The relationship between fender installation and water level

Generally, the position of fender installation should be suitable for safe berthing of ships at various water levels, and the fender should be set between the designed high water level and the designed low water level. If the tidal range of the port is greater than 4 meters, certain measures should be taken. For ships above 50,000-ton class, due to the large hull and fender size, it has good adaptability to different water levels. On the contrary, the adaptability to 10,000 – 20,000-ton class ships will be worse.

The fender of gravity wharf is set on the breast wall, and the bottom elevation of breast wall is mostly at the construction water level. The high-piled wharf is specially equipped with berthing components, but the extended length is limited. Because of this kind of structural reasons, the elevation of fender is often biased towards the designed high water level, which is unfavorable for the combination of the designed low water level and the full load of ships.

For example, for a 10,000-ton class ship, the shape depth is more than 11m, the draft is nearly 9m when fully loaded, and the hull height that can be propped up above the water surface is very small. If the setting elevation of fender is too far away from the designed low water level, it will affect the safe berthing, and smaller ships may drill under the fender, which will form upward collision force against the fender and easily damage the fender.A fender with a face plate sometimes extends the face plate downward, which is why it is made into a special-shaped face plate. The smaller the ship type, the more difficult it is to adapt to berthing at different water levels. It is especially difficult for working ships of thousand-ton class or thousands of ton class.For the design of high water level, attention should be paid to the inclination of light-duty ships in berthing. When the ship is unloaded, the draft is scattered, and the shallow draft of medium-sized ships is only 2 meters. When designing high water level, if the elevation of fender top is too low, the hull will incline to the shore side, which is easy to cause accidents. Therefore, from the point of view of setting fender, it is necessary to find out the draft of the ship when it is unloaded and reasonably determine the elevation of fender.

The water level difference in some rivers and ports is very large, reaching about 10 meters. Therefore, floating berthing facilities are used in river port docks or ship locks. Floating berthing facilities are generally complicated in structure and high in cost, so most small inland river wharves adopt vertical continuous fender arrangement or layered fender arrangement. There are also fender layers in the harbor. When the water level difference is not too large, the interval layers are arranged in a state of one high and one low.

In a word, setting fender should consider various combinations of different tide levels and different cargo ships, so that they can berth safely under any circumstances.