Stuck ships and logs can be pushed by your character. If they are stuck due to terrain you can use the hoe or the pick. If that doesn't work you can use your axe to break the ship or cart, pick up the materials and rebuild it.

You can tow animals with the harpoon.

I think (but am not sure, and will have to test) you can Harpoon a player attached to a cart or boat and tow them. (You and the player have to be in PvP, though.) Reeling in logs would be nice... Wish we could harpoon THEM.