Sponsons

[Dave Osborn]

Ya know, most restorers report that a large percentage of the time folks that bring in sponson canoes request to have them left off of the restoration. Well, for me at this game for 15 years plus full time, plus hobby years, I have never had anyone do that. They all want them put back on. Which by the way is not a big deal to me. I assess an up charge for it and nobody has balked. (Maybe I should charge more!)
Now I’ve got an 18’ Old Town Square Stern Canoe in the shop without sponsons, but my customer wants sponsons.
Luckily, I was gifted a canoe that has a good set of sponsons. There is no way they will fit as is. Curves are wrong and they are too short.
I’m going to need to take them apart and re-engineer them on the square stern. I haven’t quite figured out how to add 24 or so inches to the length. Add blocks to the center to stretch it out both ways? How would I figure the height of new blocks? Don’t want a flat looking section.
Anybody have any thoughts?

 

[Todd F]

My thought is that I look forward to the solution. I am not looking forward to restoring my current one but admire your resolve!

 

[Benson Gray]

You should be able to disassemble the current sponsons to salvage the stations. These can then be rearranged and/or reproduced (with some enlargement if necessary) to create the new sponsons with the appropriate shape and length. Good luck,

Benson

 

[Gil Cramer]

I would add the length in the center. After dis-assembling the sponsons, attach the blocks to the ribs temporarily from both ends leaving the center section open. Use the long slats as battens and plank over the empty space temporarily. The battens will make a fair curve. Use cardboard cutouts to determine the shape of the blocks needed for the center. Install the blocks, and plank the entire sponson. If this is done with the canvas draped over the rail, the sponsons won't need to be removed to canvas. I like the transom end block to be parallel to the transom instead of vertical.

 

[Rollin Thurlow]

I guess I would take a bit a different approach. I would use the the center two or three stations and place them at the center three positions of the new canoe. The center station on just about all the O.T. sponson canoes are the same. Place the very last station at where you want the last station on the new canoe and use the middle station in the middle of new canoe. Then run your battens from end to end, if the middle is lumpy reposition the middle one until the battens lay smooth. Then see if any of the remaindering old stations match up. Most of them should be able to be used. Where you need new stations, take the nearest station that is too large, copy it with the cardboard, and start shaving it down until it matches the shape needed to support the battens. The first few tries will take some time but after you get the feel of it, it will go much faster.

 

[Dave Osborn]

Thanks for the ideas guys! Gives me something to go on. Just couldn’t wrap my head around it for a while.

 

[Todd F]

Dave, did you have any luck with the sponson build out?

 

[Dave Osborn]

Todd,
I haven’t done anything yet. Life and hunting season seem to get in the way of much progress in the shop.
It will start happening real soon, though. I’ll post progress.