Identify beach find (pictured)?

Question

See picture: http://picasaweb.google.com/craig.conboy/BeachFinds

I have found a few of these washed up on the beach along the St. Lawrence River. Metallic. Curious about where they come from and what they are used for.

Answer 1

I concur with Dan.

Answer 2

Craig, they look like locking rings. They should be threaded in the hole. They are similar to lock washers.

Regards,

Dan