This is right after the part in the stars. When you're inside the boat.
- Go to the bottom floor, get a cannon ball on the left.
- Use the cannon ball on the barrels of oil.
- Go up one floor and use the oiled cannon ball on the bottle shards on the floor.
- Get the long stick.
- Go to the top floor, ring the bell and go stand next to the cannon.
- When the guard (who is unusualy calm considering his boat is attacked by a kraken...), is on the top floor, get the rope in the chest that was behind him.
- Use the stick on the cannon's barrel.
- Put the cannon ball inside.
- Push the lever.
- Use the fuse on the back on the cannon.