@Drake_Cloud:
Yeah, but he's stronger on land. Jinbe's supposed to be far stronger in the water than on the land, and the size difference is a little much. Remember that Sanji flipped Wadatsumi while he was filled with Air. SJW is probably closer to the size of the entire Fishman island, and its probably mostly fat/muscle.
Being able to breath underwater is probably also a big plus when your enemy can drown people by belly-flopping on them.
Well seeing as how he dealt with that Kraken tentacle, also remember "Anti manner Kick course"? At the end or near end of the story I'm sure he'll be able to do this to SJW.
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–- Update From New Post Merge ---
@Bentham:
Whenever Jinbe starts sailing on the ship I can guarantee you he'll be the one steering the ship -_-
I'm not saying that Jinbe is an amazing helmsman and will make the ship dance with his elite skills, I'm saying that he fits a role that has been mentioned quite a few times when the strawhats have been sailing. Jinbe fits a role in the crew whether you like it or not. What I'm trying to say is that when someone joins there's always been something they are responsible for on the ship, if someone wants to recommend someone then it would help their case if they can point out what they can do for the crew.
Well then we're done here. That's kind of the point.
Brook is an elite musician
Nami is an elite navigator
Sanji is an elite cook
Zoro is an elite swordsman
Chopper is an elite doctor
Usopp is an elite sniper
Robin is an elite archeologist <–------ Pattern
Luffy is an elite captain
Franky is an elite shipwright
Also since Franky built the ship wouldn't he be the most fit to sail it? Its also clear that he can operate various (very futuristic)vehicles efficiently.