Thursday, 17 March 2011

Select S10 Vs S11 - Preview


My new Select S10 & S11 fins arrived the other day and I am waiting for some wind to put them through their paces.  The S11 is promoted as a more powerful and upwind orientated fin when compared to the S10.  It is my inderstanding that the smaller S11's(Slam 25-39) are very similar in shape to the S07 and the Larger S11's (Race 41-61) are a completely new shape.  The chord mid-line rake of the S10 & 11 are very similar and since the S11 has a larger area in the tip the leading edge is slightly more vertical.

The fins pictured are a 37cm S10 and 41cm S11. 

The most noticeable differences in the plan view is obviously the tip area but when you look at the thickness the S11 is MUCH thicker in the tip.  I will get the verniers out when I get the chance and compare the thickness ratios down each fin.  Looking at the fin selector charts it looks like you can use a size smaller in S11 compared to S10 for the same drive amount of drive.  It will be interesting to see how the different sizes compare across and downwind.

Similar mid-chord rake.

Tip area - S10 front, S11 back.

 Tip thickness - S10 top, S11 bottom.

I took a few measurements of the fins at the base and tip(before the sweep on the leading edge).  

S10
Base - Chord 103.7 - Thickness 9.8 - Thickness/Chord 9.5%
Tip - Chord 53.6 - Thickness 5.3 - Thickness/Chord 9.9%

S11
Base - Chord 108.4 - Thickness 9.3 - Thickness/Chord 8.6%
Tip - Chord 61.3 - Thickness 6.9 - Thickness/Chord 11.3%!!!

So both fins have a Thickness/Cord ratio that increases towards the tip but the S11increases by 2.7% compared to the S10's 0.4%!.  This gives me the impression the fin will generate more lift from increased flex at the base and blocked twist at the tip with the thicker section.

3 comments:

  1. I have used the s11 37cm a couple of times. Much better than my Drake42! Great with a 7.7 full cammed sail.

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  2. Hi Lea, Good to hear you liked the S11. What board do you use it on? Did the 37 have the same power as the Drake 42? The tip is really thick!
    Tim.

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  3. Hard to say at the moment, the wind died off really quickly on both sessions. I only started a couple of years ago so like many was overfinned for a while. Used to use my 7.8north xtype with the 42drake, and when I tried with a drake 36 free slalom swift (comes with the Kode 112l) the board would not free itself from the water at all. With the 37cm it was planing as quickly as the 42cm, and upwind I reckon I only lost maybe 5m over a half mile that the extra length of the 42 would have given. Speed was a lot better though with the select. I am going to get a 31 soon, and a 27 hopefully. I like them!

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