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Shorter board is less playful...!

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AndersP
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Re: Shorter board is less playful...!

Postby AndersP » Fri Jul 03, 2020 1:53 pm

Kamikuza

The pivotpoint i not where mast meets the fuselage. It is in front of the frontwings lifting center since the stab is pulling down. Try to to foil with both feet right where the mast is and you will see.

Many pocket boards have the mast almost at the back end of the board.

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Re: Shorter board is less playful...!

Postby Frankieboy » Fri Jul 03, 2020 6:40 pm

I went from a 120cm board to a 37" Kanaha Shapes (94cm) and I can assure the turning speed and versatility is way better on the small board.

I had to fix this front foot pressure though (Moses 633 with 450 stab) or the KS was unridable. With the 425 stab (no shim) the balance is perfect but 450 is better in waves.

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Kamikuza
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Re: Shorter board is less playful...!

Postby Kamikuza » Sat Jul 04, 2020 3:00 am

AndersP wrote:
Fri Jul 03, 2020 1:53 pm
Kamikuza

The pivotpoint i not where mast meets the fuselage. It is in front of the frontwings lifting center since the stab is pulling down. Try to to foil with both feet right where the mast is and you will see.

Many pocket boards have the mast almost at the back end of the board.
Wherever you can stand with your feet side-by-side is the "pivot point" of the system, and that seems to be pretty much right on top of the front wing. Which, unless you've got a windsurfer foil, is a couple of inches ahead of the mast.

So the mast mount on the board becomes the pivot point for rider input.

Narrow your stance as much as possible, or move your mast all the way back, then see how quickly you can react to an increase or loss of lift. There's a reason race boards have the centered strap behind the mast...

Many pocket boards are designed wrong :D

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Re: Shorter board is less playful...!

Postby Peter_Frank » Sat Jul 04, 2020 9:23 am

Kami, you are right the balance point is where you can stand feet side by side.

But you are very wrong about the mast connection being the pivot point.


AndersP is right :thumb:

On a stabless foil, the pivot point is around 30 % from the leading edge of the front wing.

On a normal foil it is maybe 10 cm further forward, close to the front of the wing.
Because the stab moves the system COE forward.

Also, the pivot point is under the water, at the very wing, not on the board, and never ever the mast.

It does not matter in this respect, where the mast is positioned, forward or rear of the wing, the pivot point is at the same spot on the flyer (flyer = frontwing+fuselage+stab)

The balance point on the board is pretty much just over the pivot point of the flyer, so around the front of the front wing usually, maybe a tad more rear when riding powered because of the wing drag and lever effect :D

I always have my rear foot behind the mast, as I don't like narrow stance.

If I put it on top of the mast, I would have a really narrow stance on most hydrofoils :x
But some like this, we are just different :D

8) Peter

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Kamikuza
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Re: Shorter board is less playful...!

Postby Kamikuza » Sat Jul 04, 2020 12:06 pm

Peter_Frank wrote:
Sat Jul 04, 2020 9:23 am
Kami, you are right the balance point is where you can stand feet side by side.

But you are very wrong about the mast connection being the pivot point.


AndersP is right :thumb:

On a stabless foil, the pivot point is around 30 % from the leading edge of the front wing.

On a normal foil it is maybe 10 cm further forward, close to the front of the wing.
Because the stab moves the system COE forward.

Also, the pivot point is under the water, at the very wing, not on the board, and never ever the mast.

It does not matter in this respect, where the mast is positioned, forward or rear of the wing, the pivot point is at the same spot on the flyer (flyer = frontwing+fuselage+stab)

The balance point on the board is pretty much just over the pivot point of the flyer, so around the front of the front wing usually, maybe a tad more rear when riding powered because of the wing drag and lever effect :D

I always have my rear foot behind the mast, as I don't like narrow stance.

If I put it on top of the mast, I would have a really narrow stance on most hydrofoils :x
But some like this, we are just different :D

8) Peter
I'm sure if you could alter the mast to wing mounting length, and then the foil mounting point on the board, that it wouldn't feel or respond the same. Virtually, it'd be identical but the response from the board would feel different.

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Re: Shorter board is less playful...!

Postby Peter_Frank » Sat Jul 04, 2020 4:09 pm

No, not in terms of pitch or balance/pivot point, would be and feel the same.

But directional stability and turning dynamics would be really compromised indeed :wink:

8) Peter

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Kamikuza
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Re: Shorter board is less playful...!

Postby Kamikuza » Sun Jul 05, 2020 3:48 am

Peter_Frank wrote:
Sat Jul 04, 2020 4:09 pm
No, not in terms of pitch or balance/pivot point, would be and feel the same.

But directional stability and turning dynamics would be really compromised indeed :wink:

8) Peter
And all we ever do is pitch the board, right? :roll:

Neither does the board pitch around it's virtual pivot point right down there are the wing...

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Peter_Frank
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Re: Shorter board is less playful...!

Postby Peter_Frank » Sun Jul 05, 2020 7:21 am

This thread is about where you stand, feet position, the balance point of your hydrofoil, and not about how changing the design affects dynamics.

8) Peter

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Kamikuza
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Re: Shorter board is less playful...!

Postby Kamikuza » Sun Jul 05, 2020 11:26 am

Peter_Frank wrote:
Sun Jul 05, 2020 7:21 am
This thread is about where you stand, feet position, the balance point of your hydrofoil, and not about how changing the design affects dynamics.

8) Peter
Good, because that's not what I'm talking about :roll:

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Re: Shorter board is less playful...!

Postby salvino » Sun Jul 05, 2020 1:06 pm

Back to OP, I find smaller is so much more livelier with very little if any downside. On 633 Onda with 325 stab (forget this shim business or riding original stab) I have plenty of room for stance. Narrow or even wide, there is room. The only downside I see is my gibes need to be way more near perfect. Tacks are actually easier as board comes around so much easier. Sitting is even more fun.

I’m on pro macho Kanaha paired with 82 cm mast. It’s markedly more rigid than 91. Nice set up for normal luggage air travel, if I ever decide to ride an airplane again.....


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