The length of marine anchor chain is measured in "knots". China stipulates that the standard length of each anchor chain is 27.5m. The British system countries usually take 15 tons as a knot, which is limited to 27.5m when converted into meters. Some take 25m and 20m as a section.
A complete marine anchor chain is composed of anchor end link, middle link and end link. In addition to the chain links with swivels, the number of chain links of each anchor chain shall be odd to ensure that when connecting the chain links or connecting shackles pass through the windlass sprocket, they can lie flat in the socket of the sprocket and pass smoothly.
The length of a single section of anchor chain is derived from the English unit 'fathom', or 'tuo', which is a unique length unit used at sea. One section of anchor chain is about 1.8288 meters, which is about the length of a person's (of course, white Europeans) arms spread out. One section of anchor chain takes 15 sections, that is, more than 27.43 meters. When it is converted to the metric system, the mantissa is erased and 27.5 meters is taken directly. So it has been followed by convention.
Generally, for outfitting, the length of anchor chain L is selected according to the outfitting number N. One anchor chain is 27.5M long. When L selected according to the outfitting number is an even multiple of 27.5M, the left and right anchor chains are the same length. When it is an odd multiple, the starboard side is 27.5 longer than the port side. Personally, I think it may be related to anchoring at the port. Generally, it seems that port port docks and right anchor chain is thrown for positioning. It is possible to measure water depth on starboard, so the anchor chain should be one long!
Generally, the anchor chain of a ship is 27.5 meters long, and each anchor is equipped with 10 to 11 anchor chains. It is only about 300 when all the anchor chains are sent down. Therefore, the anchoring is generally about 30 meters deep in shallow water, and the anchor chain will work only if there is friction force under the anchor chain, while the anchoring location is generally in the special anchorage planned by the port authority!