.,…With no physics background, and no risky-water experience, I’ve wondered: If you fastened a lead strip, say 2" wide and 1/2" deep, along the centerline inside a canoe, would it have the same stabilizing efect a keel has on a sailboat? There must be something I’m missing. (Marbles?)
ballast, yes
It would ballast the boat, thus lowering the center of gravity and making the boat harder to tip. If that’s what you meant by “stabilize,” then yes.
It wouldn’t add a lot of resistance to lateral motion of the boat, unlike a keel. (Only a little, since it would sink the boat deeper in the water.) If that’s what you meant by “stabilize,” then no, or almost no.
– Mark
your weight
as movable ballast would have much greater effect
Lead
One disadvange to adding lead would be that like a keelboat, your canoe would sink if capsized. If you’re going to add ballast it’s safest to only use things that are no denser than water. The easiest is…water. A couple of drybags filled of water & lashed down will help your stability and are a simple way to adjust trim.
don’t
The idea is right in theory, but not practical.
Cosider this :
Even a small drop keel 17 footer will have at least 300-400 lbs of ballast(sub-2000 lb boat), and getting into thousand+ pounds for bigger boats. You’ll add what, 15-20 lbs to the canoe?
Also, the sailboat’s keel has a lot of leverage as we’re talking about something 3-4-5 feet down in the water, not…3-5 inches like the canoe.
I think the most noticable effect you’re gonna get is that the canoe will be much heavier to carry 
Why would a canoe need stabilization?
Nearly all canoes widely available for purchase are quite stable to begin with.
'Mad as a hatter’
or mad as a canoeist?
I like the idea of water bag ballast best.
I’ve glued down some tie points in some of the kayaks to hold down CamelBak bladders.
I don’t think I want to even touch lead much less work with it in any way…but out of curiosity, how would you affix it to the canoe?
I’ve done this with kayaks
I fastened a pipe of lead scraps behind my seat to test this theory. The boat would almost self-right when I laid back on the deck. It was a fun party trick but impractical for touring. Edging was not enjoyable. A typical touring kayak easily has 600 lbs of buoyancy when swamped. I never worried about my boat sinking, but in a canoe, I might.
lead keel
That lead keel would certainly be an asset on portage. Perhaps a paddling lesson instead?
Retractable , hollow bulb @ end of high
aspect keel which you can fill with whatever is handy that day for ballast, sand, rocks etc … empty for portage or re-load on roof.
You heard it hear first > LOL
The lead would work but more so once boat starts to heel over more since it not really too far below waterline given the shape of a canoe / kayak body.
The difference
is tht a sailboat of that design has a great deal o force applied high above th waterline and CG. The lead keel conterbalances some of the knockdown vector of large sails on hih masts.
A paddleboat has little force applied close to the CG. None of the vector tends to capsize. The objective with thse is to minimize weght.
Fill a Dry Bag with Water
Hi Buddy. Haven’t seen you post in a while. You doing well?
Your question struck me as more hypothetical, right? You’re not out melting that tire weight collection are you?
I don’t know the physics either, but know from experience that a load low in the hull can make a boat more stable. If you are really needing some ballast (are we talking about your kevlar solo?) like someone suggested above, a pack/waterproof bag full of water works OK and don’t have to be toted around. You could do two smaller ones to make them easier to handle. Fill 'em when you arrive, dump 'em when you leave.
All the best to you, Tapelgan!
sailboat keels
work well for stabiliztiion because the weight is well below the center of bouyancy. This give a long lever arm for righting the boat. Putting the weight in the keel of a canoe would not have as much affect, and has lots of negative drawbacks already mentioned by previous posters.