I can see a problem if there may be an issue of actually going underwater. If so, you'll want some kind of item that will let you breathe, and another that will let you move your normal speed or better. Cloak of the Manta Ray fills both, provides an additional attack form and is fairly cheap (under $8K).
Other than that, though, a good ranged combatant is always a boon to the party. If some winged sunofawyrm comes out of the sky at the ship you're on, its going to be up to you and the spellslingers to soften it up before it lands on deck or damages your sails beyond repair.
And if your spellslinger is primarily fire oriented, it will be on your shoulders to take out anything near the sails- you'll be a lot more precise than someone lobbing fireballs near those big, flammable means of propulsion.
However, you might want to consider something like a throwing weapon enchanted with Returning (and Throwing if you need it and Distance if you can afford it)- or an edged weapon and the Whirling Blade spell- to use when you won't be able to replenish arrows. You'll still get full use of nearly all your archery feats. Might I suggest either an axe of some kind, or if you want to burn the feat, the Greatspear.
A harpoon could also be a good choice.
If you did use my idea about being a Kineticist, a Cryo would be interesting. If nothing else, you should be able to do all kinds of things with the buoyancy of ice you create.
