View Full Version : Question to Ian and Remi on iSonic 145/155

16th August 2006, 05:42 PM
Hello Ian, R'mi,
I hope you can help me to make a right choise of a board. Last year I have ordered FT148 Wood from my local SB dealer. There was a mistake and a DRAM arrived and I did not take it.
The FT148 was a perfect blend of dimensions and liters for me. Now, I have to choose either iSonic 145 or 155. These look very similar to 2006 FT138 and Ft148, but beefed with liters (are these vertual or real, t.e. displacement?). Acoording to Liters I need iS145, but according to dimensions I need iS155 - very confusing!

I am 75-78kg and will use it in 7-10knots and in 10-17knots winds, open sea, salt water. (I have been on F155 for ~4 years now). Sails are 9.4 two-cam and 7.4 (which I want to change to ~7.8 2 cams). I want to have upwind/donwind and planning ability at least as my F155W which I love. My other board is freestyle/wave 85L which I use with 6.3 and below in anything >15knots.

Can you please advise me on which board to choose? (I'd want to order as soon as possible). Also, what is the weght of the iS145 and iS155 Wood?

Thanks in advance for any clarifications and help.

Ian Fox
16th August 2006, 06:52 PM
Hi Paul,

The wind/power range in the 7-8 kt range really drops off significantly and you could have struggled more on the FT148 in that range than the F155. For the really light wind stuff the iS155 would be the better choice, but considering yor sail sizes/rider weight and overall wind range, the iS145 wil probably be the better (overall) choice - unless you spend a significant % of your sailing time on this board right at the bottom end of your range. You'll find the iS is more efficent for a given size (and model size) than the FT (FT having a softer rail, a bit less effective in marginal conditions) so factor that in to your comparisons as well. Also for a 75kg rider, the typical quiver gap from an 85Lt freestyle/wave to your iS is going to have a more practical overlap at iS145 than iS155 (getting a bit extreme).

Maybe Remi has even more to add as he's been doing a lot of test and development in /around marginal conditions planing.

Cheers ~ Ian

16th August 2006, 07:45 PM
Hi Ian,
thanks for the reply (I am still waiting for Remi's).
I wonder how much will I loose on the lower end (7-10knots) if I use 9.4 sail and 66 cm fin with iS145 (can I put 66cm fin on iS145?) versus the same setup with iS155? And what about upper end
(in ~15knots) with 7.4 and 56cm fin?
Thanks again,

Ian Fox
17th August 2006, 11:51 AM
Hi Paul,

(Remi is most likely as locked out of our own website as the rest of us, so don't take his non apperance too badly ..)

While your sail size of 9.4m on the iS145 will be OK, an oversize 66cm fin is really overfinning this board; it will be rideable - and will help with actually getting the board to plane earlier in marginal conditions but as soon as you are planing, the 66 fin will really be overpowering the board, and esp with a medium weight rider not such a great or practical combo. Typically think about 58-60cm as being the max practical fin for the iS145.

Yes, you will lose a little bottom end range (obviously) with iS145 but overall you will get back more range in your quiver at your weight/sail and wind range, and if you were confident the FT148 was the one for you, then the bottom end of the iS145 won't be worse.

If you really will be sailing a lot in sub 10 kts or flaky wind, then think about iS155 bit otherwise the 145 will be a better all round choice for your weight/conditions/quiver etc.

Planing thresholds in marginal conditions are really signifcantly influenced by a number of variables outside our control (like rider skill, determination, pumping / water conditions and wind quality at x kts etc etc) . One advantage of iS is that it is a very responsive design to a bit of extra input (work) to get it going; meaning it's a very likely choice to run a slightly smaller board than "ideal" at the bottom end of the range in return for that same ("smaller") board giving back a lot more range at the top end of the range.

Obviously, there will some compromise in either case, it really is about minimising the overall compromise. Make sense ??

Cheers ~ Ian

17th August 2006, 05:36 PM
Hi Paul,

Sorry for this late answer but I was loock.

So before to answer as much I can, please let me know wich will your bigger sail.

All the best

17th August 2006, 05:40 PM
Hi paul,

Sorry I suppose that your bigger sail is the 9.4, in this case not necessary to go to the iS 155, beter to used the iS 145. But in 7 knots the best solution will be 11m? and iS 155.

All the best

17th August 2006, 06:46 PM
Will the isonic 155 plane earlier given same variables than the phantom? I imagine the phantom will be superior in sub-planing conditions?

17th August 2006, 06:48 PM
Thanks, Ian and Remi!
Just to nail it down I need to have a short answer on not very short question :) - I don't want to make an expensive mistake when buying a new SB beauty:

1) Will I match upwind/downwind and planning ability of my current setup of FW155wood (year 2001), 9.4 sail, and 65cm fin when I change the setup to iS145, the same 9.4 sail, and say 58cm fin (or should I go bigger)?
(I will not get bigger sail than 9.5 in a near future)

2) Can you please give width and weight of the iS145 and 155?

I really appreciate your help,

17th August 2006, 09:50 PM

Search the "Windsurfing School" archives (Roger Jackson's Forum) for discussions on the F-Type 148. Roger is an expert on that board and has helped a lot of people with tuning and technique. (The iSonic 155 is apparently a slightly modified F-Type 148, still 222 x 96 cm, but with some more volume and some tuning of the tail area for more speed from things learned from 2006 iSonics.)

You can use a much bigger fin than the stock 56 cm with a 9.5 for marginal winds for earlier planing. I use the 51 cm True Ames Shallow Water Weed (which is like a 65-70 cm Formula fin wrt lift) with my 9.5. And I also plan to get a 64 cm or so blade fin as well for use with my 9.5. I use the stock 56 with 8.5/73, and go down to a 52 with my 6.6 (haven't tried that last combo yet).

I too am interested in feedback from the Starboard team on iSonic 155/F-Type 148 versus the new Apollo, wrt planing thresholds and recommended sail sizes. And why is it so long (250 cm) versus Formula and F-Types? What does that get you in this new design?

I posted a similar question below, but no answer yet.


Ian Fox
18th August 2006, 01:50 PM
Hi Paul,

Q1) Will I match upwind/downwind and planning ability of my current setup of FW155wood (year 2001), 9.4 sail, and 65cm fin when I change the setup to iS145, the same 9.4 sail, and say 58cm fin (or should I go bigger)?
(I will not get bigger sail than 9.5 in a near future)

A1) iS145/58cm fin : Marginal wind upwind/downwind and planing ability will be close but marginally behind F155/65cm everything else being equal. Gap will close as wind increases. Speed in beam or reaching mode and control in chop (again, more issue at the higher end of these boards range) slight advantage : iS145
If you take the iS155, (wider tail/rear planing area) you can use larger fins (in a practical way say to 64-65cm) and you will get to F155/65cm
marginal wind upwind/downwind and planing ability (so say, sub 10 kts performance) but will not be as optimum at the 10/11 -15kt end of the range c/w iS145.

Q2) Can you please give width and weight of the iS145 and 155?
A2) iS145 is 88.5cm wide with tail width 60.2cm
iS155 is 95.5cm wide with tail width 66.8cm
Production weights on these two (and many other models) we don't have final yet, but consider as aproximates :
iS145 Wood ~ 8.0kg +/-
iS145 Tech ~ 8.5kg +/-
iS155 Wood ~ 8.5kg +/-
iS155 Tech ~ 9.0kg +/-

Hope that helps sort it, please let us know if more info required.

For Paul : I think Remi answered now re the Apollo inthe other thread.

Cheers ~ Ian

1st September 2006, 03:47 PM
Measurements,shape, and out line of the new I-Sonic 145 et 155 seem to be exactly the same than the previous FT138 and FT148 features.
So i am wondering if they are the same boards with a new name (marketing) or do they benefit from some significant evolutions (if yes can you describe them) that Ican not distinguish only by looking at the drafts and the specs on the web site.
Cheers Jrome

Ian Fox
2nd September 2006, 09:45 AM
Hi Jerome,

Yes, it's correct the decvelopment of the iS145 and iS155 are based (origininally) on FType boards. However the differences are also as significant as the "similarities". The difference with the tail (side) cuts is very noticeable in speed comparison (head to head) and the deck shape around the nose/forward deck has been modified to cater more for lighter winds and /or heavier riders.

Then you can take the FT's and race them against the iS's and you will also see evolution at work (or play :)

Cheers ~ Ian