Originally posted by Waxior:

harpoon no work, boat no work "boar jump off"

Harpoon works fine. Turn your PvP on.
Get them on the boat, and transport them. Yes, some might fall off during transport. It's a pain, but it's very possible, and I've done it several times myself.

I don't really think this has anything to do with "poor game design." I just don't think you were meant to transport tames, so Devs never thought of including a method for it.