After gronking my knee a few years ago, I had to give up my Zealot, and even the 7.5 inch seat in my Wide Ride was causing too much pain and poor circulation. But the knee has recovered, and today I was messing with both boats in the basement, doing whatever I could to make paddling bearable.
One thing I learned is that pain is not a simple function of seat height. There are some other details about how the knees are spread, and how the feet lie on the bottom of the boat, that have more to do with comfort than I expected.
I have always used foam knee blocks to spread my knees. If I don't do this, if I rely only on knee cups and thigh straps, then I get a strange kind of knee pain evidently caused by sheer forces inside the joint. With knee blocks, this pain is absent.
I've tended to use fairly wide knee blocks to spread the knees for control and to get my thighs out against the inside of the cockpit rim for more positive rolling and control.
But now I realize that I've been trying for too much knee spread. No c-1 has a perfectly flat bottom, and the more roundness there is, the more the bottom of the knees are raised relative to the lowest point of the boat, and relative to your feet. The farther out to the side your knees, the more your knees will be flexed. Think about it and you'll see why.
So in my Zealot, after raising the seat height to 7", I still had a lot of pain on entering the boat. So, seeing the probable effect of my knees being spread to wide, I carved the knee blocks back about an inch. The result was a marked improvement in knee comfort.
Next, it occurred to me that if the knees are spread, then the feet want to be closer to the center of the boat. So I pulled the Zealot seat out and carved deep pockets in the trailing foam slabs (which locate the seat along the rear wall) so that my feet could lie where they wanted. This also resulted in less pain cramming into the boat. (Note that, at 6' 5", I do not have a prayer of getting my feet up on my toes or using toe blocks. The tops of my feet lie flat on the bottom of the boat.)
Next I went over to my Millbrook Wide Ride and tried it on. The knee spread was not excessive. The trailing part of the seat pedestal did not need carving. I decided the seat could stay at 7.5". I would like the seat higher, but the Wide Ride does not have nearly as much initial stability as the Zealot, and might feel spooky with a higher seat.
I want to add that improperly placed thigh straps can also cause knee pain. The worse the placement, the harder people crank the straps down to compensate, and the more discomfort. For the best comfort and control, the strap attachments should (IMHO) be about 6" forward of where your butt bones sit, epoxied to the seam; this may put the upper strap attachments a bit back of the cross-center of the cockpit. The center attachments, on the bottom of the boat, should be maybe 5" to 6" back of where your knees sit in the cups. This is where Adam Clawson had the attachments when he sold me the Zealot, and it is just right. The straps pass diagonally over the tops of my thighs, which distributes downforce for comfort and maximizes support when one is upside down.
Those confronting the outfitting of a c-1 for the first time tend to have the lower, central strap attachment points too far back, so that the straps pass almost at right angles to the thighs. This makes it harder to thread one's knees into the boat, and more (painful) downforce is required than with the diagonal orientation. My Wide Ride, bought used, had the crossways strap orientation, but I was able to correct it without putting in new attachments by putting heavy Tygon tubing around the attachment webbing to force the lower strap attachment to the forward extreme of its range.
Pain boaters face two kinds of pain. One is initial pain associated with struggling into the boat. It may subside, but with proper outfitting, it can be made to go away.
The other kind of pain is the kind that grows after a half hour of compromised circulation. It isn't as dependent on outfitting. Get out of the boat and shake it off.
I don't know whether I will be able to paddle c-1 seriously again. At 64, I have to treat the issue of ischemia and thrombosis in the legs more seriously. But all these issues also apply, to a lesser extent, in my open boats. Maybe all these fussy details will help someone; hope so.
