Non-spellcasting ranger (variant from Complete Warrior.)
Swashbuckler (a little underpowered, but in a setting with lots of seafaring -- and thus lots of chances to fall in the water and drown -- don't underestimate the benefits of being lightly armoured.)
Rogue
Scout
Fighter (not so bland if you pick the right feats.)
Hexblade, if you're willing to put up with a smidgen of spellcasting (and going by the presence of an artificer you probably are.)
Ninja can actually work well, all joking aside.
Marshal might be good to represent the inspirational captain.
If you're using barbarians, I'd definitely look at some of the alternate totems in Unearthed Arcana.
And, of course, you should probably check out Stormwrack to see if they have any useful substitution levels/alternate class abilities.