Nonono, Nyan, you missed my point. On a ship, supplies are loaded on board in crates and barrels beforehand, usually by the captain. No single man could regularly carry enough supplies to last an entire boat-ride, considering how far boats tend to go, and how many stops they usually make. All you really need to take with you onto a boat is weaponry in case of an attack, maybe fishing gear, some kind of music or entertainment, and a few personal supplies, if you deem it necessary.

My point of uncertainty lay in whether or not the characters decide to keep their travelling gear in the sleeping or cargo rooms below deck. It would be more logical to sell it for a few extra gold before going on the ship ride to get more supplies, then buy new gear once they get off the boat on the other end of the journey. If you really, really love that one backpack your mother gave you, or that super awesome tent which never seems to leak, I guess it's important enough to list in your inventory.

CURSE YOU SOLAMELIKE! Lol, you posted a response before I did. Now the supply and demand of information is killing this post's value...