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05/01/2023 05:31PM  
I think this has been touched on here before, but I'm curious to know if anyone can tell me if reducing canoe beam (i.e. shortening the yoke/thwarts) is likely to add center depth? Seems like it would but not finding any info to verify that.

I know it reduces rocker and adds tumblehome but wondering about the center depth? I'd probably only bring it in an inch or two in total.

This would be on a t-formex hull. Thinking about taking a Wenonah prospector 15 and turning it into a dedicated solo River tripping canoe. It could stand to lose just a bit of rocker and would gain from having a bit of tumblehome and a bit less beam in my opinion. Also considering trimming the ends down an inch or two since it won't have the weight of tandem paddlers in the ends I would expect it wouldn't need to be full height.
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distinguished member(2970)distinguished memberdistinguished memberdistinguished memberdistinguished member
05/02/2023 06:53AM  
Are you saying that you are doing this to an existing canoe?

If you pull in the beam, it might start rounding out the bottom but I don’t know what your canoe is made from. On my wood canoes, pulling in the beam rounds out the bottom.

It will not change rocker at all. Rocker is measured from the length of the canoe end to end. That will always stay the same. Yes it will increase tumblehome and maybe depth but not in a natural way and depth might increase due to the rounding bottom and only where you are pulling in the gunwales.

However, the resin is set and cured so pulling in the beam is essentially stressing the hull out of it’s set and cured position. But it sounds like you are going to Frankenstein the canoe so it probably doesn’t matter too much.

Most solo canoes have between 26”and 30” of beam and are around 12” deep at center.
05/02/2023 11:52AM  
As I said, this is a t-formex hull so there's no resin to stress. Pulling in the beam is a somewhat common thing to do with plastic/rx/t-formex hulls from what I gather and already know it decreases rocker and increases tumblehome (rounding it out as you called it). Just wondering how much (if any) center height change has been noticed by those who have done it.
05/02/2023 01:11PM  
Seems like you could measure the center height change with some temporary thwarts. And also check the rocker change which I also think would be zero.
05/02/2023 06:00PM  
bobbernumber3: "Seems like you could measure the center height change with some temporary thwarts. And also check the rocker change which I also think would be zero."

I am planning to measure the change whenever I get around to digging into it. I think I should be able to do a test-fit before I commit to it and should be able to get a feel for how much "slop" there is in the gunnels with the seats and yoke disconnected before it feels like I'm stressing the hull at all. Given the width of the canoe and the newer t-formex I'm anticipating I'll have a good bit of room to experiment with. Though as I said I'm only planning to bring it in an inch or two if it'll allow.

It would actually be great if the rocker doesn't change much at all.
05/02/2023 08:03PM  
Interesting topic; I have also considered this mod on a canoe...but have not been brave enough to pull the trigger. I did slightly widen one however.

Anyway I am on team 'Decreases Rocker'...regardless, it will be interesting to learn what really happens.

Let us know!
05/03/2023 02:09PM  
For what it's worth when I purchased a Blackwater from Savage River John Diller altered the design to add a little more gunwale width forward of the seat to accommodate my dog. He said that adding the width would add rocker to the canoe.
05/03/2023 08:22PM  
Well I went out and took the yoke off the canoe today to see how much flex it has. There's definitely at least 2 inches of give before it starts resisting inward pull and that's with the seat still in. Guessing when I take the seats out it'll have even more.

Measuring the change in height and rocker may be challenging because there's so much flex the the t-formex (i.e. oil canning) when it's lying flat on the ground that it doesn't even sit at it's full 14" height to begin with. Might need to hang it or something to get an accurate measurement, but I feel like that's going to throw the rocker measurement off...
distinguished member (131)distinguished memberdistinguished memberdistinguished member
05/04/2023 01:14PM  
Could you measure the rocker by resting the gunwales on a set of saw horses and a string line set above the keel? Never tried it, just a thought.
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