Hi Joco--
Your canoe is a sponson canoe, but it doesn't appear to me that the sponson construction is the same as that in the picture of the Peterborough you linked us to. Your canoe appears to have a more typical sponson construction... made of cedar and canvas, like two mini-canoes attached to the sides of the mother-ship. Note how bulky the cork sponsons on that Peterborough appear to be... I personally am not enamored of the look... and yet, I do like the look of the more typical sponson, such as on your canoe. Those on that Peterborough look like sponsons on steroids! (I sometimes wonder why folks in "the old days" were so afraid of getting wet...).
When trying to determine who made a canoe, I start with the deck and the general profile of the canoe. Your canoe has a heart-shaped deck. Old Chestnuts can have this shape deck... also several American companies, such as Carleton, Kennebec, Morris, Rushton, Skowhegan... well, many have heart decks... and many with heart-decks can be crossed off the list of possibilities in regard to your canoe because nothing else fits. For instance, your canoe doesn't have a Morris profile or Morris stem.
It's hard to see what's going on with the ribs... are they tapered or are they the same width from one side to the other? The answer to this question may help determine whether the canoe is Canadian or American... so, a good picture of the ribs or a good description is necessary.
Would be nice to have a closer look at the deck. One heart-deck isn't exactly like another... and close-ups sometimes help determine wood species.
I'd like a better look at the thwart-shape. And the flat end of the boat is rather dark and hard to see... I can't tell if it's truncated or original from the pics. Also, a better look at the seats... yeah, they may not be original, but the way seats are hung can say something about who built the canoe, and replacement seats sometimes are attached in the same manner as the originals.
I can sorta see the canoe's profile... but if you're taking more pictures, a nice close profile of the end can be helpful.
There are many different builders, and I'm learning how to pick out a few of them... but other folks here will jump in with their thoughts and someone may recognize what you have, and we'll all learn in the process. Thanks for posting this.
Kathy