So rewatching the series, I watch the scene with Luffy mentioning the number of crewmates he wanted. He said, ten crew members. Normally, when counting your friends and family, you don't count yourself. Let go over those who join his crew and what is their roles, shall we?

• Luffy; Captain

• Zoro; Vice-Captain/First Mate

• Ussop; Sniper

• Sanji; Cook

• Nami; Navigator

• Chopper; Doctor

• Robin; Historian

• Franky; Shipwright

• Brook; Musician

• Jinbei; Helmsman

So let say if Carrot and Yamato did join the crew, what can they do for the crew? The reason for this because I'm on the edge of Carrot joining the crew. Yamato... Not so much.