: In my never ending quest to re-invent the wheel I'm wondering what the
: effects would be to a kayak...say a wide 20 foot expedition kayak...if it
: was truncated by 4 feet, with a stern treatment somewhat like a wineglass
: wherry. How would it track and paddle? Would it glide...or wallow like a
: water hog. If anyone has an opinion I would love to hear it. Another
: thought...rather than shorten a standard kayak...could a kayak that
: incorporates a wineglass stern be designed with expectations of good
: performance...and looks? Any comments appreciated.

There are some problems with longer kayaks. They are just too low to the water. In flat water you would not have problems, but as the length of the boat increases the greater the likelihood that part of the boat will be picked up by one wave, and the other part of the boat willb e picked up by an adjacent wave.

That usually leaves the center of the boat unsuported by water. Now if the boat is very flexible it will sag until the center of the boat is supported by some displacement. but a boat that flexible will probably track like a wet noodle, as it will also probably flex somewhat to the sides.

Now if the boat is very thin and stiff it might punch through waves rather than being lifted by them. Or, it will bridge the waves. Or, if it is not strong enough to do either of those, then it will crack in half or fold up -- probably at the cockpit area, as that is where the deck is compromised by a big hole. Anywhere the hull collapses could be painful for the kayaker inside.

The longer the boat the worse your problems in this regard. So, longerboats have to be made much stronger to withstand these forces. One common way is to increase the height of the side of the boat. A boat with a side 12 inches high is going to be stiffer, and harder to bend, than one with a sidewall of 3 inches. to avoid the noodle-like tracking you'll want to make the boat stiffer from side to side, as well. This can be accomplished by making the boat wider. Or, youll want a paddler (or power source) close to the front. This could be a fish-shape boat, or a double, or an 8 rower shell.

You can make canoe shaped boats to lengths of 30 feet or more, at which point they will easily hold a dozen paddlers -- and voyageurs used such boats hundreds of years ago. "War" canoes of this size are being built by a few people for camps and re-enactments.

Cut the end off of any of these and you'll have a flat-ended canoe --and there are some which are favored by those who like to use small motors.
But this won't give you that "wineglass" rear end. To achieve that look you need to have the bottom of the hull shaped so that it is pinched in considerably at the stern. This somewhat concave section gives the effect of a skeg, while changing the center of bouyancy forward in the boat. At that point the hull won't be very much like a canoe or a kayak. It will be more like a dory.

Put a deck on a canoe and you have something like a kayak. I think you might look at dories and consider makeing the sidewalls lower and putting a deck on them. It would be an interesting boat. If you made it narrow enough you could paddle it, otherwise you would scull or row it. You could also put a sail or motor on it.

A low dory with a deck and a small cockpit. Hmm. It would look sleek, maybe a bit like a duckboat or a sneakbox, and with the even lower center of gravity the very stable dory design might be enhanced.

Sounds like something you might want to fiddle with.

PGJ