hardie said...

Geez I've got 4 boards with Cutouts but no chick has shown interest in me? Maybe its because I'm an old fat ugly bastard

just caught your reply..maybe start cutting away and trimming should do the trick no theories needed

Mrgob said...

I would have thought the hydroplane idea would suit windsurfing. We're small light and fast already, so if reducing drag and wetted surface is important (for greater speed) why doesn't it work? Does it cause too many control problems?

I don't mean just those crazy fins that lift the board out of the water.They seem to have disappeared. I mean a properly designed board that blasts along on stilts.

Too much drag with current fin shapes as the fin needs to provide lift as well. A speed board has a very small contact area already. Mal did discuss that future fin shapes may change this problem, but most of it just fried my brain. Too much maths

I have used cutouts on a very small speed board which improved its trim and performance by 4 kts but by adding them you may increase the drag by having a longer trailing edge. You don,t get something for nothing

evlPanda said...

mr love said...
I have done 38 knots on this 69cm wide board with a 37 CM McDougall/Lockwood slalom fin in it and know I can get it over 40 in the right conditions with a more sweptback fin and after eating 10 pies, so I don't think there is anything wrong with the theory.

****!

Ask Bender what he's gotten out of an F2 SX XL (80cm wide) with a weed fin

Bender, Thats bloody quick for a big board.

My board felt really composed at 37-38 at which point the fin started generating too much lift. It actually turned me into the bank at 38 knots which was a bit scary.

If I had a smaller fin or a swept back it,s defnitely capable of 40knots at the PiT. I have tried a really small fin in it and it just got way too Skatey.

Besides the obvious reduction in wetted area I am pretty sure what the cutouts do to a wide tailed board is allow the nose to trim a bit higher and really unstick the board. You can fly it off the tail just as you say and it reduces the wetted area alot.
The plates than you can fit to F2 boards demonstrate this well. When you are overpowered in choppy conditions you fit the plates which partially fill the cutouts and they trim the nose down and help control.

Obelix said...

Bender said...

The board has really deep cutouts. i think this really helps with top end control as to get it really fired up i had it flying right off the tail (mainly on the narrow middle bit between the cutouts).

When you say "deep" you mean like the 2 bottom boards of the photo above?

Yes i'm pretty sure the F2's are at least 25mm deep without the blanking plates in.