It should be noted that the length of anchor chain should not be calculated in meters, but in the most commonly used nodes in navigation. The length of each section of marine anchor chain is about 27.5 meters. It is necessary to explain how this unit came into being.
The pitch length of anchor chain is different from the speed unit pitch used in navigation. It is actually derived from English units, fathoms. The length of one fathom is about 1.8288 meters. Because the British Empire was strong in navigation, it later became an international standard. Later, it was uniformly stipulated that the length of the anchor chain was 27.5 meters. In actual use, each section of the anchor chain is composed of a shackle, and the sections are connected by detachable links. Generally, the chain link will be sprayed white, so that the crew can know how many anchor chains have been launched.
The last section of the chain is usually sprayed red to warn the crew that they have reached the end of the chain. Generally, the anchor chain is fixed on the chain reel. If the ship has not finished decelerating before it is released, the anchor chain is likely to break and fly out of the ship. To prevent this, the last but one section of the anchor chain is usually sprayed yellow, similar to the use of traffic lights.
According to international practice, each anchor chain of a large commercial ship usually has only 12 to 13 knots, and the length is between 330m and 357.5m. However, this is only a vague standard value. Specific to a ship, it needs to be determined according to the outfitting number of the ship. The calculation method of outfitting number is very complex, so we won't repeat it here. We just need to understand that if the outfitting number of a ship is larger, it means that the ship is more affected by wind and waves at sea, so it needs to be equipped with heavier anchors, thicker anchor chains and ropes. Generally speaking, the outfitting number of warships is higher than that of ordinary freighters, but it is not suitable to lengthen the anchor chain after reaching 13 knots. Because it will prolong the anchor receiving time, the anchor chain needs to be thickened, or even more than one anchor chain to ensure stability.
