Originally posted by Apple:

Too bad the game won't let you build chests on a boat

Use ValheimRAFT and you can build an entire ship with multiple decks with storage on every one, if you're into mods(it is not without its problems). Regardless though, I'd recommend having some ore processing capacity on every major landmass you come across. If you always try to take your ore somewhere specific you'll be in for quite the journey later in the game. Those long voyages can make you sleepy