View Full Version : ISonic fine tuning (For Ian and Kevin)

6th February 2007, 12:37 AM
Hi Kevin and Ian ,

Next week I will receive my long awaited new slalom boards (ISonic 87 and 111)

I would like to know (from your point of view) if both boards cover the whole 10/40 knots range for my weight and height with reasonable overlapping , and the recommended mastfoot and straps positions in order to achieve maximum performance.
Also I would like to know about optimal fin sizes and brand for my different sails-boards conmbinations.
I sail in both flat and choppy conditions.

Weight 89 kg (excellent pumping and speedsurfing skills)
Height 1,84m

Sails: Code Red 7.7
Code Red 6.7
NP RS6 5.4

Next sail Code red 9.0

Carlos Duperron
Buenos Aires

6th February 2007, 05:16 PM
Hi CarlosD,

I have the same pair of boards as you (ish, I have the 115, not the new 111) and hopefully this will be great. The 115 works really well with my 8.5 Tush Lightning and even better with the 7.8 Lightning. I have also used it to good effect with a 6.5 but now I have an 87 I would switch to that if it's good 6.5 weather.

At the light end the 115 does take a bit of effort to get going but onece up will stay there easilly. I have used it in nuking winds (before the 87 arrived) and it coped well on the flat but the chop was a problem.

Unfortunately, there has been no wind here since the 87 arrived but the forecast looks good for the coming weekend, bloody cold though.

Take a look at this thread Ian wrote in response to my similar questions.


6th February 2007, 07:15 PM
Hi Phill.

Thaks for the link
I can see your weight is similar to mine, so we should arrive to similar conclusions, I hope next weekend (our forecast looks good too) we will be able to play with the new toys and then we can share our experiences.

Best regards


Ian Fox
7th February 2007, 03:48 PM
Hi Carlos,

To add to the comments at the link shown by Phill above, in your weight/sails/conditions the iS111 will be marginal up until around 12 kts (in reality it depends on the quality of the wind and the flatness of water, plus rider skill/energy to get the very bottom of the planing threshold, and with 7.7 you are "OK" but would benefit from more sail size to really get the best chance at a real 10 kts.

Top end, yes, but again it will be marginal and mostly determined by the solidness of the 40 kts, and the water state (flat offshore or rough onshore both in 40kts are totally different situations. In general I would suggest the iS87 is really a bit much board for true 40 kts in anything except very flat speed trial conditions, and even then because actual board speeds will be so high, a smalle rboard would mostly be ideal. Think about the practical top end range being mor elike 30-35 true knots.

Either way, you'll have fun. Let us know how it goes !
You too, Phill !

Cheers ~ Ian

8th February 2007, 10:01 AM
Hi Ian,

Thanks a lot for your comments,
Of course I assume that the real range for the IS87/111 quiver is from 12 to 30/35 knots in order to race with the best possibilities with my 89 kg. and my actual sails set
The more specific questions shoud be:

1-May I expect to begin planning at 10 knots with the new Code red 9.0 that I??m just ordering ? (assuming a good pumping ability)

2-Is there enough board overlapping In the middle of the range (18-25 knots ) ?

3- A 4.6 slalom sail would help to sail safely (I??m not talking about reaching ideal top speed, just surviving) on the 40 knots wind range?

As soon as I can sail the boards I will tell you the first impressions (I hope next week):D

Best regards


Ian Fox
8th February 2007, 11:46 AM
Hi Carlos,

Q1 = May I expect to begin planning at 10 knots with the new Code red 9.0 that I'm just ordering ? (assuming a good pumping ability)A1 = Yes, the extra sail size (over) your existing 7.7m will force the most practical early planing out of the iS111.

Q2= Is there enough board overlapping In the middle of the range (18-25 knots ) ?
A2 = Just enough to be practical, but not too much extra ! You will find 6.7m is still good on iS111, but really the CR 7.7m has a bit too much power for general sailing on iS87.

Q3 = A 4.6 slalom sail would help to sail safely (I'm not talking about reaching ideal top speed, just surviving) on the 40 knots wind range?
A3 = Yes, for survival it will help for sure - and if the water is flat you will reach some crazy fast speeds in that combo, even though 4.6m is smaller than normal for that board/89kg combo. This one again depends on how "solid" the wind is at 40kts - if it's gusty offshore 40kts, (so 25-30 gusting 40) then likely the 5.6m is actually a more stable (if overpowered) power, if it's really solid 40 - then 4.6m+smaller fin (26-28cm) ..and hang on !!:o

Cheers ~ Ian

9th February 2007, 04:08 PM
Given the current weather here in the UK it may be some time before I get to try the 87:(


mark h
9th February 2007, 09:20 PM
Hey Phill
I dont mean to teach my granny to suck eggs, but I think the boom might be to high for Mr Snowman, especially when considering that he appears to have any very short arms:D


9th February 2007, 09:57 PM

Mr Snowman has his boom quite low compared to me;)

Ian Fox
10th February 2007, 05:20 AM
And that "87" has also put on a bit of weight over winter.. ;)

10th February 2007, 09:06 AM
To Ian:

Thanks a lot for your detailed answers, I will keep you posted as soon as I can try the new machines (they arrived to Buenos Aires but some custom papers must be done before I get them (the waiting is killing me!!!!!),

To Phill

Don???t give up Phill !!! 5 minutes on the IS87 well maybe worth one week bed ridden, but??? thinking it better, not even the snowman seems to be happy while sailing (look at his face!)
At least you have your board; I have my new babies jailed in a container at the port. Meanwhile the wind is blowing every day.



12th February 2007, 02:13 AM
Today I finally got to try the iS87 and I'm very impressed.

The board is very well finished (much better than my iS115 that had some obvious scratches touched up from new). It comes with the race straps which I had to fit in the largest setting and using the widest insert holes. I'm a size nine (UK) and it's obvious that these straps are meant to be used with bare feet. Unfortunately it's bloody cold here at the moment so I had to wear my booties. I think it would be a struggle to use these straps if you have feet bigger than mine and want to wear booties.

I rigged the board with a 6.4 Tush X15. Luckily there was a guinea pig on the same kit out (Cheers Duncan) so I knew this was right. Being my first go I was a little tense and sailed like a Muppet for the first few runs. I soon got the hang of it though and was amazed by how easy this board is to sail.

The volume is well placed under the feet giving a really comfortable shape to the board. Getting the board planing was no effort at all and it accelerates so quickly. Once going the board is so well mannered and just goes where you want it making steering through the little bit of chop there was very easy.

The supplied 32cm fin is very powerful and was too much for the 6.4. It's probably more suited to a 7.0. I should have come in and swapped fins but I was having too much fun.

I didn't really push the board to it's limit partly due to the fin but mainly due to the angle of the wind. I still managed 30.1kts and there was loads more to go. Had the wind been stronger and from a better direction I'm sure it would go much faster.

One of the most impressive aspects of this board was it's ability to gybe. I was a little worried about turning it but I am pleased to say it was easy. I actually managed to come out of a gybe planing, a rarity for me. I even found it quite easy to tack considering the lack of volume in front of the mast.


You are going to love this board:D

I've attached a pic of someone else sailing today just to show the conditions in Portland Harbour. He was on a Kombat 96


12th February 2007, 10:55 PM
Could someone please tell me if the Isonic 87 has any sidecuts or cutouts at the rear.



Ian Fox
13th February 2007, 08:43 AM
iS87 has vertical side cuts at the tail ~ but no cutouts (underneath).

Cheers ~ Ian

13th February 2007, 09:32 AM
I lie if I say that i??m not a little envious beacuse of your IS87 first flight (mine is already in the container :( waiting that our customs bureaucracy finish the papers, I hope tomorrow I will receive it).
It??s nice to hear that the board have a nice jibing ability because exiting jibes planning is not my speciality and surely the new board will help me a lot.
Meanwhile I??m sailing my JP Slalom II 114 (the last runs, because It will be replaced by the IS111) and trying a friend??s IS105 (amazing!lots of speed and control, I hope the IS111 will be already better)

good winds, I will keep you posted


13th February 2007, 10:49 PM
Thanks for the information Ian.



14th February 2007, 03:50 PM
Thanks for al the information so far guys, since I'll have my 87 to cover up the highend situations of my 111, I'm wondering what downhaul/outhaul/boom/mastfoot-settings you would suggest when surfing with:

CR 4.6 / 5.6 on iSonic 50
CR 5.6 / 6.7 on iSonic 87
CR 6.7 / 7.7 on iSonic 111

And finally I was wondering what sail size should be possible to put on top of the 7.7?

Ian Fox
15th February 2007, 10:03 AM
Hi Julian,

There a really are a lot of significant variables that will influence the "ideal" setings for downhaul/outhaul/boom/mastfoot (even on specific sail/board combo/s). Depending on the individual rider (height/weight/stance) plus personal settings like harness line length, fin selection (tuning and style), the water conditions (flat thru to extreme chop), wind (steady thru to super gusty) - and then the type of sailing (slalom racing [requires acceleration as well as speed] - pure downwind, or Fig 8 [with some upwind leg], hi wind reaching [blasting] or downwind pure speed GPSSS style [only concern for highest absolute speed, not upwind nor accel] ...and so on) the ideal settings will definetly vary.

In general, the CR responds best to medium to strong downhaul,but not to the point of totally killing the sail and indicing twitchy handling. Outhaul usually varies from moderate positive (beam recah or upwind) to moderate negative downwind/broad/speed or in some case quite negative for pure downwind speed)

Boom again, moderate high (average) - depending on many of those variables above - a little higher in "ideal" conditions and a little lower in totally crazy (control) conditions can help - although the higher position exerts more leverage over the rig in higher powered conditions, too.

Mastfoot placement is pretty easy, just bang it in the middle of the track (on those boards, with those sails ) and you won't be far wrong. Beyond that (again, really dependent upon many of those variables - and even fin choice in speed sailing can alter ideal stance, which in turn effects both mastfoot and boom height etc) - if you do need to move from centre, the general recipe is usually a little further FWD (2cm) in rougher or control conditions, and a little 1-2cm BACK for flatter water/higher speed.

Hope this all helps, well a little, anyway.

With some more detail specifics, it becomes a little more practical to offer (accurate) finer tuning tips - let us know !

For the bigger sail than 7.7m, typically the best size jump "up" would be the 9.0m in CR-R2. 8.3m actually works really well, and especially with the iS111 but is a fair amount of overlap with the effective range of the 7.7m in normal use. Considering the range of both the board and sail, if getting the most range from the next sail is the objective, then 9.0m is the upper practical limit (assumes less than heavyweight rider).

Cheers ~ Ian

23rd February 2007, 09:06 PM
Hi all,

Finally my new boards arrived and I managed to sail both in the last three days.

Day one

Offshore wind (very gusty and little to medium chopp) 12-25 knots.
First was the IS 111, I rigged my Code red 7.7 and the 36 cm fin The board was not only extremely fast but easy to control under these conditions (including the heavier gusts and bigger chopp when I became overpowered).

After 1 hour enjoying windsurfing at really high speeds I switched to the IS 87 , Code red 6.7 and the 32 cm fin, assuming that during the lightest gusts I would need an snorkel.
Not really ... taking off with the IS87 is very easy, and the board accelerates in an awesome manner, reaching high speeds in a pair of seconds. When plannig at such speeds the boards is able to cross large wind holes without problems and the jibes are very sweet.
Phill, you are right ,I love this board
When at full throttle the speed was terrific (seems to be a speed needle)
The 32 fin seems to be a little small for the 6.7 when pointing close to the wind, I will try a 34 on the next session.

I was very happy with the two boards (like a dog with two tails), unfortunately I dont have a GPS to measure speeds.

Day two

12/15 knots heavy chopp (0.70/0.80 cm)

Isonic 111, code red 7.7, 36 cm fin

The runs were almost upwind beacuse of the strong cross tidal current.
The 111 was flying again, this time over the big chopp. I measured 27.6 knots (vmax) with my new GPS (I could not wait more to have it)
Not bad for big chopp and square run.
The 36 cm fin is perfect for the 7.7

Day three

After 1 Hr session aboard a Gemini tandem (a hi-speed surreal experience, I will post later at the free forum) I rigged the IS 87 with the CodeRed 6.7 and the 34 cm fin.
The wind was stronger (20/22 knots), but when I finished rigging was only 15/18 and again the runs were upwind because of the cross current :@
Equipped with the 34 fin the IS87 points much better for my weight (89 KG) and despite the wind was too light for the quiver I measured 30.6 knots of Vmax . Another day of joy!!!!

I hope the next days I will be able to sail with better conditions, I will keep you posted

Best regards


24th February 2007, 02:19 AM

By any chance your day three was on past Wednesday 21 in the R??o de la Plata?
I think I recognize the conditions as I sailed that day and was caught by the same wind drop


24th February 2007, 02:40 AM

Glad to hear you enjoyed it. It's amazing how easy to sail the 87 is.

I find it interesting that you found the 32 fin too small and I found it slightly too big. Probably down to the strong tide you faced. I'm only a couple of kgs lighter.

Now you have a GPS I hope to see your tracks on http://www.gps-speedsurfing.com/gps.asp. It's really easy to post on there.

24th February 2007, 08:46 AM
Hi Luco,

Yes, you are right, I sail at the RDP from El Ombu (probably you know me as PIPO, my surname) Today the wind dropped again :@
If you want you can send me a message (in spanish of course) to cduperron@fibertel.com.ar

Hi Phill
How is the weaher like now there? I hope that the cold is diminishing
I´m just learning how to use my GPS, the Gartrip software and the excellent Realspeed soft (thanks Mal!) from Mal Wright, a really fast sailor and kind aussie.
As soon as our sailing conditions improves in order to obtain some decent results I will post them to GPS-Speedsurfing.
As regards the fin for the IS87 in general I use bigger fins than other sailors (for slalom, not for speed) I guess that my position (I apply a lot of lateral pressure on the fin) combined with the straps setting (rear position) are the reasons.
I will try a middle strap position with the 32 and then post the result , If possible I will measure speed with both settings (34 cm fin-rear strap position and 32 cm fin-middle strap position) for the 6.7 sail.

Best regards and good winds for all