Richard Clark:

Your characters lack weight to them. Even if they are sitting down, you should see weight to your characters. Think of the "flour sack" animation examples. It's basically the spine and root/hips moving without the limbs. Also, think of the "bouncing ball" exercise. All animation derives from that concept.

And aside from the end shot, the characters just stay in the basic same pose throughout with their heads and limbs moving. I would try and break that up by adding some other motion to it; maybe one is standing up instead, maybe one is scooping water out of the boat or rearranging things in the boat, etc.

Paul Lange:

Nice details, like the boat rocking.