Mast Lock.

[digsafe]

What dose every one do with them?I have found 3 so far.They go for $30-$40 new.Or is this something they just throw overboard?Thanks.

This is what they look like New.

[JerseyMike]

They're used to keep the mast from coming out of the step in the event of a capsize, they're clamped around the mast below the deck. Which begs the question, why have you found three? Are you near the Bermuda triangle? Guys probably had them on board and not attached, laid the boat over and lost the lock. Is this a back bay area? You could probably sell them easily in a local publication or website in your area devoted to blow boats or at a yacht club, sailing school or rental.