Planing hull kayaks??

[river runner]

I've seen magazine ads for white water kayaks with flattish bottoms that seemed to be implying that they were planing hulls. I've always assumed that you needed far more horsepower, than a human with a paddle could provide, to get up on a plane.
I'm assuming this is just marketing BS. You can't really get a kayak up on a plane can you?

[Easy Rider]

If you're surfing or sitting on the face of a standing wave you can. Some of that white water stuff gets a bit crazy.

[river runner]

That's it! I feel like an idiot.

[jehardiman]

Yep, surf kayaks can get pretty funny looking.

[cyclops2]

A flat bottom or a V bottom ?

Flat has less, at Kayak speeds in near still water.

[Dirteater]

there a gentleman who surfs behind the paddle-wheel boat near
where I live (in his kayak). He's amazingly good at. it something to see for sure.

[waikikin]

How about one of these http://www.youtube.com/watch?NR=1&v=-VyOZVtOWoI Years ago my dad & I would hook onto the waves generated by game boats like Bertram 35, Cresta 46 up the channel & have a "free" ride for 3-400 meters.

[cyclops2]

With a life jacket on. I do it with a Lowe 16' X 15" high transom Aluminum fish boat & a 9.9 hp. Risky

Dive. Dive

[river runner]

Originally Posted by cyclops2

A flat bottom or a V bottom ?

Flat has less, at Kayak speeds in near still water.

Are you talking about wetted surface area? I thought flat had the most of any design, round the least, and V-bottom would be somewhere in between?

[cyclops2]

I know of no Kayakers near me who can get their SLIGHTLY V hulls on plane by paddleing. I have seen 1 ex Marine dam near get a 10' stripped down cheapy Aluminum fish boat on plane in calm water. The last 7' bottom of the boat is flat. His oars are as long as mine. 6 1/2' each.

If a kayaker had 13' paddle & a Marine. Who knows ? Maybe the V would win.

All the easiest planing boats I have seen are mini flat bottomed 3 point racing hydros or flat bottomed New Jersey racing Garveys.

[river runner]

Yes, I understand that a flat bottom is more likely to plane than a V-bottom, but it sounded like you (cyclops2) were saying that a flat bottom had less drag/wetted surface, at normal kayak speeds, than a V-bottom, which is contrary to what I undestrand to be true. I'm still a bit skeptical that anyone can get anything up on a real plane from just oar or paddle power. If they could, seems like olypic rowers would switch to wide, flat bottom boats.

[cyclops2]

If your back is to the foward direction.
A flat bottom is very erratic in the direction it will travel in. Loads of constant pulling corrections are needed.
Long & skinney hulls do save a ton of energy during a race by going straighter with less corrections.
2 equal athletes. The one in the skinny boat always wins.

[cyclops2]

In slow moving efficient sailplanes.
Is a wide wing more efficient ? Or a narrow but very long, front to the rear end of the wing.

[portacruise]

Two situations which are not kayaks, but might be planing under HP besides hydrofoils.

What goes on with surfboards? Seems like they are sometimes planing while under human propulsion.

What about skipboards, the flat disks you throw like a skipping rock and hop on in shallow water for a free glide ride? This might be some kind of shallow bottom effect though.

Porta

[DCockey]

Originally Posted by cyclops2

If your back is to the foward direction.
A flat bottom is very erratic in the direction it will travel in. Loads of constant pulling corrections are needed.
Long & skinney hulls do save a ton of energy during a race by going straighter with less corrections.
2 equal athletes. The one in the skinny boat always wins.

Another reason, perhaps the more significant reason, that a longer, narrow hull does better in a rowing/sculling/paddling race is the wave drag will be less. That's assuming the length isn't so long that the increase in wetted surface area and correspond viscous drag increase doesn't offset the reduced wave drag.