Internal keel for canoe....

Question for you practical physicists: I’ve wondered, but never experimented, with the idea of a strip of lead or some other weighty material attached INSIDE a canoe along the center line. Seems to me it would minimize turnovers by enhancing secondary stability.

There’s got to be something missing in my logic, but

I was absent the day they taught science. Please, no lectures about Proper Paddling Technique Solves All

Problems. Some of us make errors in boat control.

Your weight
at any given height above the CG (center of gravity) would dictate such an incredible amount of counterbalancing weight that close to the CG (close being in the bottom of the boat) that it would be extreme and not worth attempting. There are narrow (relative) sailboats out there with weighted keels and/or bulb keels farther down from the CG so as to provide self righting but in a canoe it would be too wild. You would need floatation in the extreme to counter the weight as well.


We have fun with our boat design thoughts though huh?

Ballast works … with penalties however
You’re right that weight placed low in a canoe enhances secondary stability. Ofcourse it also increases waterline beam and other displacement measures that have various effects. My thought about where to place the ballast for best secondary stability differs slightly from your centerline suggestion. If I were creating a theoretical ballast enhancement with dense weight, I would run it along both sides of the canoe bottom to increase inertial resistance to side waves lifting and twisting the boat on axis. In other words, placing a curved lead pipe along both sides of the bottom (only in the middle, not extending to the ends). It’s like controlling the speed of twist that an ice skater does … out with the arms for slow, in tucked tight for fast. Turning a heavy pipe on axis is easy, but twisting the same weight arrayed as separated parentheses is inertially much more difficult. Many forces and resistances are involved … but low weight DOES generally enhance secondary stability no matter if it’s centralized or separated … just keep it out of the ends so you don’t get into problems with trim, shipping solid water, etc.

It’s been done.
Many folks have added ballast to their canoes and kayaks to overcome “twitchynedss”. I have heard of everything from river rocks to sandbags to shot bags.

Remember: Every pound of ballast added is another pound to be accelerated with each stroke.


different approaches
Don’t forget you have to portage the canoe, load and unload it, etc.

What kind of canoe do you have? Perhaps you could trade it in or sell it and buy one with a wider bottom?

Is lowering the seats an option. Even if it’s only a couple of inches, you’ll gain quite a bit of CG advantage. Might have to adjust your stroke a litle depending on your hull shape.

Personaly, I’d examine other options before adding any weight.

Canoes that right themselves?
I have an older OT Katahdin 16". I have deliberately dumped it in a lake and found that it will right itself even if it is full of water. I’ve also seen aluminum canoes that did this, so the question for me is:

how much gear does it take to counteract this tendency?

It is really hard to paddle a canoe full of water though, and its hard to get enough water out to climb back in adn bail out the remainder.

I knew there were sensible, simple reasons. By the way, it was a hypothetical inquiry-I stay upright almost all the time anyway, and my main problem is

getting out on the water often enough.