Well, you do have a challenge ahead of you!
Basically it is something like this,
1) Remove sponsons. Repair the boat and the sponsons as needed.
2) stretch canvas over the area where the sponsons were. Fill the canvas.
3) Reattach the sponsons. the last plank on the sponsons is tapered to a feather edge so the sponsons planking will flow smoothly into the hull of the canoe.
4) Trim the bottom canvas so it is not exposed. On the top, leave enough canvas so it can be folded or rolled over the top the sponsons.
5) Canvas the whole boat. The top edge of the canvas will be attached to the top edge of the sponsons (not at the canoes rail).
6) fold the top edge of the canvas that is sticking out from behind the sponsons and fold it over the top edge of the sponsons so that it coverers the top edge of the canoe hull canvas.
7) A outside "trim rail" or "sponson cap" will cover the canvas lap..
8) Sand, paint, sand paint sand paint, varnish, sand ,varnish, paint and varnish again and your all done!
Picture 115- canvasing under the sponson area.
picture 118 - installing the invisible sponson. The last plank on the sponson is feathered to be smooth with the hull. the excess canvas will be trimmed to the feather edge.
Picture 131 - the sponson canvas is rolled over the top of the sponson. The outside hull canvas is trimmed to the top of the sponson. In the picture you can see the canvas lap on the edge of the sponson.
picture 134 - Applying the trim rail that covers the canvas lap.
Picture 141 - the finished boat.
There are different variations of canvasing inviable sponsons but they all require the sponsons to be removed, canvas put underneath, reattach the sponsons and then recanvas the whole ball of wax!
