Fixing a Hogged Canoe
September 25, 2013
I have an old woodstrip pro-boat canoe that has acquired an inch of hogging due to hanging from ropes at each end, upside down, for decades.
It's an old race boat, 18.5 feet long, 3 feet wide, built to code. Fast and tippy. But nice. Well, nice in its own way. It floats, at least. (And leaks some.)
Hogging happens when the hull it turned upside down and the middle part sags down lower than the ends. So when you turn it upright the ends run lower than the mid-section.
It's the opposite of rocker. Rocker is the amount that the ends are higher than the middle. No rocker means a flat keel that tracks straight until the hull is leaned over and the ends are raised higher in the water or even out of the water. At that point the boat can be readily turned but not until then. The more rocker a hull has the easier it can be turned. A whitewater hull might be shaped like a banana and turn on a dime.
A hogged hull with ends lower than the middle can't be turned at all. If you lean it, the ends still stay well down in the water, grabbing the boat and keeping it going straight.
So we have this old boat that's hogged.
Now, maybe it got the hog built into it because somewhere in its life it got hit by a tornado. It was hanging in a garage that was ruined in a tornado and the boat was badly damaged. The owner repaired it using halfway measures that I can appreciate. He slapped on pathwork as best he could. He shoved the broken parts back into "kinda close" alignment. So maybe the hog has been there since I've owned it, about 20 years. The boat is maybe from the early 80's.
In the pics in this article you might see things about the hull that distract from the story. Like wart-ish looking patches and parts of fiberglass that are cracked or bulging. Ignore all that.
So... the last time I paddled the boat hard with a friend we just couldn't get it to turn on our local river. We had to do 3-point back-up turns a couple times. With the kids I had always been able to make it work OK, but I didn't really care, either. With an adult in the bow the boat tracked like it was on rails. And it wouldn't get off those rails.
I figured the hog is what was causing the trouble and I wondered if I could get rid of it.
I asked a pro boat-builder friend and he said, Well, you could try shortening the thwarts and pinching the gunnels together and that might draw up the ends. That seemed interesting. Then I mentioned the idea to a more science-oriented friend. He said pinching the gunnels would have the opposite effect and would worsen the hog.
I then thought to see who was right by making a paper boat. Like a paper hat. I spread the sides of the paper boat and the ends raised. I pinched them and the ends drooped. Well!
So I unbolted one end of each of the thwarts of the canoe and found that 7/8's aluminum tubing would fit perfectly inside the 1" tube thwarts. I decided that I would make thwart extenders and extra bolt-holes to hold the longer thwarts out at the right lengths.
I also unfastened the seat-brackets and the foot-braces -- all these were limiting the width of the hull.
First I experimented. OK, the hull isn't perfectly hogged. Because it isn't perfectly shaped to begin with. It's a warped creature. It sways up and down a few times. But overall the ends rise up an inch when the hull is turned upside down. I sprung the flexy hull and wedged a chunk of 2x4 between the center thwart and the hull. Then I sighted down the keel-line -- the center got wider but the ends still rose up. So I wedged 2x4 chunks into the bow and stern thwarts instead. Still not perfect. I wedged chunks to widen all 3 thwarts by about 2.5". Now the ends moved right into place!
Then I removed the spacers and tilted the thwarts out of the way and strapped canoe-straps around the hull at each thwart and tightened the gunnels together 2" closer than they were to start with. ...The hog got uniformly worse!
So I went and installed my thwart extenders in all 3 thwarts and the hull now looks pretty good. ...Except for its patchy ugliness and wiggles and wobbles. (I'll work on all that later. Maybe.)
The proof will be in the pudding! I'll cajole our largest teen into going paddling with me tomorrow after school and see if the boat will now go around the corners. If it does I'll be such a happy camper. I know that race boats are meant to go straight but our local river is so narrow and twisty and I wouldn't mind a little re-purposing of my old race boat. It might also be a bit more stable, especially as it is leaned over. The hull downright flares out now. I'm excited to see how it handles.
Strapped hull showing hog.
Strapped hull -- extra hog!
Strapped hull adds to hog.
Thwarts extended -- no more hog!
Old hull -- can ya see the hog?
It's hard to photograph the hog, but there's some showing here.
Thwart showing extension tube widening gunnels by 2.5". (Other thwart also in view.)
Boat from the rear.
"Fixed" boat from the front. It's patchy and crusty, but let's see if it turns better!