce wear and tear on port infrastructure. This extends their service life and minimizes maintenance costs.
How often should marine fenders be inspected and maintained?
Regular inspections and maintenance are crucial to ensure the optimal performance of marine fenders. The frequency of these checks depends on factors such as usage, environmental conditions, and manufacturer recommendations.
Can marine fenders be customized to meet specific port requirements?
Yes, marine fenders can be customized to meet the unique needs of a particular port. Factors such as vessel traffic, berthing conditions and environmental factors also need to be considered.
