Keel Reality

Decked Canoes, Open Canoes, as long as they're canoes!

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riverman
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Keel Reality

Post by riverman »

OK, so how much effect does an external keel really have on a canoe (or other paddle boat)? There's a lot of hyperbole out there about how it helps tracking, makes it hard to turn on flatwater, etc, but I think most everyone is regurgitating what they have heard or want to believe. Can anyone point me to some real empirical evidence, or can provide some REAL first-hand experience to justify one point of view or another?

I can't. Even though I have thousands of miles of OC experience, I cannot state that I have ever felt that a keel had any significant impact on boat handling, either way. Certainly other factors play a big part, but I've never run two identical boats, one with a keel and one without, so that the effect of other factors could be eliminated.

Maybe someone here has cast up a boat without a keel, noticed how it handled, then put a raised keel on and felt the difference?

--riverman
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awelch
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Keel

Post by awelch »

I have never run an oc with a keel, but, I paddled a deep v rec kayak my first season of whitewater and by the end of the season it had a hole worn through it on the deep v part from the concentrated wear. It was also hard to turn. I learned to use eddie lines to turn it by the end of the season.

I think that the wear isuue would be the same on a keeled boat. I went to a Nitro this year and would never go back to a keeled situation for white water. Too hard to manuever and that was only in slightly technical class II.
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sbroam
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Post by sbroam »

Could you take a strip of minicell and make a temporary keel? It wouldn't survive rocks or maybe not even sand, but it should give you an idea of how it affects tracking. I know a local paddler who made minicell skegs that he attached to his kids boats to help them out when they were learning to paddle (though they in kayaks).
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philcanoe
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Post by philcanoe »

just quessing...

but wouldn't it be hard to float over rocks, any direction but dead ahead, like sideways ???
...sounds rather tippy, if not in big volume

and wouldn't it inhibit rapid turning/spinning boat around???
....which is most critical thing in keeping a boat dry
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Post by John Coraor »

I don't even know if they still make them, but in the 50s a shoe-keeled 15 ft. Grumman aluminum was THE WW boat. If you can find one, you could compare it with a standard lake-keeled 15 footer. While not entirely a keel vs. no keel situation, you would be comparing a substantial keel (probably 0.5-0.75") with a much smaller one (probably around 0.125-0.25"). Neither one would be a particularly desireable WW boat in this day and age, but at least you would have an apples to apples comparision.

John
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Post by jscottl67 »

I'm pretty sure that a keel (depending on varying factors) would have some impact on a boat's handling. That said, I think a keel is one of several design factors that come into play.

I've got a 17' boat without a keel, but it has no rocker at all and the ends are very abrupt and upright...pretty much the full length of the hull is in the water. I've paddled 16' boats with a keel, but with a bit of a rise and a rounded entry that turned easily by comparison.

You could probably add a low keel to a short, highly rockered boat and it would probably still spin and turn fairly well. A lot would probably depend on the bottom of the boat...a flat hull or a shallow arch. I think the biggest issue on a WW boat would be that it would be the impact/hang up issue. Could make the boat pretty tippy on rocks, etc. ;)

On some shorter general purpose canoes, I've seen a reverse keel...basically a groove where a keel would be. It adds some structural rigidity to the boats and probably has some impact on keeping it straight. A couple of lengthwise grooves on a WW boat might me interesting :)
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Re: Keel Reality

Post by Randy Dodson »

riverman wrote:OK, so how much effect does an external keel really have on a canoe (or other paddle boat)? There's a lot of hyperbole out there about how it helps tracking, makes it hard to turn on flatwater, etc, but I think most everyone is regurgitating what they have heard or want to believe. Can anyone point me to some real empirical evidence, or can provide some REAL first-hand experience to justify one point of view or another?

I can't. Even though I have thousands of miles of OC experience, I cannot state that I have ever felt that a keel had any significant impact on boat handling, either way. Certainly other factors play a big part, but I've never run two identical boats, one with a keel and one without, so that the effect of other factors could be eliminated.

Maybe someone here has cast up a boat without a keel, noticed how it handled, then put a raised keel on and felt the difference?

--riverman


Several years ago, my wife and I went canoe camping on the Current River in Missouri. It is strictly class I or less but moves along rather swiftly with plenty of sharp turns and eddies. At the time all we had were solo whitewater boats and one tandem Whitewater boat, so we borrowed a canoe from a co-worker. It was a Coleman :oops: Ram-X-15 with a keel. Manuverability was zero. These days we can paddle that same river in our Wenonah Spirit II which is 2 feet longer but has no keel and manuever five times better.
To this day, our children think that they are called STUPID KEELS.

I realize this may not be apples to apples but I'm pretty much convinced that keels have about as much effect on your manuverability, as pulling a swimmer has on your ability to paddle forward.

lessons learned: No keels on rivers and always wear a bag over your head if you have to paddle a Coleman canoe. :D
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sbroam
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Post by sbroam »

But is wearing a bag on your head as bad as wearing nose plugs?
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Post by jscottl67 »

paper or plastic? :P
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philcanoe
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Post by philcanoe »

ditto on Randy's story... about the Coleman ... have a similar story

a buddy's boat, the best thing besides the price, was that the keel worn out because of excessive rock contact
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Post by Sir Adam »

They do have an impact, even small skegs. I'm not sure if I'd notice the difference a skeg makes (and I'm talking about the race-legal WildWater race boat skegs here, not the sea kayak version), but I'll let you know if I ever get to paddle an Ace III with a skeg, or a Bala without one:).

Open boat wise, in my flatwater experience I've felt a difference, mostly with inexperienced bow paddlers (with a keel it was easier to keep the boat going straight despite what they were doing). Could have been my imagination, though.

I'll take a race boat with no keel any day over anything else...but that's because I lean towards fast, narrow boats that are light (hence the Maven...).

Any curvature over / in a flat surface will indeed help to stiffen the area...hence a lot of the curves on the decks of plastic boats, as well as ribs in many boats, and the raised area in a lot of boats in the hull (whether or not it translates to a groove in the hull "skin" itself).
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Post by Eric Nyre »

Two ways to test the theory:

Prospectors are a fairly common design, often built with and without keels. Paddle a 16' Prospector with a keel, then switch over to the non-keeled version. You will feel a difference!

Sea kayaks often have drop skegs, which are almost like adjustable keels. They're a fin just behind the cockpit that can be raised or lowered by a deck control. At 1/4 skeg (about 1" down fin) there is a change in handling over no skeg or full skeg.

As for the Grummans with the shoe keel, that was the river boat and the standard keel was the lake boat. It's not that keels are good on rivers, it's that a Grumman is rivited together and needs a keel to hold the hulls together. The shoe keel was minimal, just enough to hold the sides of the boat together.
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colemans

Post by oc1paddlr »

I'd wear a bag over my head if I ever looked at a coleman on a river. Way back when I had a buddy in one who got his leg from the knee down pinned between the internal frame and the hull. THAT is a steaming pile ...!
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KNeal
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Post by KNeal »

Thanks for joining us on cboats, Riverman. You asked a good question by challenging what may be a myth/misconception or a basis in fact
what they have heard or want to believe.
If you have not come across the empirical data through the internet or the thousands of miles you've paddled to satisfy your level of understanding of the efficiency of a keel, I thought of a REALLY great test you can conduct that WILL help you draw your own conclusion! Yay! :D

Take 4 17-foot canoes onto a lake (gotta be a lake for this test). They all should be straight with no or little, but equal, rocker along the bottom and 2 need to have a keel running the length of the hull (down the center, of course). Launch each boat onto the lake on a really windy day with one person, with a canoe paddle, per canoe. Each person is tasked to keep the boat sideways to the wind by light bracing and very little steering (to minimize influencing the test :o ) and to keep the boat flat (no tilt). Let the wind push the boats for a given, and measureable distance (say about, 1/2 mile) and see which boat(s) reach the finish line first! Bring the boats back to the starting point and have persons rotate to a different boat and do the drift/wind test again. Complete the test 4 times so each person has been in a different boat. Compile your data on the first boat finishing each test and see if the one with the most finishes has a keel or not! Results of the test will be best measured under windy conditions with winds speeds around 15-30 miles per hours and small variable wind gusts. Wind speeds slower than 15 mph will make the tests VERY boring for the volunteers and wind speeds higher than 30 mph will begin affecting the drag coefficient resulting from boat tilt forcing the leeward chine/edge of the canoe underwater.

Let us know what you, or anyone else who wants to conduct the test, find out! :D

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riverman
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Post by riverman »

You a funny man KNeal. :D

Actually, I was thinking more along the lines of finding a couple of models of canoes, making a small keel along the bottom of one with clay and/or duct tape, then giving them a gentle push to see if the keeled one tracked straighter repeatedly. Likewise, giving them a spin and seeing if one turned easier.

My guess is that, IRL, so many other hull shape factors play a much more significant role and that keels are actually just an artifact of early canoe construction.

Anyway, I certainly see a marked difference in how we single-bladers discuss this than the double-bladers over at boatertalk. :-)

Its nice to be among family. :wink:

--riverman
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