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2nd March 2007 07:59 PM
RE: isonic 111 - trouble with back foot


How high is the boom with those sails? When upright, does it come above chest high?

If not then go to a good sail maker seek advice. He may be able to adjust the sail to suit your height. You could also change brand of sails. I know a couple of tall guys who have similar problems on some sails.

As I'm sure you realise, moving the mast base back effectively raises the boom reducing back foot pressure.

Sail tuning can also have a big effect on back foot pressure. If your harness lines are too far forward you will be pulling in the sail with your back hand, this in turn transfers sideways pressure to your back foot. Too little downhaul/outhaul can have the same effect.

The easiest thing for you (and to get some correct advice) would be to post on the windsurfing school forum. The above advice I got from Roger and as usual, he was right. It might be worth you posting a picture of you sailing with the sail and one of you standing holding the rigged sail. I'm sure that would really assist with any diagnosis.

You can easilly upload pics to http://www.windsurf.me.uk/cpg133/ then attach them to your post on this forum.
2nd March 2007 07:07 PM
RE: isonic 111 - trouble with back foot

Yes, do as CarlosD says. I had the same problem with Hypersonic, Much backfootpressure and the "fronfoot feels like flying out of the strap.
TO do:
1 Lower the boom
2 More downhaul
3 The mast a bit more forewards
4 Frontfootstrap a bit more backwards if possible
5 ligth Flexion of the knee in the back leg
6 Extended frontleg

With regards,
2nd March 2007 01:07 PM
RE: isonic 111 - trouble with back foot

Poor guy. Our answers are pointing to different directions, and I guess are adding confusion to confusion.
Matt is such a big guy that probably the 111 + 7.8 combo is a 20 knots + setup for him. This could partly explain the use of smallish fins on such a big board. Nevertheless, at 200 cm and 100 kg, leverage power is such that it must be very easy to push too hard on the fin, expecially if one is seeking balance to sail railed.
Probably sailing style and stance are not to be overlooked. My guess is that the 111 (which I don't own or ride) could prefer to be sailed level, instead of railed. Maybe this does not show up in lighter winds but could be an instance at higher speeds (7.8). I do also think that with the mast forward one gets too much leverage which could be difficult to manage, while mast back requires more attention sheeting in but also does not lean towards excessive push on the fin.

Maybe someone who knows could make suggestions about the 111 character, if it is supposed to be sailed railed or flat. But beware: 2 meters tall + 100kg+ fast materials + correct stance + good setup... ind the end we could be generating a monster...
2nd March 2007 09:58 AM
RE: isonic 111 - trouble with back foot

Too much backfoot pressure? Sounds like you already have the boom high. Have you tried moving the universal to nearer the front of the mast track??
2nd March 2007 09:37 AM
RE: isonic 111 - trouble with back foot

Just to get a proper perspective on things, I think that one needs to decide whether they are trying to handle the biggest sail in heavier winds (for high speeds), or using a bigger sail to get the most out of the lightest of winds. Although there may not be that much difference in the size of the sail used, the size of the fin can be quite a bit different.

I'm not a big or heavy person, but for a number of years I was successfully using a 50cm Tectonics Mirage on an older course slalom (284cm x 61cm x 115 liter) with an 8.1-8.3 sail in light winds (12-18mph average) with no problem. Really, I don't find it surprising that bigger heavyweight guys using 36-38cm fins on 7.8-8.4 sails might find that they have real no low end and struggle with spinouts.

If one still wants to keep fin size small for a fairly broad range, I would recommend checking out Wolfgang Lessacher's 100% carbon asymmetricals. His smaller fins have this incredible resistance to spinout, particularly his weedfins. I can't really explain it, but tracking ability of his fins are simply amazing, especially pushing hard to windward.

2nd March 2007 08:49 AM
RE: isonic 111 - trouble with back foot

Hi Matt,

I agree with Geo that probably you are using very small fins for your height/weight. I´m sailing my new IS111 mainly with a Code Red 7.7 and I found that the 36 cm fin is okay while sailing well powered (+ 14 knots) I am weighing 89 KG. (1,85 tall)
Since your weight is around 100 KG you would need more fin surface in order to obtain enough lift. (38/40 for the 7.8)
As you are using the boom in the highest position you are obtaining a high proportion of the lift throught the vertical component of force produced by the sail (wich is probablly too much leaned windward) this means that you are losing forward performance.
I guess that if you try to use the boom in a lower position, with long harness lines and a bigger fin your sailing performance will improve, not only with the 7.8 but with all your sails.
then you can trimm the straps and the mastfoot positions.
Here you can see the opinion of kevin Pritchard as regards boom height and harness lines (he is a tall guy too)



I hope this will help you, sorry for mi poor english :|.

Best Regards

2nd March 2007 03:10 AM
RE: isonic 111 - trouble with back foot

Perhaps the best solution would be to change sails. Such shortcomings are intolerable for dedicated racing materials.
2nd March 2007 02:14 AM
RE: isonic 111 - trouble with back foot

i've been having lots of problems as well - i'm 197cm tall and using a 161, 122 and 101 and i've struggled all year (also with with RS6's). on the 161 with the 10.7 i cut the neoprene boom cut out faring to get the boom up - i've resisted cutting the 7.8 but i am rigging it with the mast base 2-4cm higher specified which leaves the sail sitting a bit high but gives me that extra bit of boom height

not ideal and i'm also still experimenting

i'm thinking theres discrimination against tall people this year!

1st March 2007 08:36 PM
RE: isonic 111 - trouble with back foot

I guess you are using small fins for that board and sail combo. Personally I (6'3"; 185) used a 34 Deboichet on a Sonic 95 with 7.6 and found it smallish; it will mate to a 7.0 for next season.
Of course, if your sail cutout is too low, setting the mast track all the way back could ease things a bit resulting in an higher boom position when sailing.
1st March 2007 06:59 PM
RE: isonic 111 - trouble with back foot

.... I forget to mention that I do not have any trouble with my 133 and the 9.0 - 9.8 sails

thxs again
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