Episode 235

"Quarrel in the Moonlight! The Pirate Ship Trembles in Sadness" is the 235th episode of One Piece.

Short Summary
Once they're back on the ship, Luffy has to finally tell Usopp that the Going Merry can no longer be repaired and that they've chosen to get a new ship. Usopp believes that Luffy has abandoned the dignity of their ship and says he's leaving the crew. That night, he challenges Luffy to a duel and whoever win takes the Going Merry.