This is an interesting idea, but you'd have to have some seriously large keys to merit spending $30 on this thing. Foam floater keychain attachments cost about $2, are the same size, and work forever (looks like this is single-use). There's not a whole lot of things on a boat that weigh less than 2 lbs and would survive submersion that you'd want to attach this thing to. Camera? Ipod? If they go overboard you're screwed anyway. And if you've got 2 lbs of keys on your keyring, it's definitely time to get rid of some keys.