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pdbaker 17th September 2007 04:49 AM

weed fin for isonic 135
Just looking for advise for a weed fin for the isonic 135, 2006.
I'm 205 pounds, sail on inland lakes in the US, and will probably use the fin mostly with an 8.5 race sail.
- thanks in advance for any input.
Paul B

Roger 17th September 2007 09:15 PM

Hi Paul B,
There are a number of choices you could go with.
I depends a little on what type of weeds you need to have the fin shed, and how much weed there is overall.
The newer progressive rake weed fins work really well in light weed conditions with most types of weeds.
Examples of these new style "progressive rake" weed fins would be the True Ames Shallow Water Weed fins, and the Tangent Dynamics "Reaper" Weed fins.
The more swept back traditional (more than 45 deg. LE) weed fins will pretty much shed all weeds, but do't go upwind quite as well as the progressive rake fins.
Examples of this would be the True Ames Blade Weed, Gorge Fin Co. weed fins, and the
Lessacher Design Duo weed fins.
The Lessacher Design fins have the added "advantage"of being Asymmetrical which helps shake off weeds more quickly.
At your weight, I would suggest at least a 36 cm weed fin (they have a lot more area than normal vertical fins), but probably a weed fin in the 40-50 cm range would be better.
Hope this helps,

Lessacher 11th October 2007 01:16 PM

Hallo! The rake 45° Weedfins are diagonal longer, but how long?????? You remember?
1,414........... 24 cm is 34cm long
28 cm is 39cm long
32cm is 45cm long
36cm is 50cm long Wolfgang

Geoff 24th October 2007 09:47 AM

Are the stated length of weed fins the diagonal lentgh or depth the fin would be in the water? Do all manufacturers measure the same?


Roger 24th October 2007 09:21 PM

Hi Geoff,
The "stated length" is the depth below the bottom surface of your board.
As Wolfgang has described above the "diagonal length" is 1.414 x the depth of the fin
(for a 45 deg. Leading Edge angle).
This is the secant of 45 deg. (1.4142).
I believe that most fin producers classify their weed fins by the "stated length".
Hope this helps,

Geoff 25th October 2007 08:05 AM

Thanks Roger.
My next question is I notice there is some difference in recommendations in weed fin length, for example with a 6.5m sail wolfgang recommends a 28cm fin whereas other brands tend to sit at about the 32 to 34 cm range. If i'm correct there is a big area difference as well. At present I'm after a weed fin for an S Type 104 with a 6.6 sail with not to heavy sea grass type weed. I weigh 70kg, any recommendations from experience as I have never used one in the past but have got sick of trying to dodge the floating bands of weed I encounter.


Roger 25th October 2007 10:33 AM

Hi Geoff,
Unless you are really powered up and interested only in top speed, my experience with Wolfgang's Duo Weed fins (I have the 28/32/36/and 40 cm) suggests that you might be happier with the 32 cm as it works in a wider variety of conditions with both larger 7.8 m2 and smaller 5.6 m2 rigs).
Also, since you have very light weed conditions, consider one of the progressive rake weed fins from True Ames (the Shallow Water Weed 39) or Tangent Dynamics Reaper Weed fin (from Sailworld) in the 32 or 35 cm sizes.
The progressive rake fins have a little less area and go upwind very well, but tend to collect a few weeds if the weeds are heavy.
The Lessacher Duo concept uses concave/convex surfaces on the same foil to cause all weeds that land symmetrically on the leading edge (LE) of the fin to "flap" in the concaves and they slide right off.
If you ever come down to Hatteras, look me up and you can try all 3 and see what works for you.
Hope this helps,

Geoff 25th October 2007 12:11 PM

Yes that helps a lot, and thanks for the quick response. I would love to take advantage of your offer but America is a little far for the weekend, as I live in Australia, but one of these days you never know.

Thanking you

Roger 25th October 2007 08:49 PM

Hi Geoff,
Sorry, got you confused with "pdbaker" (who started this thread), aand he lives somewhere inland in the USA and sails on lakes.
Not sure what the weed fin options are down in Australia.
Lessacher Design, True Ames, and Tangent Dynamics can all ship worldwide, I think.

Lessacher 29th October 2007 08:17 PM

Hallo Geoff! The most of us use for 105l- 115l 24cm weedfins for 6,5m². 28cm for
115l-120l boards and sails to 7,6m². 24 and 28cm is vertical. Duo Weed or Chamäleon.
Joseph Presti is from Australia. Look: GPS....... ranking 216 or 81 Dieter Gerichhausen

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