>Helmsmen should be NPCs or wand dual-wieldan magic users (of any kind) though; the helm drains all memorized spells and prevents memorizing new spells for 24 hours after use.
OP here, I'm going to drop that element from my version, because I think it's stupid. A clever(?) play on words does not equal good game design.
Currently I'm thinking ships gain the ability to break orbit via a ritual similar to Raise Land. As far as moving about once in space, I'm trying to decide between 'the ether wind does it' and 'a variety of interesting sources of power, including material, dreams, magic, summoned spirits, and dangerous esoteric elements' or both.