A nut is a forged ridge or block protruding from the side of an anchor's shank, located just below the square hole where the stock passes through. It acts as a physical stop, preventing the stock from sliding down the shank when the anchor is deployed or retrieved. This ensures the anchor maintains its geometry to bite into the seabed properly.
Heard on the job
Inspect the shank near the nut for hairline cracks; that area takes a lot of stress when the stock catches the bottom.