when does franky join the crew

Franky joins the Straw Hat Pirates crew in Episode 322 of the One Piece anime, titled "Goodbye my Lovable Followers! Franky Departs." This happens at the end of the Water 7 arc after he and the crew unite against a common enemy. Franky leaves his bounty hunter group, the Franky Family, to become the crew's shipwright and builds their new ship, the Thousand Sunny.