The Trimaran Canoes.

I will build three just shy of 16 foot canoes, as flat bottomed as any Louisiana pirogues. I plan to connect these with eye bolts, carriage bolts and two by fours. The resulting raft will be 16 feet by 12 feet and very stable. Maybe, too stable, we'll see.
The mast rigging will need to be very simple for a klutz like me. I am planning a 14' by 9' triangle sail eventually, although I will start with one 9' by 6' to learn how to sail. I think I can build a good mast with white plastic pipe, string wrapped and sealed with paint to keep it from cracking. Maybe three pieces that slide together for great height? A simple attachment could use eye bolts through the 2by4's, tied to the mast with lashings. A folded painter's drop cloth could be the sail cloth.
I might lay plywood over the 2by4's for a platform that could support my tent when i have no place to land my boat (boats).
A raft made from these three boats would have amazing displacement equal to 360 gallons of water of 3000 pounds. Cutting that total displacement by 25% still leaves a safe load of almost 2250 pounds. If the boats and mast and platform weigh 350 pounds, there would still be room for 1500 pound of payload plus 400 pound of passengers.
The resistance to tipping is 50 to 1. Only a strong wind, full sail, both sailors on the extreme lee side condition might tip this raft. Unfortunately , it will buck like a bull in waves. This might make the waves of a rapid pour over the sides, because the boat-raft will not adjust to standing waves. That could be especially dangerous in class three to five waters.
Just have to see. Good night, daddy.