To pass this stage, all you need are different variations of boats. Below is a quick list.
Set 1: Boat
Set 2: Sailboat
Set 3: Speed Boat
Scribblenauts Remix 3-7 Cheats Hints gallery:
3-7-1-a: Help him off the island!
3-7-1-b: The man needs help crossing the ocean.
3-7-1-c: Give him a vehicle that floats on water.