@Sammsy:
gonna answer both parts. first the shipwright. they needed one since day one, if they had one their going merry woudl probably still be able. well maybe not, it seemed bellamy broke it. but they needed a shipwright since day one, just like any crew needs a doctor. they just didn't get one until absolute MUST.
why does BB have a helmsmen? he just does, his crew doesn't affect ours. Hell Foxy's crew has mutliple shipwrights, but i bet all of them combined aren't as good as franky. blackbeard may need both a helmsmen and a navigator, while nami is good enough that a helmsmen isn't needed.
also your fishman with currents? a fishman wouldnt' be able to know any more than Nami unless he went INTO the water, and at that point he ain't much of a helmsmen if not at the helm. also like to point out fishman can not talk to fish, only apprantly jimbei can talk to his own kind of fish. so unless whale sharks are following us around all the time that is moot. I woudl understnad if you said mermaids or mermen. But still though not sure how fish's do in big storms if could even help.
OK so why did helsmen exist in real life? Why if they aren't needed?
Problem is… Job exist in OP world and Oda can write the needing for one like he did with Franky, Chopper and all others.
And really... You think Nami knows more about water than Jinbei? And btw way... You say if Jinbei jumps into the sea he isn't a helsman anymore...
Damn so Sanji isn't a real cook cuz from time to time he is out helping the others and doing something different. Same for the others.
You can debate whatever you want. If it is needed or no. If it will be needed than oda will write that Luffy needs one as well.
Once again.
From all jobs it is the only one which exist in OP world and which isn't in Luffy's crew
Well but it's funny. You people are doing crazy theories all over the place... but saying no a helsman is no needed and Oda did it just for the lulz.
What jobs would the other do?
Boa - bitch of Luffy
Perona - Ok she really could be a lookout (even if others can do it as well)
And please don't come with Zoro, who hasn't a job. he is special cuz he is the first one...
You don't get one thing. It doesn't matter if someone can do it as well... Usopp could fix the ship all the time and was the shipwright but suddenly Franky was needed cuz he is better in it. Same For a Doctor... Do you remember Johnny's and Yosaku's first appearance... A doc wasn't needed and Nami showed knowledge about certain things and was able to heal Yosaku.
Same could happen later.
But if you thing that way... Which jobs the SHs still need?