The relationship between rubber fenders and mooring stability

In order to reduce the impact force of ships when berthing at the dock and prevent direct collision with the dock, which may cause damage to the ships and the dock, anti-collision equipment needs to be installed at the front of the dock. Rubber fenders were gradually adopted in various ports in China around 1970. Currently, rubber fenders used in various countries around the world can be divided into five types: compression, inflation, shear, rotation, and water pressure. The first two types are the most widely used. At present, most of the rubber fenders used by ports in China are domestic compression fenders, including cylinder, D, V, drum, floating and foam rubber fenders.
With the different types of dock structures, a total of 3771 rubber fenders are installed in Qin Port, including 24 drum type, 59 inflatable cap type, 2948 D-type, 460-10 V-type, 274 barrel type, and floating type. The choice of fender structure type depends on the ship type, dock structure type, and conditions such as tide, wind, and waves. Rubber fenders have advantages such as high energy absorption, low reaction force, wear resistance, insect resistance, simple installation, and convenient maintenance. Domestic and foreign fenders have reached the level of rubber, and the total annual investment in fenders in various ports in China can reach about 40 million yuan.
The spacing and elevation of rubber fenders are important to ensure that the ship does not directly touch the dock wall at the most unfavorable berthing angle allowed by the regulations. It should also ensure that the ship can safely berth at different tide levels and draft levels, and has strong adaptability to the berthing of ships of different tonnage. When selecting and deciding on the layout plan of the first, second, and third phase fenders for coal terminals, it is necessary to meet the berthing stability conditions for safe operations of different types of tonnage ships, which actually reflects the requirements of the terminal for the degree of wave protection. Fenders are energy absorbing devices for ship berthing stability, and the magnitude of the reaction force determines the three-dimensional spatial motion of the ship. The semi open Qingang coal terminal without cover, due to the effects of wind, waves, and currents, as well as the difference in dock orientation and the influence of wavelet high and long period waves on the harbor, can generate a large amount of ship collision energy with the berthing pier, This requires the newly adopted fenders to have good energy absorption characteristics. The cumulative frequency of allowable wave height in front of the dock is generally 4%. In foreign countries, 3% of the effective wave height is used. Due to the complex factors affecting the allowable wave height in front of the dock, the impact energy of longitudinal, transverse, and oblique waves on the dock and the induced ship motion parameters must be calculated.