I'd hang onto it. There is a very good possibility the game's owner will shortly be allowing people to create rafts or boats.
Otherwise, make 5 signposts I guess, laying claim to the island.
For those in the vicinity of the shipwreck there is a guy called Long Fin Killie, a notorious pirate hunter, in the ship's hold. I'm trying to chop him up but I've run out of APs.
