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View Full Version : Is volume that important?


Unregistered
25th November 2008, 05:57 AM
My windsurfing friends have been scratching our heads over this. We've tried boards from 1997 to 2008 vintage.

The boards from 1997 are longer and narrower for their volume and the 2008 boards wider and shorter for the same volume.

In the past if you wanted a wider board you then you had to find one that was also longer and had more buoyancy.

My 1997 mistral slalom 92 ltr x 55cm slogs fast but takes half the bay to accelerate to planing speed. 2005 Bic Evolution 112 x 62 cm planes up in half the time at half the speed but displaces water less well than the pin tailed mistral. My 80cm GO slogs painfully slow yet has the broadest "flight envelope" of all at seems to plane when traveling below 10km/hr.

A 280 L 70cm longboard planes at 12 knots with a 6.5 but becomes uncontrollable at 30 knots with that same sail yet won't plane with anything smaller. A formula board planes at 8 knots and is controllable (for an athlete) with a 9 meter in 30 knots.

The performance variable here seems to be tail width, not flotation. Would it then be possible to make a "no volume" formula board from marine ply? Has anyone tried to "boat launch" a no volume board from a planing start? How about a very thin 245 x 70cm 60 ltr board?

Is it possible to design a board that could "plane up" immediately enough to eliminate the displacement/buoyancy stage altogether? Wouldn't want to stray far from the beach, but could it be done?

I've seen footage of a Windwing user planing with waterskis. Is the fact that a sailboard rig generates no upward force at low speeds the limiting factor?

Per
26th November 2008, 03:06 AM
A kiteboard is basically a no volume board.. Water skiing and wakeboarding all depends on no volume boards.
A 100 x 250 cm x 2cm thick board on 12 litres of volume with a 70 cm fin and a 11 m2 sail.... Possible? Yes... But why? It would need a quick waterstart and very steady wind as you would have to keep it moving all the time. It would be difficult to design such a board stiff enough as the natural camber og the boards we know (being 10 cm thick) will stiffen up the board a lot (like a hollow mast). The flat board would be more floppy..
One advantage I see though is that you could keep a whole quiver of boards in a normal single board bag ;-)

Per

Ola_H
26th November 2008, 05:08 AM
Somtimes volume helps http://www.youtube.com/watch?v=ggzUTpUXJ6U...

Unregistered
26th November 2008, 07:16 AM
This all really came about from the inquiry of some friends who sailboard but come from a wakeboarding background. They were surprised that volume was such an important dimension when they were starting out.

Obviously a kiteboard needs no volume because of the vertical lift of the kite, and the fact that the kiteboarder waterstarts with the sail already traveling at 20 knots or more. The whole " power =square of velocity" thing. But kiters do use surf style boards in the 20-60 lt. range.

It's true that a ws board's volume also makes it structurally stronger. But on some of the boards of the past it seems like overkill, esp the older racing long boards.

It also makes the sport safer, especially in cold water.

What we are wondering is; with the short wide revolution nuking the limited sail range of past board shapes, which were longer and narrower and more buoyant, what the ultimate wide/low volume shape could look like.

Example from the 2004 exocet board range: the S Series: 235 x 80cm 125 L and a sail range of 5.0 to 11.0(! )

The longer and narrower Speed Slider 255 x 69 and 120 L with a range of 4.5 to 9.8.

Personally i'd like to sail the same board from 11 meter to five conditions and carry one board instead of a possible three, a formula esque board a freeride board and a "highwind" board.

Or perhaps fit 3 "wide ply boards" into a single bag. ;)

Starboard deserves major kudos for starting the trend and making planing windsurfing less of a "boutique" sport for the high wind endowed.

But i'm not here to simply boost Starboard. The industry should double the effort of looking into real world performance , reducing gear redundancy and increasing portablity. The world's economic condition and the numerous alternative sailing sports waiting in the wings should be ample motivation for this.

Long live sailboarding, in whatever form it eventually takes.

Unregistered
26th November 2008, 07:30 AM
Thanks for the video Ola, entertaining! Wave sailing? Now, if that same board was wider but not more buoyant, would it have planed? Or would a wider board have just needed more sail power, a bigger sail and more weight? A paradox...

Per
26th November 2008, 01:41 PM
Funny video, and the reason why I at 100 kgs dressed up don't have an 80 litre board.

Actually Starboard have been quite leading in the "one board to suit all conditions" for a while. The Hypersonic was supposed to carry from 5 to 10 m2 sails. My Aero 127 is funny with both a 5.5 and a 9.0. The problem with these kind of boards is that when you reach a certain level you will really feel the compromises built into these designs - The HS is NOT an early planer and the AE is NOT fast in a blast. Soo back to the drawing desk again to move a little rocker, rail, strap and wolume and PUFF! the compromises have now moved - to somewhere else...
I'd love to have one board and three sails to cover everything from 5.0 to 11.0 conditions whether it would be speed or manoeuvre oriented sailing..
How would such a board look???? Definitely short and VERY light, but how do you design a tail that will carry a 32 AND a 70 cm fin? A tail that cuts corners on waves and go at high speed in 11 knots of wind.
I believe it's possible.

Screamer
26th November 2008, 04:13 PM
Guest
I wouldn't believe quoted ranges too much. Have you tried those Exo boards with 5 and 11m sails? As Per said, when you know what you want, compromises become a bit too annoying.
Real world performance demands volume, for now.

I would also like to have one lens 12-300mm (f2.8 please) for my Nikon, but..... not going to happen in the near future ;-)

Farlo
26th November 2008, 06:03 PM
Yes those sail ranges seem exagerated, notably towards the small sizes. The Exo S4 will carry an 11 sqm sail, but the same guy with a 5 sqm sail will probably enjoy anything narrower. A 80 cm wide board in 25+ Knts is no fun, whatever the volume. The practical range is rather 7.5 ~10 sqm (which is quite a lot already).

steveC
27th November 2008, 01:34 AM
When you really think about it, a sailor really needs to have a minimum quiver of 3 boards to sail in the ocean venues I focus on. If one only sailed on lakes you could probably reduce the number of boards to possibly 2, especially if the fetch is relatively short. But really, as suggested by others above, a lot has to do with matching sail sizes to the boards. The short and wide boards of today definitely optimize the viable sail range possible, but there are still undeniable limits. All you have to do is see the sailor hating life using a board that is too big on a huge day. Really no fun at all.

As for the expense of having multiple boards (I'm currently carrying 6), the key theme that I leverage is keeping the boards for a minimum of 5 to 6 years to get my money's worth. With the economic trends we're experiencing now and for some time to come, getting your money's worth will be a paramount concern for some time into the future.

Farlo
27th November 2008, 03:57 PM
Volume is important to bring you back home when wind drops at the end of the day. This being said, modern wide/short/flat boards have similar sail range than longer/thicker boards of same width for less volume. I recently dropped my 126 L light wind board for a 103 L of similar width and I use exactly the same sails in the same conditions. No noticeable difference in speed or planning threshold but much more confort and control. So yes, it is a way to optimize your quiver (I just carry two boards now).

John Kemsley
27th November 2008, 04:15 PM
Hi having had a HS111 and HS133, and the only difference being volume/thickness I always felt happier on the 133 (which I still have), but then at over 90kg it may just be the self preservation factor when the wind drops.

Farlo
28th November 2008, 12:35 AM
In light wind you will apreciate ~30 L extra buoyancy. Of course the 126 was maybe a bit more nervous and kept planning in lulls better, but it became cumbersome quickly once overpowered. With 103 L x 65 cm, I can float comfortably in no wind, plane early in 12 Knts and still enjoy 20+ Knts. My Electric Rock was also 103 L x 63 cm, and an early planner too, but was nothing fun in 20 Knts + chops for 68 Kg (maybe less at that time).

feuser
4th December 2008, 03:41 PM
Only the length and the circumference are being the only important things.
The volume as compared to the width for early planning and the bigger sail is not important, maybe for floating you home but really HS 105 uphaul & slogging no problem 80Kg.

Hope this helps.

Unregistered
6th December 2008, 11:36 AM
Yep, can't overlook the ability to slog home when the wind is done which flotation provides. Narrow boards definately slog faster, as they displace water better.

The only kiting ( a no volume board example) i've seen has been in the premises of a safety boat if shoreline access is a problem. On small deep lakes i've sailed on this is especially true. Otherwise i've not seen a kite user stray too far from the beach. Though many definately do. I'd want some relaunch experience before doing a multiple kilometer tour.

Interesting that many of you have mentioned that excess volume compromises control. Couldn't agree more. Being caught out in 30 knots on a 250l raceboard is hectic. Being overpowered on a 120 l freeride board is too.

I used a 112 bic for a long time, even in 4.5 weather. It went upwind in that sail size well enough at least. But turning downwind and holding it together was tougher and jibing in rolling chop was difficult.

Many sailors ive seen carry 110- range Tiga X-Game style boards with 40 cm fins for 10-18 knots but quickly downsize to narrower bump/jump boards and 25 cm fins when 20 knots plus comes around.

As for a one-board "best compromise" Starboard had the Hybrid Carve a few years ago. Seems to have been dumped.

Fetch is a big factor, as is temperature. It may not be a question of a "best board" for low fetch (wide sail-carrying boards seem best). But on hot summer days on lakes, the wind mass is not consistent at all. A kite might reach into the "infinite fetch" just above the lake surface and best any sailboard rig.

As for planing through lulls... i don't think volume has anything to to with it. If you're planing then the board's not displacing water and thus creating no buoyant force.

A wide board like the GO and a big sail seem to keep you going when a narrower freeride board would fall off the plane.

Unregistered
31st December 2008, 06:07 AM
No. It is all about DISPLACEMENT not volume.

The simple rule of buoyancy.

An aluminium dingy has about 10L of volume but can float a 100kg engine plus 5 people.

Unregistered
31st December 2008, 05:04 PM
I failed physics too. !

Unregistered
31st December 2008, 10:46 PM
An aluminium dinghy has thoasands of litres volume "of displacement".

Thats why it floats with all that weight in it !

davide
1st January 2009, 09:58 AM
An aluminium dinghy has thoasands of litres volume "of displacement".

Thats why it floats with all that weight in it !
Problem is that for a windsurfer displacement and volume are almost one and the same ... we do not have nice tall sides on our boards ...

Unregistered
1st January 2009, 12:07 PM
Problem is that for a windsurfer displacement and volume are almost one and the same ... we do not have nice tall sides on our boards ...

To some extent ... but that correlation becomes increasingly irrelevant with boards that don't sink particularly combined with boards of greater width.

Farlo
3rd January 2009, 04:58 PM
This is true and not true. You need a minimum volume to get going (notably in low wind) then everything above waterline doesn't help for buoyancy. Once planning you could even consider that all volume is in excess. Volume seems more the result of many other parameters: you need a certain thickness over the desired outline to achieve the required stiffness with a given technology. Overall width and OFO are more relevant to define the fins/sails, thus the wind range. Modern shapes tend to be flatter with less liters; for instance a 90 L x 67 cm slalom board may now carry a 8+ mē sail. One reason is that excess volume = excess weight. On the other hand, new boards are always lighter and more controlable. So where is excess volume, and is it such an issue?

Ola_H
3rd January 2009, 05:06 PM
The big downside of "extra" volume relative the planing surface and rails is that it makes the deck rounder which means a less stable board both when schlogging and in high wind.

Adding volume around the center line as it is often done _will_ of course make you sink less when you you are at an absolute standstill provided you can keep the board balanced so that no part floats up and you don't fall off. But in practice I would say shaving of some liters to get a flatter and more stable deck shape will even in such a situation make your time easier even in sinking conditions.

A flatter deck and thinner board will also make the rig-board connection more "effective", inducing less roll. Just look at the iSonics. A board like the 09 iS86 is quite heavily sculped out around the mast track and towards the nose to get the feel of a thinner board while still keeping rails as thick as the designer wants them to be on this type of board.