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-   -   fin spin (http://www.star-board-windsurfing.com/forum/showthread.php?t=15452)

Unregistered 2nd June 2012 02:01 PM

fin spin
 
hi, i have a starboard futura technora 155, 8.5 ezzy sail, drake r13 race 520 nr fin, 175 lbs, advanced intermediate sailor, inland lake sailing in michigan 15-25 mph winds. i am spinning out my fin while planing, footstraps are all the way out. this has been happening more & more frequently - do i need a bigger fin? or a better foil shape? any specific fin recommendations would be greatly appreciated.

Jille 2nd June 2012 09:18 PM

Spin out at high speed speed or low speed?
My experience with large fins is spinning out because of to little speed/to much vin pressure.

I tend to keep pushing with my back foot at the side of the board, even when the wind (and speed!) drops.

Roger 3rd June 2012 02:23 AM

Jille brings up a very good point.
Often, when a fin let's go (spins out due to over pressure cavitation) it very often is
due to either diminishing wind, change in wind direction, or change in board speed.
A fin can withstand only so much pressure at any give water speed past it.
So. if the speed drops, but the pressure does not, it spins out.
If the wind drops, often we fall back a bit as we are not longer supported as well
but the harness and rig. This results in us putting more pressure on the fin, at a time
when board speed is diminishing. So the fin spins out.
Overall, it could be a technique issue or it could be a fin size/quality issue.
Have you wet sanded this fin to remove the logos and painted on printing?
Is the leading or trailing edge damaged.
You can try a larger fin but on the Futura 155 with an 8.5 m2 rig (in 25 mph/21.7 knots ???) I would think you would want to use a smaller sail and perhaps a smaller fin.
Are you sure that your board is not "tail walking" rather than spinning out?
Roger

Ken 4th June 2012 06:58 PM

All things said are worth checking. However, Roger probably can't say much about the Drake fins. I received two with my 2008 iSonic 111 (a 38 and 44). Both would spin out all the time with little back foot pressure. I also sanded them with no success. I bought a Tectonics Tomcat 42 and presto - no spin out. I can and have pushed it hard enough to spin it out, but if I do, it comes back in line with ease. Not so with the Drakes.

Jille 4th June 2012 08:06 PM

I like the gray slalom Drakes a lot, but had some spin out experiences with the red slalom ones.
Don't know what the exact problem is, the red ones seem to be a bit thinner and (because of that?) a bit more sensitive for spin outs.

Maybe the topic starter can give a some more info/feedback on the info so far?

Ken 5th June 2012 04:10 PM

I believe the red fins that came with the iSonics were ALL bad. There was much dialogue at the time (2008-2010 more or less) about the fin problems. Now Starboard doesn't provide fins with the iSonics since everyone was buying custom fins to go with the boards.

James 6th June 2012 11:44 PM

Have you ruled out increasing amounts of weeds in the water as the reason for the fin spinning out more often now than before? It only takes one or two little bits of weed stuck to the fin to make it cavitate and spin out. Sometimes the weeds aren't obvious.

Lessacher 21st June 2012 10:58 AM

The best way is,to work fins without spin out. When I say, please use a 40cm Rake 30° fin, doubleassym.
fin in 100% carbon. The most reaction is,,to short.She is 50cm long. On a weekend, 3weeks ago, in Netherland. Edwin Hartsveld tried to make a record for Formulas.A PD Board,2fins from Select and Drake.
He made 56km/h,but it should be 65km/h. I said please try a fin from me. He looked, to short was the answer.He took the fin, Sail 10m˛. 2 hours later. He made a new topspeed record. The 22cm made with Thomas Döblin made topspeed 50 knots. Andre Daff made in Australia on lake with 22cm >Rake 30°
a one hour GPS rekord,He was faster than the dutch boys.At the moment is J.van der Hout a little faster.
Last week wrote the dutch,a new GPS record 10sec. with 48,59 knots. But Thomas Döblin made
48,66knots. Rake 30° can weed, if you are fast. And sorry,it is always the fin who make a spin out ,not
the board and not the man. And if that could be, than have I so long to work that a fin cannot make a
spin out.I worked alone 30 years with doubleassym. fins. I found 35 points,what a surfer can do to make
spin outs,in flat water,waves,chop,sweet water,saltwater,low wind, high wind and so on.And be sure,
I want only that people must not write what a spin out is. I saw all it under a board with acryl bottum.Only
there see you live all that what can be. Wolfgang

Unregistered 21st June 2012 11:44 AM

Everybody spins out some time or other.. Suspect its normally overoading fin before sufficient speed has been reached; a larger fin will provide more lift at lower speeds and could appear to alleviate the problem but the larger fin will bring other related problems (too much lift higher speeds/tail walk/less control are all possibilities)

Try a larger fin but I think wearing a GPS really helps;it may well help but you might well be travelling slower. Smaller/correct size fins (for allround play) do require a bit of technique to get best. Bare away initially until good speed has been attained and then head up to required angle; only loading fin up at speed) This is best way tget V max but possibly not best Vmg.. (Big fins are king of VMG)

PS Fins DO NOT CAVITATE. They airate..Completely different process.. Cavitation requires such low pressures that water boils/evaporates at certain spots.This produces pitting on stainless steel race props. (and submarine props) I`ve yet to witness any WS fins with cavitation damage ..Ws fins suck air down from surface and which produces loss of force;hence spin out..

Experiment but be objective. Find a fin that feels good but check its not inhibiting you in other areas.
Its all a compromise.

Lessacher 21st June 2012 03:41 PM

You write: Fins do not cavitate, they airate.... Where is the begin of spin out? At the nose or at the end.? Wolfgang


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