D-Type Rubber Fenders
To reduce the impact force when a ship comes alongside a berth, protective fendering must be installed along the front of the wharf to prevent damage to both the ship and the structure from direct collision. Ports in China began adopting rubber fenders around 1970. The rubber fenders used around the world today fall into five types: compression, pneumatic (inflatable), shear, rotary and hydraulic, with the first two being the most widely used. Most rubber fenders used in Chinese ports are domestically made compression fenders, including cylindrical, V-type (arch), roller, floating, foam-filled and W-type rubber fenders.
Across many different wharf structures, ports have installed a wide range of rubber fenders, including drum, pneumatic, D-type, W-type, cylindrical and floating fenders. The choice of fender depends on the type of vessel, the structure of the wharf, and conditions such as tides, wind and waves. Rubber fenders offer high energy absorption, low reaction force, abrasion resistance, resistance to marine organisms, simple installation and easy maintenance, and domestically made fenders have reached a high standard.
Development of the D-type fender
The D-type rubber fender was developed from earlier traditional fender designs. Traditional fenders were fixed only along the middle, which made them prone to coming loose in service. The super D-type fender has a full-length embedded steel plate, larger anchor bolts and two rows of anchors, which considerably increases the anchoring force compared with the original design. Experience in service shows that the anchoring force meets design requirements.
Applications
Besides being used as the main fender on small wharves, D-type rubber fenders also serve as secondary protection (alongside other fenders) on the upper front face of a wharf. They are usually installed in a continuous line to stop ships striking the wharf when they do not berth normally.
Features
- Because of their narrow base, which needs only the mounting bolts, D-type fenders suit open-frame (piled) wharves and the upper part of quay walls.
- Easy to install and easy to replace.
- High energy absorption relative to the volume of rubber used, although the reaction force is comparatively high.