The Dashing Sea Train and the City of Water: Water Seven!

After the Going Merry narrowly escapes being hit by a "sea train" which knocks away the giant frog attempting to derail it, the Straw Hats meet the stationmaster Kokoro along with her granddaughter Chimney and her bunny-like cat Gonbe. Kokoro assures the crew that the frog, Yokozuna, was perfectly fine and that it was always testing its strength against the Sea Train Puffing Tom, which connects several of the nearby islands. She also explains that the Log Pose would lead them to Water Seven, a canal city of shipwrights where they could fix their ship, providing Luffy with a map and letter of introduction to the shipwrights' leader Iceburg. The Straw Hats reach Water Seven, the group splits up with Luffy, Nami and Usopp leaving to exchange their gold and rent boats driven by fish-like sea monsters called Yagaras.