You can’t totally prevent corrosion on board as the environment itself are agents of corrosion.

Even if the anchors are seldom used, the chain inside the chain locker can be pretty well corroded- at least on the surface.

The only way these chains get a total makeover is during drydock operation where it’s taken out from the ship, inspected, derusted, repainted and all its markings refreshed.

On board, we do make some effort to remove the rust. One method is to drop the anchor up to the 10th or eleventh shackle controlled by brake. You can see the rusts fall off instantly on deck and into the water.

Another is to manually chip and paint the chain. However, we only do it on the part with the shackle markings so we can read it during the night.