Absurd design?

-- Last Updated: Dec-11-04 2:57 PM EST --

Has anyone experimented or heard of what might happen if a kayak design borrowed from the new shaped alpine skis with a wider bow and stern, but slightly narrower midship? I figure it would probably be a disaster on a longer touring boat, but wonder about its' application to a whitewater or surfing style hull. Carved turns? Probably a stupid "think out side of the boat" thought and ready to have holes poked into the hull.

Two Boats???
I would think that the water would see the boat as ending at the mid point thus cutting the wateline in half…

Like two small boats following each other… GH

Savage Fury, early planing hull
designed by Corran Addison:



– Last Updated: Dec-11-04 5:27 PM EST –

What is interesting is that this design came out in 1996, but is now out of production. If it has been around that long I wonder why others haven't played with this concept or there is a reason why it is now out of production? I wonder what would happen if it were stretched out towards a sporting/touring length?

Different concept
Shaped skis work because they flex when edged. A kayak hull doesn’t, nor does it carve turns, except when surfing.

It is my experience that the best way to
turn a kayak underway is to put it on edge with a low brace (like leaning into an eddy). It seems to me that a boat with more width at the bow and stern would be very difficult to turn on edge. Putting a ‘peanut’ boat on edge would lengthen the waterline.

For a touring kayak, the indent in the middle of the boat would create cavatation and reduce speed.

I think it’s a bad design for a boat.

Good point

bigger bow wave
hard to maneuver (deep carving at the ends), more abrupt transition at the end of the stern.

I have serious doubts.

I own a Savage Fury and really enjoyed it back in 96, but felt that the hourglass shape needed to be higher out of the water when paddling. That way you could “engage” the shape when you needed it (surfing, hole riding, etc). So I built two fiberglass whitewater boats using this theory:



They are fun boats to paddle and as you would guess from having wide points behind your hips and near your feet, stable. The shape works without having to flex the boat! :wink:


Straz Kayaks

H2O states
Your talking about H2O in two completely different states. One solid, (your riding on top of it to be simplistic) where reduced area in the middle reduces friction yet still cuts a turn really well due to the width at the ends, and one as water, where hydrodynamics and flow come into play. I personally can’t see it happening. Flow around this curve just to abutt against another one to flow around…

It’s all fun to talk about and play with though…

Powder snow
We don’t see much of that here in the east, but some skiers in the west have days where their skis aren’t making contact with a hard surface at all, but are still benefitting from the hourglass shape. Although powdersnow still isn’t the same as water, it might mirror water’s behavior a bit. I also re-thought Bnystrom’s point about a ski having to be bent as part of the carving process and wondered if a boat’s inherent rocker is really doing what a ski is getting from being bent? Also part of a ski’s purpose to bend besides to help initiate a carved turn is also to act as a shock absorber, which a boat’s design doesn’t have to be quite as concerned about. It is interesting and neat to see that some people have at least tried out this design which up to now I was totally unaware of.

Well I’m glad to have your view.
Seems to be much more informed than mine.

shape/sidecut skis
I’m the guy on the slopes with straight skis (pre-shape era, they actually still have a bit of shape for straight skis). I hate shape skis, I can turn and carve well enough myself thank you, and I an go longer with straights - also faster. My legs tire easier but when I’m tired, I don’t have to worry about veering off into the trees…

There’s a big difference…
…between an 8’ whitewater boat and a 16’+ sea kayak. I doubt that the same profile would work as well in the longer boat.

It all depends…
on where you place the volume. Look at a downriver race kayak. They are 14’6" long and at the water line are 14" wide. However, they add volume above the water line and behind the paddler to create a much wider surface area that allows the boat to carve tight curves when leaned.

Example: http://www.vajdamr.sk/ click on the link for downriver racing.

I thought the purpose…
…of the width high on the hull behind the paddler was to get around the rule that specifies a minumum beam without having a lot of boat in the water or having a wide deck in the way of the paddle stroke? It seems to me that having the volume behind the paddler like that would make the boat more difficult to turn than if the paddler was sitting above the pivot point. Am I missing something here?