Stand-up Paddleboard Design

Around here -and I guess everywhere-stand-up paddleboarding is a new craze.
Laird Hamilton has teamed with Juan K -designer of several Volvo Ocean racers
including Puma- and they have introduced a new board with the Puma Ocean Racing color scheme and a sort of scaled down VOR 70 "look". I'm interested in what designers and sailors might think would produce the fastest hull shape for such a board. Here are a couple of shots of the Hamilton/Juan K/Puma collaboration. It is a top-end all carbon fiber board, as I understand it. There aren't many pictures available of this board so the hull sections aren't 100% clear:

click on image:

 

Has anyone tried a catamaran/tunnel configuration, at least for flat water? Stability is obviously one of significant overall drivers of paddleboard designs. Paddleboards are generally shallow draft for the beam, so a catamaran might significantly reduce wetted area. Also, an energetic paddler might get above a Fn or 0.3 or so where wave drag becomes significant, but not up to planing speeds, at least not for very long. A catamaran design might reduced wave drag in that speed regime over the usual design.

Drawback to the catamaran configuration would be slamming on the center portion from waves or boat wakes.

 

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David, might be hard to prevent wake reinforcement drag between the two cat hulls since it seems their spacing would have to be pretty close together-I remember something like 50% of the waterline length apart is close to ideal? For a 14' "board" that would be wide....
What about a narrow main hull with two small amas at the aft end?
Wonder what Juan K's design theory is?

 

Good thought about wave interaction. Trimaran with short amas would be a thought. Beam is limited by how far it's desirable for the paddler to reach so for sufficient stability the amas would need to have significant volume. Could be in interesting design and analysis project for someone.

 

If you had a 200lb crew stand 6" off center that would be 100ft.lb. heeling moment. So a one cubic ft. ama 2.5' from the centerline would have a righting
moment of 160ft.lb.. (2.5 X 64=160). The immersed volume of the ama would have to be something like .5 X.5 X 4'-but only when the crew was off center.(!) Looking at it, the ama seems like it would have to be too long since to get that kind of immersion in a low drag shape would probably require something about 6' long, though it could be quite far aft.
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I'm still very curious about Juan K's theory-any ideas?

 

Oh come on. We all know that the dominant factor of performance is power and resistance. The resistance side of the equation is dominated by displacement and wetted surface, not shape.

Wetted surface can't hardly get higher with this JK concept, so don't expect anything there.

The power side of the equation is horribly handicapped by the single paddle that Laird simply can't get beyond.

45 years ago stand up paddling was not that rare, and we knew that double ended paddles were fundamentally required. So until one sees less lame paddles, its hard to even pay attention to the tiny differences between shapes.

 

I'm more interested in what sort of envelope you can move the fore and aft center of gravity as compared to a conventional paddleboard, and what it's like trying to get one of these boards through the breakers.

 

this Stand Up Cat-Kayak makes most sense to me, but

might be a little slower than a feather weight paddle board, if you are feather weight yourself.

http://www.wavewalk.com/

But I think the other features, like inside storage and couple good SEATING positions put it over the top.

As you can see he has tested it in all sort of conditions.

Personally, I'd think about installing bulk heads in at least of couple of hull ends, with screw hatches.

 

What I don't understand is why paddelboards? Are they as fast or efficent as a kayak? Maybe they are better in waves? Here in Seattle they are being used in very flat water. Is this just another Hula Hoop design?

 

Paddleboards are easy for one person to load on top of a car and transport. They provide a better workout than a kayak. They're also easy to maneuver in tight quarters.

 

SUP Design

View of top and bottom of Juan K/Hamilton board :

 

Simple answer for me - different design for different purpose. Kayaks for covering distance, paddle boards for gunning around locally, and the kids love it, and it will surf.

Great workout as well.

 

They also give a different view of the world, especially when used in quiet, reedy, inland waterways. Standing up allows you to see over reed beds and river banks, which is quite an advantage. They appear to be getting popular in our fenland areas for this reason

 

Paddle boards have the advantage over traditional surfboards during long swells as the speed needed to get on the wave can be reached before it breaks. 9/10 a paddle boarder will be "riding" the wave 15ft further out back than the rest of the pack. Very popular here with the big SW'esterlys rolling in.

 

This same debate went on after the "invention" of the windsurfer.The answer was and still is a different shape for different conditions.

The original windsurfer was flat as a pancake with almost no rocker. Many of us (myself included) did a "black plastic bag in the sun wrapped around the middle" modification to soften the board enough to induce a little rocker into the shape. This made the board a little faster in light to moderate air and made turns MUCH faster because you could get the bow up and around easier.

Then when other manufacturers entered the market we saw mild v forms and thinner forward sections as well as a variety of widths and subtle bottom shapes like shallow concave bottoms, w's, etc. All these came with varying rocker.

Then of course the introduction of sinker and semi sinkers for really go fast speeds.

So the answer IMHO is different shapes, sizes and rockers for different conditions and loads. A flat wide board with little rocker for smooth water, perhaps something with a mild V forward for other than smooth water, more rocker if you want faster turns, more of a surfboard shape if you want to surf.

I've used them and as an olde timer windsurfer I thought it was a lot of fun. Here in South Florida and especially the Keys you see so much more standing up and it can be VERY cool to silently paddle across very shallow water and see all the wildlife that you would miss from a kayak or canoe.

Steve