cutouts wingfoil boards

[StellaBlu]

With all the focus on planing in this design and others, its interesting to see how downwind paddle boards are moving towards narrow deep V profiles (see the newer Kalama designs). I think the idea is consistent with what @tkaraszewski and I have said - planing speed is actually faster than foiling takeoff speed for a wing board or a paddle board and therefor irrelevant. While most boards are still designing around how to most efficiently reach planing speed - that design philosophy is a fallacy and a Deep V profile may actually reach foil takeoff speed faster than a flat planing hull.

All that said - a deep V is extremely unstable, and potentially impractical for a wing board. While a flat hull may not be the fastest to foil takeoff speed, it might be the best compromise of speed/stability. Note that planing speed is entirely tangential to the design though.

[jakemoore]

Fanatic 2021 wing boards had double concave hulls but are now completely flat in 2022

For 95L: Flat out the back - small convex belly in the front.

[Peter_Frank]

With all the focus on planing in this design and others, its interesting to see how downwind paddle boards are moving towards narrow deep V profiles (see the newer Kalama designs). I think the idea is consistent with what @tkaraszewski and I have said - planing speed is actually faster than foiling takeoff speed for a wing board or a paddle board and therefor irrelevant. While most boards are still designing around how to most efficiently reach planing speed - that design philosophy is a fallacy and a Deep V profile may actually reach foil takeoff speed faster than a flat planing hull.

All that said - a deep V is extremely unstable, and potentially impractical for a wing board. While a flat hull may not be the fastest to foil takeoff speed, it might be the best compromise of speed/stability. Note that planing speed is entirely tangential to the design though.

I dont get it?

A deep V (assume "deep'" means a lot of V) will always require more power than a flat or concave bottom to get planing/foiling, but might have less drag once planing on the surface (but not relevant for foils), and the advantage is for surfboards if you want superfast rail to rail transitions (not relevant for foils either).

Thus you hardly never see any boards with this - except for really high wind boards maybe, or big wave surf guns

Peter

[StellaBlu]

With all the focus on planing in this design and others, its interesting to see how downwind paddle boards are moving towards narrow deep V profiles (see the newer Kalama designs). I think the idea is consistent with what @tkaraszewski and I have said - planing speed is actually faster than foiling takeoff speed for a wing board or a paddle board and therefor irrelevant. While most boards are still designing around how to most efficiently reach planing speed - that design philosophy is a fallacy and a Deep V profile may actually reach foil takeoff speed faster than a flat planing hull.

All that said - a deep V is extremely unstable, and potentially impractical for a wing board. While a flat hull may not be the fastest to foil takeoff speed, it might be the best compromise of speed/stability. Note that planing speed is entirely tangential to the design though.

I dont get it?

A deep V (assume "deep'" means a lot of V) will always require more power than a flat or concave bottom to get planing/foiling, but might have less drag once planing on the surface (but not relevant for foils), and the advantage is for surfboards if you want superfast rail to rail transitions (not relevant for foils either).

Thus you hardly never see any boards with this - except for really high wind boards maybe, or big wave surf guns

Peter

You missed the point entirely. A deep V doesn't plane. And neither does anybody getting up onto a foil with a wing or a paddle.

[Peter_Frank]

IMO it doesnt matter if you get planing or not...

You are saying a long V shape would be the best?
As agree it has the lowest drag, just like a kayak, when not planing and just gliding straight.

But a wingfoil is pumped into planing - and here, IMO, a deep V will be very bad, as you can not pump into foiling because it just sinks into the water instead of freeing the board from the surface.

I believe this is more important, than low drag when gliding non planing straight out.

An interesting idea though, and totally opposite ideas

Peter

[bragnouff]

I think there's a misunderstanding of the "deep V" idea...

Here are Kalama's wing/SUP boards. Same thing for the downwind/prone range, although they are a bit more streamlined, more length, narrower.


https://kalamaperformance.com/product/e3-foil-wing-sup/

Anyway, the deep V you mention is a pointy bottom hull tail, and the hull surface looks flat ( i.e. no multi concave, no V ...), which seems to be aimed at reducing drag, increasing displacement/sub-planing speed

However, .... How much can you trust a middle aged man wearing Crocs on marketing material?

[StellaBlu]

I think there's a misunderstanding of the "deep V" idea...

Here are Kalama's wing/SUP boards. Same thing for the downwind/prone range, although they are a bit more streamlined, more length, narrower.


https://kalamaperformance.com/product/e3-foil-wing-sup/

Anyway, the deep V you mention is a pointy bottom hull tail, and the hull surface looks flat ( i.e. no multi concave, no V ...), which seems to be aimed at reducing drag, increasing displacement/sub-planing speed

However, .... How much can you trust a middle aged man wearing Crocs on marketing material?

The new prototypes of these boards are much more radical. More V, skinnier, longer, displacement hull. These are the boards that Dave has been prone paddling into unbroken windswell - so clearly they are extremely efficient. Check instagram for these.

[StellaBlu]

Double post - Deleted

[bragnouff]

Sure, just checked his Instagram videos, definitely looking more like 14' race paddleboards, long, narrow, some V on the nose section, and steep rail chines all the way to the tail tip, like on the E3 picture above. All about displacement performance, allowing to reach speeds where foil will start lifting.
But still it's not what we commonly refer to as V on a surfboard or windsurf boards.

While incredibly efficient and opening possibilities like downwind prone, that extreme form is probably of marginal interest for wing foiling where there is more ambient energy to tap into, and having a small compact board once up on the foil is very important. Hence why his production line of wing boards uses some aspects of that design (rails, tail,...) but not the extreme long and narrow dimensions.

[Trent hink]

I don't get the cutouts. My kite foil takes off way sooner than the board has a chance to plane...

The winging foils I see being used, even on "sinker" boards, are way larger and usually higher aspect.

There must be some bottom shape that is ideal, but it seems at this point it's still a question.

In my mind, at the very most, the board only has to go fast enough for the foil to start lifting...

At which point it should then be designed to be easy to pump up onto the foil.

I would think this requires a very hard edge somewhere pretty near the tail of the board....

What about a totally different approach?

The maximum speed of a displacement hull is pretty slow…

Your 1.8 meter board is maxed out at about 3.25 knots at displacement speed.

But really narrow hulls break the rules and can go faster, and a really narrow hull would also have little drag even bouncing it up and down to get on the foil, which seems to be the whole point in the first place.

It seems so obvious, that I must be missing something…