4

Rake

Boogie fins
I am a bit surprised that I never wrote a article about rake & speedsurfing... So here it is:

Rake is a measurement how much the leading edge of the fin is leaning backwards. Speedsurfing fins are found in different rake inbetween 10 degrees till 30 degrees. In general you can say longer fins have less rake, shorter speedfins have more rake.

In the Netherlands speedsurfing scene Rake became a hot item after Martin van Meurs and Boogie developed the C3 X1 and X2 series. Extreme fast profiles, but required a lot of rake. (fin on picture is a c3 X2 24cm 30 degrees rake)








Why would you need more rake??? There are 2 simple reasons:

  1. More Rake= less taillift = more control
  2. De-twist problems, some fins twist the wrong way, by adding more a lot rake the twist turns the right way.

And some difficult reasons:

  • More rake is according to this graph allowing more AOA (graph found on Boogie his site). This means underneath a v-bottom a raked fin allow the board to generate more lift....?!? Still I haven't really experienced this fact... I have experienced the tectonics falcon f1 design allowing more AOA...graph angle of attack versus rake

















OK, nice to know this theory but what about us?? What would a normal speedsurfer need?

To all speedsurfers: if you buy a select fin it is possible to order a specific raked fin, this is what I do all the time. Some standard select fins have a bit to less rake for amateurs that are going for high speeds.

For most speedsurfers these rake work the best:

  • 21cm=20 degrees
  • 23cm=20 degrees
  • 25cm=17 degrees
  • 27cm=15 degrees
  • 29cm=15 degrees
  • 31cm=13 degrees
  • 33cm=13 degrees

If you would use less rake the fin will produce more taillift and the ride feels more scary (I think the board will pop-out feeling). That is why I recommend most surfers to use some rake. Because control=speed.

Eriksurf

Erik is windsurfer for 10+ years. In his daily life he is professional in construction dewatering, advisor, troubleshooter. Erik likes adventures, explore and to challenge himself. During his life he is trying to get the best out of it and have respect for the earth, nature and future generations. The modern world is about sharing, in this blog Erik shares his experiences, selfreflection and lessons learned.

4 comments:

  1. MarkFebruary 27, 2009

    Is this also true: more rake = flatter ride.

    Board with a lot of lift (i.e. Fanatic Falcon concave) need more rake?

    I noticed a flatter ride with my C3 Venom instead of a Select SL7 with the Falcons 2007/2008.

    ReplyDelete
  2. EriksurfFebruary 27, 2009

    Hi Mark,

    I really can imagen the C3 fins give a flatter ride. But more rake does not give a flatter ride.

    The new C3 fins (and many other fins) have more flex than the Select SL7 series. Flex gives extra taillift (taillift is the back of the board comes out of the water), and extra taillift does give a flatter ride.

    But most speedsurfers (including me) can't handle a lot of tail-lift so we use more rake or shorter fins.

    I have only felt 2 times the C3 fins, didn't sail them. But Boogie did the same trick with his design Venom. The design just got to much taillift if you would sail it with the same rake as a select. So Boogie has to use 3-5 degrees more rake for the same range.

    But the fins will always have less power compared to the select fins.

    Cheers,

    Erik

    ReplyDelete
  3. AnonymousMarch 09, 2009

    erik

    the c3s may have less power for a given size, but the great thing about these fins is that you can use a bigger size without compromising speed. in fact, the best thing about these fins is that they give power at low speed (when you need it) and less at high speed (when you don't). that's imho (and compared to the select fins I tried in the past) the biggest difference & advantage of the venoms.

    also, I'm not sure about what you state about the flex, but the venoms definitely have more twist, due to their thin profile/narrow outline towards the tip.

    my feeling is that the main advantage of the additional rake lies in the increased control at high speed. there is no saturation, just acceleration.

    grts

    chris_bel29

    ReplyDelete
  4. EriksurfMarch 09, 2009

    Chris,

    Of course additional rake gives control in some cases (actualy most cases). That is why I advice in this article for high speed surfing most windsurfers will benefit a bit more rake than usual.

    For the CA Slalom 62 I changed the SL7 33cm rake from 11.5 degrees to 13 degrees. And this was giving a bit more comftable ride.

    Cheers,

    Erik

    ReplyDelete