Anchors are still used after thousands of years. They allow ships to remain stable in places where there is nothing to moore against. However, in these instances when anchors are used, they are submerged in salt water, which is incredibly corrosive. How are they protected against the rust? Are there any tricks or secrets that sailors use?
Interestingly, anchors are quite immune to rust. They are painted with special paint and it doesn’t really matter if some rust starts showing up. However, the anchor chain is a different story. It is the component which is holding the weight of the ship against the waves and wind. It is seriously tortured when anchor is lowered or lifted and it rubs against other metal components of the anchoring mechanism. Rust is the cancer of steel so how are anchors and anchor chains protected from rust? Well, they aren’t.
Anchor chains are very thick – it would take decades for rust to weaken their structure to a point where it would become a problem. They are designed to hold the weight of the ship against the waves and wind, so some rust really doesn’t matter too much. And remember that rubbing against other metal components? Well, in this case it actually helps some rust to flake off and fall down to the ocean. This means that rust on anchors and anchor chains is mostly a cosmetic problem, which means that it is not a problem at all. But some maintenance is still needed.
First of all, chains are painted with a thick layer of marine paint. It eventually wears through, but for some time it offers a substantial amount of protection. Then every time when the anchor is raised sailors are spraying water on the chain to wash off as much of salt water as possible. Sometimes metal brushes are used too and in rare cases anchors and anchor chains may be repainted while the ship is at sea. Usually rust becomes a problem when sailors cannot see important markings anymore.
However, major maintenance is completed when the entire ship comes to a dry dock for cleaning and painting. Then anchor chains are turned end for end, cleaned and repainted. This ensures that these components will continue working for years to come. Sometimes even decades – it is not impossible for the ship to carry the same anchor and chain for the entirety of its service life.
Finally, it has to be said that anchors and anchor chains spend most of their time in the ship rather than in water. They are made from galvanized steel and can be used for a very long time. Merchant ships rarely stand at anchor, because turnover time is what guarantees profit.