I'm honestly starting to doubt you've ever been on a ship at sea. Being in sight of the shore is going to be of little comfort if your makeshift raft capsizes because of the waves.

Making a boat that can carry multiple people on sea without sinking when the weather goes a little sour (which can happen in less than an hour in the Mediterranean) is a very hard thing to do. And if you know how to do that you'll never have any shortage of metal or other goods in the first place because you end up being the one who trade them for profit.