First of all, a brief introduction.
1. Dock refers to a dock-style building built for ships. After irrigation, ships can enter and exit, and after drainage, it can be built on a dry bottom. Dock can be divided into dry dock, water injection dock and floating dock. Dry dock is widely used, generally called dry dock. The dock evolved from the original ship pit.
2. On the tidal coast, people use the fluctuation of water level to lift the ship, that is, when the tide rises, they lead the ship into a "boat pit" surrounded by earth dikes on three sides, and when the tide falls, they position the ship on the preset pier, and then use cofferdam to close the gap and carry out repair work. When the ship comes out of the pit, the cofferdam is removed, and the high tide comes out of the pit.
3. Later, the earth embankment was gradually changed into dock wall and dock door, and the fluctuation of water level in the dock was controlled by water pump, which gradually evolved into dry dock. It is arranged in the shipyard and is mainly used for ship repair. Dock is a working platform where shipyards repair and build ships.
Second, history.
1. Dock was invented by Zhang Ping of Song Dynasty in China. According to historical records, Zhang Ping was born in Yangshan, Linqu in 925. He served as an official in charge of the Northern Song Dynasty, such as Shi Mu, Sacrifice Officer, Du Mu, Wu He Shipyard and Assistant Ambassador of Chongyi, such as Beijing Ambassador, Hakka Ambassador and Yantie Ambassador. He died in 987 and returned to his original place for a royal burial. "On the west side of the village, there are graves, with stone men and sheep in front of them.
2. In 977 AD, Zhang Ping was appointed as the sacrificial officer and supervisor of Yangping Woodwork and Shipyard, and lived in Yangping Town, east of Baoji City, Shaanxi Province. At that time, shipbuilding by the Weihe River was easy to be washed away by water, so it was necessary to send a boat and three households to guard it, recruiting thousands of migrant workers a year and wasting people and money.
Zhang Pingsui ordered the migrant workers to dig a big pit on the shore and build a boat in it. After the ship was built, they dug a hole and led the water into the pit. The boat floated up and sailed into the river. This pit is called "dock".
Third, dry dock.
1. The dry dock has three sides of land and one side of water, and its basic components are dock mouth, dock room and dock head. Dock is used for ships to enter and exit, and there are water retaining doors. The drainage and irrigation equipment of the dock is often built in the piers on both sides of the dock. The dock room is used for placing ships, and the bottom plate of the dock room is provided with keel piers and side piers for supporting the ships.
2. The docking head is the end opposite to the docking port, and its plane shape can be rectangular, semi-circular or diamond. The space of the dock head is a part of the dock room, where the propeller and tail shaft are disassembled. The dry dock is equipped with various power pipelines and auxiliary equipment such as lifting, derusting, painting and towing.
3. When the ship enters the dry dock for repair, firstly, water is injected into the dock from the drainage and irrigation facilities. When the water level inside and outside the dock is even, the dock door is opened, and the boat is slowly pulled into the dock by the traction equipment, and then the water in the dock is drained, so that the boat is located on the keel pier. When the repaired or built ship leaves the dock, firstly, fill the dock with water until the water level inside and outside the dock door is even, then open the dock door and guide the ship out of the dock.