To make a boat in Little Alchemy 2, you will need to combine several elements and objects.
To start, combine air and water together to create rain. Then combine rain and earth together to create mud. Combine mud and stone to create clay.
Next, combine fire with clay to create brick. Take the brick and combine it with plant to create a wooden plank. Combine wooden plank and wooden plank together to create a boat.
And that's it! With a few simple steps, you've just created a boat in Little Alchemy 2.