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Cut outs on foil board ?

Created by normster normster  > 9 months ago, 17 Oct 2019
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normster
normster

NSW

346 posts

17 Oct 2019 1:54pm
Are cutouts on foil boards required ?

I was of the opinion that they reduce drag etc on a conventional board. bit i thought this was at higher speed.

Yet foiling seems to occur at a lower speed - further if cutouts were left in wouldn't that mean more area for earlier planing and then lift off ?

im a non foiler so excuse my ignorance if im missing something simple
Sail Repair WA
17 Oct 2019 11:30am
Hi Normster

Valid question,,

The cut outs helps on the early planing on bigger boards and also foil boards.

The board feel more 'free on the water' with the cut outs. The smaller the boards the less you need them.

Also with the cut outs you have better ability to 'pump the board up with your movements' , as with the less surface / cutouts (but still having the width), you can slightly change the 'trim angle' when you pump / accelerate more efficient and you don't have the whole surface (slightly draggy) to deal with

Hope my plain explanation make sense

Cheers
Jesper
DavidJohn
DavidJohn

VIC

17569 posts

17 Oct 2019 7:11pm
Select to expand quote
normster said..
Are cutouts on foil boards required ?




No
515
515

515

875 posts

17 Oct 2019 5:06pm
The cut outs are ate trade off from maximum width for leverage against a higher drag from total width vs narrower tail when with less drag to get on the foil
snides8
snides8

WA

1731 posts

17 Oct 2019 5:19pm
I have them on my jp150 but there basically there to make it easier to pick up
The board and stick in the trailer
LeeD
LeeD

3939 posts

18 Oct 2019 12:46am
As said...
Formula width tails need cutouts, unless you weigh more than 120 kgs.
60 cm boards with 38 cm tails do not need cutouts.
normster
normster

NSW

346 posts

18 Oct 2019 7:13am
Thanks to all for replies
Pacey
Pacey

WA

525 posts

18 Oct 2019 10:47am
I thought the cutouts were to reduce wetted area at high speed, if anything they increase drag at low speeds. For a foil board which is only in the water at low speeds, I really don't see why they bother.
LeeD
LeeD

3939 posts

18 Oct 2019 12:05pm
Smaller foils need more speed to lift.
Not everyone is using huge foils.
Pacey
Pacey

WA

525 posts

18 Oct 2019 1:23pm
Select to expand quote
LeeD said..
Smaller foils need more speed to lift.
Not everyone is using huge foils.


I am
berowne
berowne

NSW

1555 posts

18 Oct 2019 7:59pm
I find cut-outs under the mast impact zone are vital!




DWF
DWF

DWF

710 posts

18 Oct 2019 7:31pm
I don't like cutouts. They hurt early planing in my opinion.

I did some googling into tail cutouts and found one top race board with vent tubes drilled from the cutout inside corner to the deck. They were venting the suction/drag cutouts create when trying to plane.

Te Hau
Te Hau

495 posts

19 Oct 2019 8:31am
Fanatic don't think they're necessary and don't have them on their StingRay foil boards.
Easier to make without.
Cut outs on foilers could be the influence of the marketing man?
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