The role of ship anchor chain
The main function of the ship anchor chain is to fix and stabilize the ship. From the following aspects.
1. For the anchor chain to work, the most basic condition is to hook things on the seabed. If the anchor chain is not long enough, the anchor will not work. If the seabed is flat, or the thing the anchor is hooked on is not fixed, or the hook is not too strong, if it is calm and the waves are still okay, once the waves are too big, the anchor will not be able to hook things, and the anchor will lose its function. This is called "anchor walking". It is very dangerous for the ship to move anchor during the anchoring period, because the main engine usually stops when the ship is anchored. If the ship is driven immediately, it takes time, and it is very dangerous for a ship without power to drift around. dangerous. Therefore, the concept of anchorages came into being. Anchorages, in implication, are rougher under the sea, and in addition, they must be sheltered from the wind.
2. The weight of the anchor chain is negligible for the ship, and that little friction will not play a big role. Generally speaking, when the ship is anchored, the anchor chain is straight, which is basically negligible friction. If you are by the sea, you will find many small fishing boats whose anchor chains are thick ropes.
3. Looking from the top of the ship, the anchor chain is straight, but there is a section under the water that is close to the seabed (in fact, it is close to the seabed). The anchor provides the holding power, which is then transmitted to the ship through the anchor chain to resist the influence of the external load of the sea currents and wind waves on the positioning. The reason why there is a section close to the seabed is to consider the influence of the force. Think about it, an anchor, the anchor chain is straight and easy to move the anchor. And there is a section close to the bottom of the sea, which can provide a margin within a certain range.
Structural characteristics
The anchor chain is made up of many chain links, and the size is expressed by the chain diameter (mm). According to whether there is a supporting gear in the middle of the chain link, it is divided into a gear anchor key and a gearless anchor chain. The anchor chain can be made by forging, casting and welding. The marine anchor chain is composed of a number of "shackles", each of which is 25.0-27.5 meters long, and the nodes are connected by chain links or shackles. After the anchor is twisted, the chain is stored in the chain locker at the bow of the ship. The specifications of the anchor chain are calculated and confirmed in accordance with the ship construction standards.