View Full Version : iS 121 recommended sail sizes/wind range for 80kgs?

3rd July 2010, 01:58 AM
Hi Team,
Hi All,

on my iS 121 is a table stating recommended fin sizes for different sail sizes

Question: what wind ranges would you recommend for each sail to complete that table for a 80kg guy?

Hoping to hear something

3rd July 2010, 11:36 PM
Hi Duracell,

This grid should be good for you :

iSonic 121 : 7.5/Sl4 42 ; 8.6/R16 44 ; 9.0/R16 46

All the best

4th July 2010, 03:47 AM
Hi Remi, you didn't even address the question asked...

the question is which wind ranges go along with the table of fin sizes / sail sizes printed on the board for a 80 kgs guy...

mark h
4th July 2010, 07:53 AM
Only you can answer that one Duracell. People (regardless of weight) are comfy in different wind strengths, example: some can lock a 9m in 25k gusts no problem (fact), others can't/will not do that, and are comfy holding a 7.5m in 25k. Its an impossible question to answer as there is more than one way to cook a goose:)

5th July 2010, 12:53 AM
I don't live right next door to world class racers so I don't have the chance to just look and see what they use (and how). So, stupid as I am, I just ask, nor harm doing that or? I've made the experience that you learn some small thing almost every time out. Benefiting from other peoples experiences is what I was hoping for, so if you have something to share: spit it out (that is what this forum is about right?).

5th July 2010, 03:44 AM
Not from the team but from my experience..this is a very difficoult question and there are many aspects that are involved, and I kinda share mark's thinking..

I'm sailing iS 75cm for 3 years now and all that I can say is: in flat, little choppy water I (72kgs) like to sail 9 till 20 and 7.7 from 20 to maybe 26-7. I was on water beyond these limits with both sail sizes but it become a bit unconfortable. It also depends if you're freesailing or downwind or on the reach, etc..
With more chop this limits goes down but I can't really say: ehi with 17kt of wind and 50cm chop the best is XY because it's subjective and depends on where you're sailing/how you like to sail/which type of sails you have/which model etc..

Not much shortcuts here, except for the excellent fin-sail size chart that Remi gave you, just have to find your best combo..

5th July 2010, 08:41 PM

Good advice from Alex and Mark, and unfortunately, this one you will have to figure out for yourself through trial and error.

We all "scramble" when arriving at the beach and are trying to figure out what sail to rig. All of the below come into play including asking all your buddies what they are using and on what board.

Skill level of sailor
Body weight
Fitness level of the sailor
Board (weight, width, type)
Type of sailing (speed, slalom, longboard, formula, bump and jump, freestyle, wave)
Wind speed and direction
Wind forecast
Sunny or cloudy (clouds tend to kill the wind)
Water state (smooth, chop, waves, boat traffic)
Racing or freeriding
Limited time at the beach or the whole day (rig big if you only have a short time)
Goals (fun, top speed, racing, jibing/tacking practice, etc)
Point of sail (reaching or upwind and downwind)
Type of sail (RAF or cambered race sail)
Fin size
Water and air temperature (do you want to fall in or not?)

Choosing a sail size requires skill and experience to get it right, and even the most experienced get it wrong from time to time.

Make notes every time you come in from a sail. Eventually, you will build your own chart of what size to use.

It's all part of the windsurfing experience. Have fun.

7th July 2010, 01:48 AM
OK, rephrase question: what wind ranges would a world class slalom sailer use along with that table on flat or choppy water (<1m)?

mark h
7th July 2010, 02:21 AM
iSonic 121 for heavy PWA sailors.

7.5/Sl4 42 - 20k to 30k

8.6/R16 44 - 15k to 25k

9.0/R16 46 - 10k to 20k

Just guide only:)

8th July 2010, 02:49 AM
how does that translate for a 80 kg sailor for the following sails only?

8th July 2010, 11:23 PM

I weigh 76kg and use 6.6, 7.6 and 8.4 sails in my is 111. Based on your size and the iS121, I would estimate (ideal wind, not the possible range):

8.1 = 15-20 knots
8.6 = 12-18 knots
9.5 = 10-16 knots

You probably could plane in less wind than listed and could hang on in gusts above those listed. Since I am an older guy and a little smaller in weight, I personally would go about .5 to 1 meter smaller in the wind ranges I listed.

Hope this helps -

9th July 2010, 01:25 AM
thanks folks, it is nice being able to ask questions like this and getting some answers.
Windsurfing can be a quite lonely sport on the water.

I'm still quite impressed with my iS 121 WC, it handled my 9.5 sail + 47 fin with ease in winds gusting up to 20kts today in sometimes very choppy water (lots of boats). Top speed was an incredible 31.28 kts (2s GT-31) no wipe out.

9th July 2010, 08:37 PM

That's a lot of sail on a small board in a stiff breeze. Amazing speed in the rough water too. Impressive!

10th July 2010, 12:23 AM
hy Duracell,
can you send me gps track ? insandout2000@yahoo.it
what sail do you speak? RSR evo2?

12th July 2010, 01:32 AM
sail was an old gun Booster 9.5 with a LOT of downhaul, breaking all the way down till under the boom. Fin: select pro slam (PS) 47.
whish I could send gps data, but word of warning, a day later I lost the thing, it fell out of the armstrap "optimized" for it (like in, use the strap and always use the newest GT-31, you might need to replace it now and then...) :((.
Although there was lots of chop/boat waves I did occasionally find some flat water and was able to open throttle all the way.
I'm still massively impressed with that board and will soon try a 10.4 on it since the 9.5 works like a dream (and need a small repair).

13th July 2010, 07:49 PM
Duracell, just seen your question, and a lot of the rather emotional responses received! I think that as some mentioned you find the Size of Sail to Wind-Range to Board that fits your skill and conditions, yet this is not ROCKET SCIENCE.

While not as advanced a rider as some of the ones on the response list, here is MY overview of sails for each wind range and with the optimal, avg. wind-strength per sail.

SL 10.5__|_____08-12____|___10____|___5___|
SL 9.50__|_____10-14____|___12____|___6___|
SL 8.50__|_____12-18____|___15____|___8___|
SL 7.50__|_____14-22____|___18____|___9___|
SL 6.50__|_____18-30____|___24____|___12__|
SL 5.50__|_____22-34____|___28____|___14__|

Remark that by SL = I denote Slalom/ Freerace Sails with at least 2 Cambers (I use NP and Simmer 2XC/3XC), while the Sizes are indicative. The Ranges shown are for for Slalom/ Free-Race boards above 100L - smaller boards act /react differently. Rider Weight = 88 kgs. Note that OPT denotes OPTIMAL, which is a Median performance point OR a Sail to Size "Perfect" wind strength...

I checked the coarse list above with NP and they agreed for the last year's NP RSS/RSR series (i.e. Slalom/Racing).
There are a couple of IFs though:

Racing/Slalom sails are "heavier" given all the Cams, thus more difficult to handle while slogging; They also plan a bit later, BUT can handle nuclear winds or gusts better!
Freeride Sails with 2/3 Cambers are more amiable and easier to handle in maneuvers. However, pon Similar Size as the ones shown above they appr. 0,5 m2 to provide the same power as the Racing Sails
Freeride Sails with NO Cambers are the most fogiving, thus easiest to handle in maneuvers. However, for Similar Size as the ones shown above they appr. 1 m2 to provide the same power. Because they have a pressure-based batten enforced profile, they are "softer" thus loosing a LOT of power in Lulls (as the profile flattens out).
On Sails, there is a NEW category for FreeRace Cam'ed Light-Wind Blasting sails that have a Deeper more low-end powered Profile Template (which is tough on high-end); These are sails like NP Helium and Severne Glide, may be quicker than the list above by at least 1/2 knots. Thus a Racing 8.5 m2 helps you reach static planning (i.e. without pumping) from 12 knots, while Helium according to NP and RIKS help you plan from 10 knots (remark these are the numbers for a 89 kg!).
On Rider Weight, as you are 8 kgs lighter then you can probably remove a 1-2 Knot(s) at the Low-end of the range of each sail, thus you should be able to plan a 8.5 m2 on a 120L SL from 10 knots.
Finally, on Board "Easy Planning" potential, width and weight means a lot as we have been all discussing in our previous thread (http://www.star-board.com/forum/showthread.php?t=8705):cool:

That's all from my own experiences. If there are any radical departures let's hear it from the TEAM too...

R. ChrisN

14th July 2010, 02:12 AM
Like always, very analytical and very correct according to me, Chris.
I fully agree.
Another table to copy and paste onto my dekstop.
Personally, I would also subtract 1 - 2 knots at the low end for my weight of 86kg.


14th July 2010, 10:48 PM

I like the table, but I would question the OPT Knots for the 7.5, 6.5 and 5.5. All seem high, especially the smaller sails. For me at 77kg on a iS 111 and a 105 liter free ride board on cambered race sails (from 6.6 up).

7.5 - 16 knots
6.5 - 19 knots
5.5 - 22 knots

The question is who does your table fit? What type of sailor and experience is necessary to use the table to select a sail size? It seems to me that the type is - a highly skilled advanced or expert sailor.

Nevertheless, thanks for your input.