View Full Version : For Ian Fox: is96 vs s100?

23rd October 2007, 04:39 AM
Hi Ian!

I would like to ask you what are differences between classic sonic 100 and its newest incarnation is96?

I am mainly interested in low end performance comparison (medium powered 7.6 conditions) for figure of 8 slalom racing? My weight is 75-80kg.

I am using is101 this season but I am considering changing it for a something more similar to sonic100, which is my all time favorite slalom board. Don't get me wrong, I like is101 very much, but I miss the "fun factor" of sonic100.

I find is101 easier to control in extreme conditions, so I suppose that is96 is also better in severe chop and high winds, but what about light wind characteristics?

I compete in slalom, mostly figure of 8, and we stop racing if the wind falls below 13 knots. I find 7.6 and 6.6 the perfect sizes for 99% of races. Sonic 100 was just great board for that range and my weight, do you think that is96 will be even better?

Is is96 more similar in ride to is101 or s100?

Does is96 also feature a dual flat bottom concept?


Ian Fox
24th October 2007, 04:05 PM
Hi Marko,

Considering your love for the older S100 (a pretty classic number) you'll find the iS96 very much in a similar performance "window". Any actual volume differnce in nett terms is hardly comparable, because the S100 carried a lot (maybe a little much) volume in a fairly thick front nose section, which (in almost all sailing conditions did nothing special), and the slimmer iS96 carries it's full 96 (actual) Lts compliment with a far less "nose heavy" distribution, meaning that all the volume in the 96 is really working where you want it, and none where you don't.

Although the overall width and outline are much more similar between S100 and iS96 than the S100 and iS101, the iS96 still offers some advantage (over S100) in the lighter or gusty end of the board wind range based on the wider tail area and stance. You'll understand that aspect already from the iS101, just scale it down a bit for iS96, but keep it above S100 and you'll be spot on. In comparison, for an experienced slalom guy the iS96 shouldn't be seen to have any less bottom end than the S100.

While the S100 had a pretty sweet drawn out carve style around the bends, the iS tends to improve on "carry" (or glide) thru the lulls, holes and turns, can handle more power going in/thru/out the bends.

Rails on the iS96 are not quite so sharp (in both shape and ride) and that cuts both ways, general average seems to favor the easier speed of the iS over the S100, although "old school" slalom fanatics (pun!) are less fazed by the slightly more demanding trim over/thru chop of the harder railed designs- and some die hards really like the hard engaged feel of the older rails, even if the speed is no better (or potentially more difficult in challenging conditions).

iS96 does not feature Dual flat bottom concept; that is again not always a downside, as to work really well DFC has to be really well dialled (in both design and on water trim). Again for guys who are already "acclimatized" to older flat rocker shapes such as the S100, well the iS96 definitely carries forward that style of ride (with new ease). By comparison, DFC trim really requires the board (rider) to be rockered well back onto the tail block of the board (not as in S100) to ge tthe most. That itself is not that demanding, just different, and I guess in summary, S100 certainly wasn't DFC (shape nor ride style) either !

Hope that helps a better comparison of the options !

Cheers ~ Ian

25th October 2007, 07:27 PM
Thanks Ian! Great answers!

Just a couple more questions...

Are you sure that nose volume in sonic 100 didn't do anything special? One thing that I do not like with is101 is pumping it up in light winds (7.6m2) and in choppy water. I find it hard to kick nose out of the water at my weight (80kg) with is101, when the board is submerged. I remember that it was not a problem with sonic 100. Nose was never submerged and I found it much less sticky to pump it up, probably because it is also a lot narrower in the nose and it really cuts thru the water easily.
On the other hand, I tested is111 in those conditions and I found it MUCH better for pumping. But with is111, I could stand on the board without submerging it.

I know this is not a big problem, but I find it very impractical in the light races, when you are somewhere in the crowded space and you make a bad gybe and loose speed (stop planning). I had quite a bit of problem with is101 in this situation, but never on my s100.

To make the long story short...Is is96 easier to pump it onto a plane in light winds (med 7.6m2 conditions) than is101? Sonic100 was easier for me...

One more question... Should I use bigger fins with is96 than with s100? SL2 36 was enough for me in light wind with s100, do I need 38 for is96 (wider tail)?


26th October 2007, 12:50 AM
Marko's comments here bring up an interesting issue that remains a bit hidden in the representations of current products. Even though online product specifications and representations include lots of valuable information, they don't really don't present or characterize volume distribution in each of the boards. I think that including a side view would be a great addition to the 2D representations. Seeing the top, bottom and the side view would allow folks to better understand the boards more three dimensionally and better depict volume distribution throughout the design.

26th October 2007, 03:30 AM
Steve, I am afraid that 3D pics and sideviews would not help much to understand how the board really behaves.

I remember that I had my new is101 in my hands and I was thinking...This board will be hard to control and hard to gybe....
After few days on the water, I realised I was completely wrong and board is super easy to control and gybes great!

But it would be nice if we could get some more info in boards overview so that we do not have to bother Ian and the rest of the team with our questions.

26th October 2007, 05:20 AM
Hi Marko,

I understand what you're saying about understanding how a sideview of a design might not help you grasp how a board behaves, but it would definitely better represent how volume is distributed in a particular model line across the various sizes offered, and it would suggest a lot more about the rockerline characteristics. Much can be discerned through subtle visual clues, and that would be significantly more than what's being related now (3 views instead of 2). Also, I think the 2D depicition is much more realistic for Starboard than the 3D approach, because one can't see the 3D view across the model line now (probably more expensive to do overall).

Ian Fox
26th October 2007, 02:00 PM
Hi Marko,

If we disregard aero arguments (applicable only really at very high speeds) then the only use of the extra volume in the front of the 100 would be in extreme sub planing and uphauling.. ( not really "real" slalom race issues I think you will agree ;)

At any sort of normal stance and minimal fwd speed, the upper side of the S100 nose area is well clear of the water and not acting in any functional way (OK, generalisation, but you get the idea). Simple test for that is to thin that section out (thickness) wise and go test.

With iS101, there is a much lower nose scoop/rocker, and combined with the extra volume (and width) distribution at the back of the board (driving/keeping the iS101 tail more "up" at any sort of fwd speed c/w narrower , thinner S100 tail), this all gives the iS a flatter (less nose raised) angle on the water( even in sub planing) and can appear as you described. Taking a slightly more aggressive, rearward stance on the iS101 can compensate for some of that.

More subtly, but importantly the real difference is more likely in the rails (as mentioned in my above post), where sharp(er), boxy rails on the S100 have given way on iS to a (slightly) softer, more tucked profile (which improves top end control/rideability/confidence etc). In isolation, that could be considered to be a potential for reduced "marginal" performance and/or early planing ability.... Especially by riders who had evolved good rail "edgeing" technique on older, narrow, sharp railed slaloms to get going (earlier) in marginal/sub planing conditions (might sound odd to those who don't, but it's real, they exist and yes it's an art). However (the big BUT...) when considered as part of an overall package, adding (back) in a wider tail (increased planing surface area) and increased ability to handle bigger fin area (in marginal conditions) , any "loss" due to softer rails can pretty much be negated - and an overall better package achieved (by most measures !!?? - especially overall range, not only of the board itself, but a board that is more tolerant of sail size range, that's to say can more adequately handle overpower situations for example).

Again, to get the most from this new style really does require a few minor style/technique (and even tuning) adjustments - and I agree the initial "feel" might leave hard rail addicts a bit underwhelmed in marginal conditions. Pretty quickly offset when viewed in overall context !

Does the iS96 plane earlier than S100 ??? Marginal and decided on technique. A more powerful, rear (and fin) focussed technique will show less disadvantage to the iS96, whilst a smoother slide forward, rail edgeing plane up technique may favor S100.

We're pretty strong advocates of providing as much information as possible, and YES, Steve, I agree in general more images 3D animations etc all look good and can help, but for sure the subtle detail variances that really relate to this issue (and similar) would not be so easily portrayed or observed in even the best 3D animation. And even if fully visible, "interpreting" these into comparative performance/behaviour is an even further descriptive challenge (yes, happy to stop writing anytime :) )

Cheers ~ Ian

26th October 2007, 03:17 PM
This is really an accurate and honest description of how shape details influence performances, and about one of the biggest curiosities of mine!
I am reasoning on Ian's contribution not comparing S100 to iS94/96, but rather thinking about performances differences between older narrow boards such as RRD 281 and 278, and more modern "wider" shapes as my S95. Now I understand (hope so at least). On the S95 with 7.0 I use a 34 SL2 fin, while on my older boards with 6.9 it was much smaller 31 (Tectonics Spitfire design) or 32 (elliptical Deb) from RRD. I used to have a 33 too (Spitfire design) and it felt BIG and slowing down the board, even in marginal conditions! And in fact it was, as early planing was achieved by efficiency rather than power; sharp rails and small fin, rather than big sail and enough fin to push against. And it finally explains how the bigger feeling S95, with thick rails and wider beam and tail, feels much easier in high winds.
Only, I must observe one thing; and this relates to another thread about changes. It seems to me that in the end the wind range has been shifted, rather than just expanded. Older boards, once up and planing, were incredibly fast even in light winds, while my S95 is a dog when not fully powered. In higher winds, S95 range is after all similar to that of my older boards; by sure it feels much easier, but the RRDs felt more efficient and... do I dare to say... OK, better no.

So in the end (and not considering the extremely hard to sail, and rewarding, RRD281): both RRD278 (84 lts, 55 wide, 32.5 tail) and S95(100/94/96?) (around 95 lts, 58.5 wide, 38 and up tails) share about the same optimal sail range, 6.0 to 7.0; once planing, older boards were competitively fast against bigger stuff (I'd say faster) while for modern boards planing is not enough, they need full power (in marginal 7.0 winds, say 12-15 knots, I can plane my S95 but whoever on bigger slalom stuff is passing me, while I used to kill everybody on my older boards; things change once in the 15-18 and up range); modern wider boards can carry bigger sails and fins, but this does not seem to expand much the "top performance" envelope in light winds, just enhances accelleration and upwind a bit (and slows down top speed...); and modern boards can go out in overpowered conditions better than old ones; but nevertheless, outside of their optimal range, I don't see modern boards any competitive against "right sized" stuff. So what is achieved in the end? I'd say just the ability to face an extremely wide range of conditions; but competitive performances are achieved in the usual much smaller optimal wind range.

Just my sailing impressions, and some reasoning about ian's great post.

26th October 2007, 06:40 PM
Ian, thanks once again for a very detailed and honest answer!

Geo, you have to look at the slalom boards from a little bit different perspective...
New slalom boards are made for BIG range because it is allowed to register only 2 boards per event.
Also, new slalom boards are made for BIG guys (because they are usually the fastest).

Big guys need a wide board that allows them to use BIG sail and carry them thru lulls and gybes. But they also need excellent top speed and easy control because they will use this board in very overpowered conditions.

I can see from all this above, and I can feel that every time I step on my is101, that it is a board for BIG rider. I think it is a ideal board for 90+ kg riders for overpowered 7.0/6.6 conditions in gusty winds and choppy water.
Is101 goes unbelieveable well thru chop and is very fast with bigger riders. I even used it once in severe conditions with 5.4 sail and it was MUCH easier to use than my old sonic 100 which was almost unmanageable in such chop.

I remember few years ago, Kevin Pritchard used to sail S100 with 7.6 sail in lighter winds and win races. I am 100% confident that he would choose 8.4/is122 in the same conditions nowdays, so yes, I agree that range of modern boards is shifted. But they still have much bigger range than older boards.

But I am afraid that ligher riders are forgotten in this new slalom program. Yes, new boards are very easy to handle also for light guys, but they are simply not fast enough. Lighter riders do not have problems going thru lulls and in gybes, their biggest enemy is drag. So they have to use narrow boards, smaller sails and smaller fins. If the new narrow boards (is96/86) have softer rails, I am afraid they will not be as competitive in light winds as older, hard railed designs.

For me, I am somewhere in between (80kg), and I think I was faster in light wind with sonic 100 but better overall in high winds and heavy chop with is101.
But still, I find s100 much more exciting and more enjoyable to ride!

I was hoping that I could replace is101 with is96 and get that sonic100 feeling and lightwind performance + great control of is101 in chop.

27th October 2007, 01:52 PM
But in the end we are saying the same thing... I guess you have to decide, either "that sonic100 feeling and lightwind performance" or "great control of is101 in chop". Efficiency vs. control.

Ian Fox
28th October 2007, 06:50 AM

Maybe "rail-centric" vs "tail-centric" is a better summation ??

It's very much the case that to get the most from the newer boards, the rider must employ a style/technique that focuses (more) on use of the tail block/fin combo and less on the overall mid section(rail line) of the board. Again, the differences are subtle - but real - and can significantly influece factors such as early plaing.

There are very strong efficiency advantages (better lift to drag ratio) in using a wider (and shorter) planing flat such as evolved thru FW and now into slalom. The secret is to maintain (thru design, tuning, rider skill and 1000 other variables) the longitudinal trim, because if you loose (control of) that, you quickly have a wide LONG planing surface which (you guessed it ) doesn't perform as efficiently as a narrow long one. With better (more draft stable) rigs and improved fins, there is (more) room to explore (and exploit) the potential of the (theoretically) more efficient L/D of the wider tail - and produce an overall "better" package (obviously, subject to personal vs. average or competition opinion).

With these wider tails (and "softer rails"), the other critical but again subtle design change is the rockerline, which needs to be adjusted such that the board (by nature of rocker) trims back at working/planing speed onto a shorter (but wider) rear planing flat than the same "size" (volume) "narrow" board. (OK, loads of generalisation here, but minimising the variables for ease of discussion). Basic fundamental objective of the Dual Flat Concept DFC is to provide a distinct break point in the rockerline to help "clear" the mid/front section from the water (at speed).

So once you have done that successfully (and got other criticals like jibe, control, bounce) under control, the mid and forward sections of the board (and rail) are a lot less involved in the primary role of "planing surface" (and working efficiency) than they were in a long, narrow board - and along the way have been "optimised" towards increased control (softer or more tuck) - which is not just a safety or comfort factor, but allows the rider to push on when previously (or otherwise) they would start to reach control limits in both a mental (rider) and physical (board) sense.

Important differentiator too is the subtle difference between description of rail and tuck. And how (or where) it varies along the rail length, in relation to the boards outline (short+wide vs long+narrow). In general terms the "rail" defines the whole cross section of the edge of the board, the radius or outline of the cross section from deck to underside. In more specific terms, it can define the actual join (interface) of the curved side of the board to the flat underside, the actual "edge" or corner. In all slalom boards the rail to bottom/underside intersection (at least at the tail and mid "working section" will tend to have a clearly defined "hard" (corner) release edge to ensure a very clean (efficient) release, (compared to say, a fully rounded and soft "edgeless" Malibu board rail). However, by increasing the tuck on the rail before it reaches the underside, you effectively reduce the "bite" of the rail (especially when considered in a lateral or sideways movement).

( So what ?? Boards move forward, not sideways… Exactly ! But when you pump (even modestly), although the result is to push the board in a forward direction, the pumping action of the rider against the board/rail/fin is trying to move it sideways. And when (moments before a deadly rail bite at speed) the board slips or slides, that rail if effectively moving….sideways!
Of course these are the two extremes (sub planing and spinout ) - in between the differences are there as well. )

iSonics are (by comparison to say even Futura or S-Type) still relatively hard railed, so this whole discussion is really on very fine subtleties.


Some more quick comments on some of the other discussion points above..

The iSonic range during evolution and development benefits from a lot of comparative testing against older model designs, often in marginal slalom conditions (Thailand), and by light riders such as Tiesda and Per (RIP), not just the heavyweights (in a physical or political sense). Yes, it's true the Antoine's and KPs have a serious input and yes it's true these are racing machines in constant evolution to remain at the top of their game, but at the same time the "roots" of this development have serious light weight test rider involvement.

It's also realistic to note that a 70Lt board optmised for use in 40+kt conditions by a 100Kg A2 is probably going to be (ideally) a little different from a 70Lt slalom designed for use by a 50 Kg Japanese lady racing Kanaha in 20 kts. Both would be on the right "size" board. A key factor here would be water state / conditions variance, as well as the obvious rider weight/trim factors.

Increasing the range of the iSonics (both the boards basic wind range, and it's ability to perform better outside the "ideal" sail size range) is a huge practical benefit to the average sailor - and the sport - not just top PWA pros racing under "2 board" restriction. The general trend across the sport in recent years is towards more (but better or well behaved) volume (for a given set of conditions) to improve range/versatility etc. That benefit doesn't stop at iSonic, look at Futura and even Kombat and beyond.. One of the extinction factors from the previous slalom boards was very clearly their narrow and very "edgy" range ; fast as hell in a very narrow range, and generally requiring massive skill and cojones (and maybe luck) to get the best from them in this narrow range.

The slalom market has grown and matured in this current "cycle" and the average customer has become more advanced, more skilled and more demanding of range and top end performance. On average, they are willing (or even demanding) to exchange a need to refine/update/modify their style or technique to take advantage of higher performance /range potential.

I'm personally from the old school of super narrow and massively hard railed slalom/speed boards, and can relate explicitly to the "efficiency" that Geo and others discuss. These older boards - with the right skill, application and conditions - could do some amazing things and bend a few rules. Still do. But by comparison to the overall "package" the new boards offer, their versatility is significantly restricted.

(anyway, now it's windy and time to go sailing)

Cheers ~ Ian

29th October 2007, 05:54 AM
Thanks to all the contributors to this thread. The whys of short/wide versus long/narrow are a lot clearer. I moved from long/narrow to short/wide more than a few seasons back. Went from fast enough to keep with the pack ,to back marker in our local drag racing; that is until I had the new kit dialed and my 'muscle memory' reprogramed. No doubt the new kit is more versatile and those entering the sport of slalom for the first time seem to make remarkable progress versus the previous generation. Some of the guys are still on their long/narrow kit and are fast and fluid for sure, but I wonder what might be if they invested in the change.

Was a similar change-over in snow skiing which has all but eliminated the long/thin in the space of 8 years; people entering the sport a lot easier, now doing what was seemingly impossible a few years back (the 'hyper-carving'), and numbers are healthy.

With reference to another thread on carve gybing the (high-wind type) iS it seems to me that we are still learning about the potential of the new WS design. E.g. like snow skiing's hyper-carving, it often pays to 'stack' the body over the inside rail when gybing - physics is physics.

29th October 2007, 02:24 PM

just to better explain your concept of "sideways moving". Actually, when a board is going, there is always a component of sideways movement. If that wasn't there, the fin simply would not work, or just act as a dragging device. That "sideways component", which in fact explains angle of attack, is higher when pushing hard against the fin and lower when going deep downwind and/or sheeting out the sail. Rails (at least in the tail) are actually almost continuously engaged.

Ian Fox
29th October 2007, 05:39 PM
Hi Geo !

Exactly, but in the description I gave I tried to simplify variables to keep it (relatively) easy to understand the differences in how the mid section rail is working to influence the characteristics at marginal planing thresholds of two otherwise similar outline boards (which was basically a main component of the discussion).

No question at all the rail around the tail is basically always fully engaged, but here too you find a lot less variance between new vs older rail profiles and tuck for that reason.
Rails in the mid section (as discussed) are a lot less engaged (by length) on short wide outlines than they are by length on long narrow. Again this is a major over simplification to convey as practically as possible the subtle design variances as they apply to the primary discussion iS96 vs S100 planing variances.

Cheers ~ Ian