14' Canoe
Bateau.com offers free plans for a 14' canoe, a very simple two sheet stitch and glue design which can be knocked up in a few weekends. Since I had a few spare sheets of ply collecting dust in the shed it was too hard to resist creating this bit of fun.
Plenty of room for a woolly water dog. The entire canoe is just an open shell, no seats or buoyancy tanks. Of course when fully flooded she has almost no freeboard so could be tricky to bail and board without going ashore. I added an adjustable yoke with a view to single handed portage.
Having low expectations, it was somewhat surprising to find that this boat is in fact reasonably stable, tracks well, and can carry some load. One person is good, two people works with one or both people paddling, three people and a dog did not sink the boat and it could still be paddled (slowly), but it seems that is about the limit.