Canoe Rocker Rehab

Recently purchased a royalex tandem. I’d been looking for this model for some time and jumped on the boat without looking at it well enough. (It was getting dark, I was supposed to be someplace else already, and, uh, the sun was in my eyes?) So after speeding back to where I was supposed to be, it hit me. What had been nagging at me was that the canoe didn’t seem to have the right amount of rocker. At home the next morning daylight and a straight board confirmed the fear that the poor little thing was slightly hog backed.

A foam pillar under the yoke takes out the minor hog back, but the canoe still doesn’t seem to have the expected rocker.

Will pulling the gunnels in by shortening the yoke likely increase or decrease rocker? Any other thoughts for increasing rocker?

This boat will likely just get some tlc and be sold for what I’ve got in it if I can’t get the rocker back, because that was what had me focused on this model to begin with.

Seems like pinching
the gunnels would have the opposite affect - widening a bit might help? No?

widening might help
There have been a number of threads here and on cboats dot net regarding the effect, or lack thereof, of modifying gunwale beam on boat rocker.

The conventional wisdom is that widening a canoe might have the effect of increasing rocker and narrowing it the opposite effect.

Some folks have noticed a change in rocker and others have not. I have pulled in the gunwales on a couple of Royalex whitewater canoes up to about 2 inches and I have not seen any change in rocker that I could see, measure, or otherwise appreciate. These were older Royalex boats. It might be that a newer Royalex boat that is less “stiff” might demonstrate more of a change or maybe there is some time delay between narrowing a boat and a change in rocker.

What I have gleaned is that the general consensus is that relatively minor changes in beam (2 inches or less) have relatively little effect on rocker in Royalex boats but might have more effect on the cross sectional hull configuration. Widening a boat might flatten the hull a bit and narrowing it might put more arch in the hull bottom.

You can certainly try spreading the gunwales a couple of inches using either bar or pipe clamps that can function as spreaders, or maybe just some furring strips cut a couple inches wider than the yoke and thwarts to push out the gunwale a bit, and then put a straightedge back on the keel line and see if it is different. My guess is that you will get more mileage with a foam spacer between the hull bottom and yoke though.

I have paddled a number of Old Town Discovery canoe which tend to become a bit hog backed with age. Many will probably take exception with this but personally I haven’t noticed any great hardship imposed by a relatively minor degree of hogging.

This all make sense to me.
The only thing I would say on the hog back impact is this - I have noticed in the Discovery models I paddled that they seem slow - and they were all hog backed. Don’t know if there is a connection - but there might be. I recall one trip when we had two rentals - one discovery and one nova craft royalex. Both about the same length. The difference in speed was significant, so we agreed to switch off boats half way through the trip.

I Pulled Gunnels In On a Couple Hulls
To DECREASE the rocker. Made a slight difference. I know it seems backwards, but you have to LENGTHEN thwarts to increase rocker. And some hulls may or may not show much difference. BTW, Rob, what IS the boat? Pics? Merry Christmas, my friend!

Trade Offs
Thanks to all for the shared wisdom.

The foam pillar seems to be taking out the hog back at least somewhat.

I’ve got the portage yoke shortened 2 inches, which certainly seems to have put the arch back in the shallow arch hull. I’ll keep playing and see how it looks and paddles.

It could be wishful thinking but maybe the canoe is gradually drifting back to a remembered shape.

May be able to sneak off for an hour or two at the lake tomorrow and will see how the little tandem solos into the predicted gale.

Terry, I’ll stay coy on what it is for now. Merry Christmas to you and yours.

The prognosis for a hogged canoe is usually not good. Some people talk about ratching down boats on their roof carriers, a bad idea.

There may be some hope for a Royalex boat. They have lots of memory. Put the boat in a really warm location and encourage it back into shape.