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View Full Version : Different technique required for isonic 101 for speed compared to traditional shapes?


ned_321
30th April 2007, 04:19 PM
Hi all,

I have the iSonic 101 and 87 - for speedsurfing.

I have a problem in getting the 101 up to my "normal" speeds.
Performance on upwind and beam reach is good. But somehow I cannot find 6th gear on this board when going for a downwind speedrun.
MaxGPS so far only 62.x km/h, which is very disappointing.

Sails: Gun XS 6.2 and 7.4. Fins: Lessacher B+F 35 and 38. Mastfoot: 132-133.


Now all tests and sailing reports state that the larger iSonics (101 and up) run very flat with the nose very low. Sailing characteristic is different from more traditional shapes (such as the 87).

Does this different sailing characteristic (flat, low nose) require a change of technique?
Upwind and beam reach speed is not problem. But where it counts - downwind speedruns - I have lost speed compared to my "peer group".

Marko
30th April 2007, 05:26 PM
I am not so much into speed, more slalom racing but I found that this board is very different to former Sonic100/95.

I used the board only 3 times now (in very flat water) and I think that the key to good speed is to put very much downhaul in your sail. Then, the board will just fly on the fin with very light and slippery feeling. Everything will feel balanced. With not enough downhaul, board will be stuck to the water and you will have too much back foot pressure. My ex Sonic100 was much more tolerant to different sail trim but, on the other hand, is101 goes MUCH better thru lulls. It goes so good thru lulls that I also noticed I do not use adjustable outhaul so much any more.

By the way, my trim with 7.0 is everything in the middle with 36cm fin (deboichet sl2).

ned_321
30th April 2007, 06:21 PM
Hi Marko,

Thanks for the quick reply.
I already apply lots of downhaul in my sails. Most speedies (including me) use more downhaul than prescribed (and a bit less outhaul). In my case +3 cm.

The board already runs free. On beam reach the speed is good. But on downwind, the board does not get into 6th gear. It goes faster than beam reach, but only a little bit. Not the ferocious acceleration I'm used to when you turn downwind from beam reach.

ned_321
30th April 2007, 06:35 PM
Additional trim info: back and front strap both all the way back. Also tried back holes 1 to front, but then the board was less free.
No tailwalks even in strong wind (measured 18-25 knots; gusts up to 28) with 7.4 sail.

ned_321
30th April 2007, 06:36 PM
Additional trim info: back and front strap both all the way back. Also tried back holes 1 to front, but then the board was less free.
No tailwalks even in strong wind (measured 18-25 knots; gusts up to 28) with 7.4 sail.

ned_321
30th April 2007, 07:40 PM
By the way: how much tailkick is the IS 101 supposed to have?
My measurements (with metal ruler over finbox):
-absolutely flat until 1 cm from tail
-then 1 mm tailkick over last 1 cm (progressive curve)

Doby
30th April 2007, 08:00 PM
I asked the same question about my 115 about a year ago, Ian Fox laughed at me....

ned_321
5th May 2007, 09:54 PM
I hope Doby is not right, and that Ian is just away from internet access.

In the meantime, I have gotten reaction on the windsurfing33 forum. Advise was to put the mastfoot at 129-130. This is about as far back in the box as you can go. But I'm going to try it anyhow.

Here are 3 photos: 1 of the fin I use; and another of the mastfoot in 133 (current) and 130 cm (next time).

Lessacher B+F 35
<a href="http://photobucket.com" target="_blank"><img src="http://img.photobucket.com/albums/v642/NED_321/LessacherBF_35_DSC00002.jpg" border="0" alt="Photo Sharing and Video Hosting at Photobucket"></a>
http://img.photobucket.com/albums/v642/NED_321/LessacherBF_35_DSC00002.jpg

Mastfoot at 133
<a href="http://photobucket.com" target="_blank"><img src="http://img.photobucket.com/albums/v642/NED_321/iSonic_101_mastfoot_133.jpg" border="0" alt="Photo Sharing and Video Hosting at Photobucket"></a>
http://img.photobucket.com/albums/v642/NED_321/iSonic_101_mastfoot_133.jpg

Mastfoot at 130
<a href="http://photobucket.com" target="_blank"><img src="http://img.photobucket.com/albums/v642/NED_321/iSonic_101_mastfoot_130.jpg" border="0" alt="Photo Sharing and Video Hosting at Photobucket"></a>
http://img.photobucket.com/albums/v642/NED_321/iSonic_101_mastfoot_130.jpg

ned_321
5th May 2007, 09:57 PM
Another try at putting photos in.

Lessacher B+F 35
http://img.photobucket.com/albums/v642/NED_321/LessacherBF_35_DSC00002.jpg

Mastfoot at 133
http://img.photobucket.com/albums/v642/NED_321/iSonic_101_mastfoot_133.jpg

Mastfoot at 130
http://img.photobucket.com/albums/v642/NED_321/iSonic_101_mastfoot_130.jpg

Ronny
11th May 2007, 10:17 PM
I would advise you use a 32cm fin if you want speed downwind .

Marko
15th May 2007, 01:14 AM
I spent some more time on is101 and found some things that made me faster.
I raised my boom quite a bit comparing to my old sonic and I set my footstraps really tight so my feet are very much at the edge of the board. I also played a little bit with mast base and found that it is faster when back. It was really choppy so I had it in the middle position, but I think that in flat water and downwind runs it could be really good if placed back.

I also found that I had to adjust my stance with isonic compared to sonic. I am much more far out from the board and a little lower, similar to highwind formula sailing so I am also thinking about longer harness lines also.

By the way, what is your best speed on is101?

ned_321
4th June 2007, 04:46 PM
Best speed so far 63.3 kmh (2 second) with 7.4 sail.
On it&#39;s predecessor (SX 106) I got a GPSmax of 68.4 with a 6.2 sail, and multiple 65+ on 7.4 sail. So still missing at least 3 kmh.

On the IS87 however, things are getting back to normal. Clocked 72.7 during last USM.

ThierryP
5th June 2007, 03:48 AM
Ned_321, Ronny is right, 35 is much too big on a 6.2 for speed. I have sailed my 06 105 with a 6.6 TR-1 using a 28 cm Tectonics Goldwing fin, with very few spinouts, and I am not such a good sailor. You can surely go much smaller than 35 on your 6.2.
Anyway, I do not think that all-out downwind speed is these boards&#39; strong point, it is rather their speed on all points of sail, especially upwind and on a beam reach, and ease of use.
Let us know your speed after you&#39;ve dropped fin size.

ned_321
5th June 2007, 04:17 PM
Hi Thierry,

Until now, I only used the 7.4 sail on the iS101. Hence the 35 fin.

Will try a shorter fin (30 or 32) once I get to use the 6.2 sail.
Spinout is not the problem. But with a too short fin you don&#39;t get enough lift; then the board does not run free and high.

I know from experience that a small fin is key to speedsurfing. But there is a limit to how small you can go. Once you&#39;re under-finned, you go slower instead of faster.