Small Boat Design

Discussions around designing small boats including kayaks and canoes.

Coho-with-a-skeg: a report *Pic*

Hi there.

I happen to be a big fan of the Pygmy Coho; I'm now assembling #4. Very well-performing boat with plenty of room for my butt, though it could use more foot room for my size 13's.

However, like many kayaks (all rudderless, maybe?) it is subject to broaching in the dreaded following-seas situation, with the wind and wave action coming from the rear at an angle. In this kind of water, the boat wants to turn into the wind; one can spend a lot of energy in corrective sweep strokes in attempting to maintain a particular heading.

In my case, I generally paddle out of the public marina in nearby Everett, Washington, which happens to be the eastern-most bit of the mighty Pungent Sound. Thus, if I happen to paddle very far out into the salt water (as opposed to coming up the Snohomish River), the return trip is generally in an eastern direction.

...which happens to also be the direction of the prevailing winds in the early-to-middle afternoon on a nice day. Thus, fighting the broach and keeping my heading are frequent, recurring battles, vexing me to no end. I cannot change the geography, so I've given in to the urge to modify the boat with a skeg.

My design sources include the websites of CLC Boats, Peter Carter, and Ross Leidy (who was also nice enough to trade email with me), but I've tried to make it my own thing. In particular, I'm still working out the deployment mechanism.

The photo below shows the skeg in full deployment. It can be retracted to any angle (pivoting at the front corner) right up flush into the keel.

The effect on boat handling has been quite noticable, and pleasing. It reminds me of the couple of times I switched the tires on my cars from bias-ply to radial. There is a sense of increased control and steadiness in keeping my heading.

With the skeg fully retracted, the boat performs as before, which includes a moderate tendancy to turn into a steady breeze, or weathercock. With the skeg fully deployed, the boat responds the other way, i.e., the bow turns downwind. With the skeg partially deployed, the kayak finds some middle course. So, in a variety of conditions (wave direction and height, wind speed, various currents), I've usually been able to find a skeg deployment that just about eliminates the need for corrective paddle strokes.

Any commentary from you all is invited, particularly if you can address the issues of optimum location, shape or profile. Certainly, I am not qualified to speak as an expert about those.

I think, though, that this style is different than those installed on many boats to improve their tracking character. Most of those appear to be long and thin, more like an extension of the keel line, than a protruding fish fin. I'm guessing the fin type produces more drag because it's cross section profile to the direction of travel will be larger.

A deployed skeg makes turning more difficult, of course. I'm also still working on a stern-mounted design which will allow the retracted skeg blade to lie flat upon the deck and going through variations-on-a-theme for the deployment mechanism, to make it easier and more precisely adjustable.

In any event, I'll posit that even a boat noted for its tracking characteristics can get some real benefit from the addition of an adjustable skeg. For more money, of course, a commercially-made rudder system will do the same.

Pete Roszyk,
in Snohomish, Washington - home of the stinky sprinklers!

Messages In This Thread

Coho-with-a-skeg: a report *Pic*
Re: Coho-with-a-skeg: a report
Deployment Issues
Re: Deployment Issues
Re: Deployment Issues
Re: Deployment Issues