Tetsuma sorts through her stuff and packs during breaks. Most of it'll get left behind. Stuff like the practice papers can get used for kindling for the fire (even though it isn't cold out, Tetsuma insists on properly cooked meals - it's unlikely they'll be cooking anything on the ship, after all). One experiment with wood manipulation let her create a rough cloth sack, that their dried food can get stored in.
"You know what I'd like? More clothes. Maybe we can see if one of Captain Sarati's stops has a money-changer and at least a cloth merchant. We'll probably want to pick up some local fashions, too, for sneaking into the castle."