Sags around canvassing tacks

Tim Belcher

I tacked the stretched canvas up to the decks on my first canoe yesterday. It went smoothly by and large, but some of the tacks have noticeable sags between them. I tightened the canvas from end to end (longitudinally?) as I went along, and that helped, and also stretched it laterally with the canvassing tool, but still have a few that seem problematic. In "Jerry's Production Journal" in "The Wood and Canvas Canoe," Jerry Stelmok writes that "when the pliers release their grip, a tiny fold of canvas is formed directly over the fastenings," but he doesn't suggest it's the end of the world. In "This Old Canoe," Mike Elliott first says I need to remove all the tacks, retighten the canvas longitudinally, and then refasten everything. He also says that "small sags between the tacks will disappear when filler is applied to the canvas, so there is some leeway in the process." If I need to retighten the canvas longitudinally, I need to do it before I remove the stretching rig. It does seem to me that the outwale should flatten it out, but I don't want to take any chances with something I can't do over later. Any advice?

Dave Wermuth

Who hid my paddle?
The outwale likely won't make it better. The pucker i see at each tack is what you want. Looking good to me. For larger issues between the fastenings you can wet it and use an iron to shrink and tighten it. I stretch by hand length wise and use a plier crosswise. No problems. Shorter canoes tend to be more challenging than longer. Pulling staples/tacks in areas to re-do is normal.

Rollin Thurlow

member since 1980
There should be a strong pucker above the head of the tacks. I would suggest using two tacks per rib instead of one.
There should not be any slack canvas between the ribs. If there is, it means the canvas was not pulled tight enough, lengthwise, in the stretching jig.
When the canvas is trimmed down to the planking line, 90% of the pucker is cut off. The outside rail will flatten out whats left of the pucker.


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