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Old 5th September 2006, 02:52 PM   #11
PG
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Default RE: iSonic105 technical ride

I am somewhat surprised of the "consensus" to recommend huge boards for featherweights (at Ricbra's 66 kg). The iS133 is 80 cm wide, and the iS145 is almost 90 cm wide...

I would think that the law of "diminishing returns" comes into effect quite quickly. With the same sail size it ought to be more fun to have a board that planes almost at the same time, but is much more manouverable.

For a small guy it seems that a board around 70 cm (like iS115) wide would be sufficient as a lightwind racer, especially with decent pumping technique.
On the other hand, if the wind is strong enough for a 5.5 then a much smaller board would make sense. One with an optimum sail of about 5.5 and a max sail of 6.5. This ought to be not much wider than 60 cm (with a corresponding volume of about 95 liters, offering float like a barge).
My honest opinion is that the iS105 does not fit particularly well into a two board quiver for a 66 kg guy... It is too small as the biggest board, and too big as the smallest.
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Old 6th September 2006, 12:59 AM   #12
steveC
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Default RE: iSonic105 technical ride

I weight about 70kgs, and I tend to agree with PG's comments. Very high volume boards really won't buy you much unless you also focus on matching them with very large sails. Given a sail limit at 8.5, I think that I would limit the board size to the iS111, or maybe the iS122 tops. Personally, my biggest board is about 115-120 liters, and my biggest sail is 8.3. While I can't claim to plane off in 6-8 knots, I find no difficulty at 10 knots with reasonable glide through the lulls. I think that it's important to remember a change from the freeride Carve to a iSonic slalom will most likely give you both a higher speed potential, to include a quicker planing capability, with the quicker rockerline.

However, before you go too far down the road, I would give yourself a chance to experiment with the iS105. Although an 8.5 is a bit large, you might find that it will tolerate it well, especially if you match it up with an appropriate fin.

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Old 6th September 2006, 06:34 AM   #13
Ricbra
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Default RE: iSonic105 technical ride

Hi PG and steveC,


While I do tend to agree with you based on commom sense and physics my own experience leads me to a different conclusion given certain conditions.
IMHO in fresh water and gusty winds more volume won't hurt much either way low or high winds. Example: with my C111 and 6.5 GTX I?ve never felt it to be too big for that sail size at the conditions above. However with the same combo but at a sea bay my C111 felt really big. I could have gone few liters less easily.
Same experience when I went to Aruba where I could easily sail smaller boards compared to my place when powered up by same sail size. So density of water and wind play a considerable difference.
I might be wrong in my conclusions but so far I could not think of any different reason for.
A little more volume puts you on a place sooner and if the gusts are not long enough you might keep slugging with a smaller board.
My point is how much volume versus sail size will work better?
I'm not a FW guy and do not want to go that way but I think I would plane in 7 knots with FW and 11m sail. Having said that what would be the earliest non FW planner for a 8.5 sail?
I wish I had the opportunity to test different sizes to compare them and make the right choice.
I'm glad I can use this forum to get some valuable opinions and experiences though.

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Old 7th September 2006, 01:44 AM   #14
steveC
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Default RE: iSonic105 technical ride

Hi Ricbra,

Other than my trips to the Columbia River Gorge and the Delta (east of SF Bay), it's pretty rare for me sail in fresh water. But, even when I have, I really haven't noticed much difference in my ability to plane. However, I'm aware that inland locations can have very different wind, especially if its dependent strictly on thermal conditions in combination with certain types of topography.

I understand your point that a bit of extra volume is your friend in gusty up and down wind. Yet, for myself, I view volume more in terms of simple float rather than the key to early planing ability. In my mind, the character of a board's rockerline is what makes the real difference. Of course, most high volume boards tend to have flatter rockerlines that promote early planning.

The real question is how big to go. My limit is about 120 liters because that's tons of float for me. Really, 100 liters offers me excellent float, and it readily supports a 7.0 sail, so it's a more desireable choice most of the time. But, if I need to go with an 8.3 sail because of real light winds, I need the bigger board and fin to support it. Given the fact that you have set your sail size at 8.5, and because your focus is not oriented towards a FW upwind/downwind approach, I doubt that volumes greater than 120-125 liters will not buy you much.

Another way looking at the situation is in terms of maneuverability. Sticking with just the needed volume, I find that I get to maximize maneuverability and nimbleness. I guess that is why I recommended that you experiment a bit with the iS105. You might be surprised.



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Old 7th September 2006, 10:19 AM   #15
Ian Fox
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Default RE: iSonic105 technical ride

Volume usually also means width and surface (planing) area in modern boards, which in turn (usually) help the effective and efficent use of larger fins ; both factors definitely provide early planing and marginal conditions advantage/s. Especially for lighter riders (who will be overpowered by sail earlier in the gust/s), a gusty conditions combo of slightly more "board" (read : volume and planing area and fin) with a smaller sail can really be a more advantageous (and more fun) option than more sail on a smaller board in the same (gusty) conditions.

Likewise, in gusty (and moreso offshore) conditions, the chop (vs windspeed) doesn't normally develop so badly (relative to filled in wind at the "same" speed, and/or more onshore conditions). Accordingly. the disadvantage of having too much board for the chop arrives later in the range of gusty/offshore conditions than filled in, or more side/onshore conditions.

Likewise, if you really analyse it deeply, often in gusty *marginal* conditions, the gust/s just don't last that critical time to allow the rider to pump the board fully thru to the plane, and the board always seems to be "sticking" (c/w a more filled in wind at the same "speed").

In those gusty *marginal* conditions, carrying the extra volume/area/fin can often be the key advantage to getting the gear planing, and then it just keeps running. Yes, for sure, some guys are pumping and early planing wizards, (and others very legitimately choose and tune not to be.. a very important personal choice) but even the wizards can still struggle when it gets marginal enough. Naklua. Last week.

Cheers ~ Ian

[ Sidebar here is that a skilled sailor won't statistically (numerically) need much more wind to get an iS101/105 planing than (say) iS133 or iS145; but the available power from a wind variance of just 1 or 2 kts in that threshold range is very significant. Worse, when it is gusty, or not clean wind in that range. If you're sailing a lot in that zone, the difference can be everything. ]

I'm into speed and small, but planing slow is always faster - and funner- than not planing
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Old 7th September 2006, 10:59 AM   #16
hans kleingeld
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Default RE: iSonic105 technical ride

Very clear explanation Ian. Last Monday I used the iS105 with OD7.5 in gusty conditions 12 tot 20 Kts. With my weight of 95 kg the iS105 really isn't a good floater in windlulls. The shallow water was saving me a couple of times. In deep water, but also for planing through the iS125 with 7.5 would have been the best option to make most fun concerning planing time and about the same topspeed!!
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Old 7th September 2006, 10:47 PM   #17
Ricbra
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Default RE: iSonic105 technical ride

Ian,


Thanks a lot for putting in a clear way what I do feel at my place.That is exactly what I have very often.
Many times winds are in the 6 to 10 knots range when with HS133 and 8.5 I can plane at the gusts with proper pumping but never could with C111.
When it is a bit higher say 8 to 12 knots then I'm planning almost all the time thanks to the amazing capacity of keeping on a plane that HS133 has, and here again I believe the extra volume makes the difference.
I believe and am eager to prove it that at such conditions I'll struggle a bit with iS105 as it will stop planning way sooner. I'll see.

One interesting point is that I can plane a bit sooner with a 38cm fin of same design and supplier - I guess - than stock 42cm. It seems to be less sticky. It also doesn't point upwind as well though.


steve C

It's really interesting to see how people make their quiver choices. It does make a lot of sense I also like less weight and nimbleness it's much funnier .I'll follow your recommendation and see how much iS105 and HS133 overlaps before deciding which iS to get although it will also depend on what will be available.
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