Forums > Wing Foiling General

Basics: Board Volume

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Created by SpokeyDoke 3 months ago, 10 May 2024
SpokeyDoke
130 posts
10 May 2024 10:44PM
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Endless threads on board volume, but I still don't have a sense of what all the variations relative to rider weight actually mean in the water (aside from the very few boards I've tried, all floaters and one super-duper sinker wake board).

I'm particularly interested in just where the board surface is in the water when not moving as you go below your weight in liters, and the pros and cons of being at that level, particularly when you start dealing with chop/waves and getting up...(and I know board shape will make a difference, and feel free to comment on that)...feel free to add smaller increments too

+10 :
Even L/Kg +/- :
-10 :
-20 :
-30 :
-40 :
...

Velocicraptor
619 posts
10 May 2024 11:01PM
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-20 the board basically sits just below the surface when the board is completely flat. Move your weight aft and the nose is fully out of the water. If the board is long, efficient and light enough, I find this to be the best "all arounder" volume as it doesn't get thrown around by waves, but is still easy to get to the surface and onto foil. too far below that and you need to be overpowered to get to the surface and onto foil. Too far above that you contend with surface conditions.

The reason why there isn't a "correct" answer is that volume is only one metric. Length and efficiency are equally or more important. -20 liters on an inefficient board might be just as good as -40 on a super efficient board.

CFL Foiler
72 posts
10 May 2024 11:01PM
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Board shape has a big impact in how low you can go in volume and still have manageable starts. I weigh 90kg and just switched to a 48l Omen Flux and it is just about as easy to start as my previous 60l Armstrong FG. It is more technical to get to the surface but if you have your knee starts dialed I don't think it is really that much harder. Its just about knowing how to unweight the board to bring it to the surface. Once on the surface this shape just accelerates onto foil so easily. Very happy.

90kg / 48l: -42l

I do still ride my 8m CWC when its really light 8-12mph winds. But personally I would rather a larger hand wing then riding a bigger board. This is my one board quiver now for wing and prone. I switch to my 5.5 Strike when it starts gusting to 15

MidAtlanticFoil
716 posts
10 May 2024 11:10PM
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While it is easy to look at +/- Liters to KGs, the more accurate way to convey comparisons across weight ranges is by the volume ratio:

Board Volume (L) / Rider Weight (KG) = board volume ratio.

I'm only coming around to this method after years of experience. The BARG method in the other thread takes it a step further to integrate board aspect ratio.

As you go to a negative ratio, you will progressively sink the lower the ratio. As you sink, your body has a bit of float/volume to it as well, so getting as much of your mass into the water can help the board stay closer to the surface (think knee starting with a 90 degree bend in legs vs sinking butt down between feet. For my, my 40L for my 65kgs (.61 ratio), the difference between kneeling deep and 90 degrees makes a huge difference in depth of the board below the surface.

My old 60L (.92 ratio) would sink to my shins and deeper sometimes when standing. Also difficult to knee start/balance in choppy water

My new 55L (.85 ratio) sinks to knees/thighs at least if not moving. Easier to knee start at this volume in choppy conditions, as some of the surface chop goes over the board.

JonahL
55 posts
11 May 2024 1:13AM
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I think one of the reasons you hear what sound like wildly different ideas about optimal board size is that local conditions figure into it quite a bit. For instance, the spot I ride is very gusty and holey on the inside and the gusts can be very short and abrupt. If I can stand on my board sunk to my ankles or less I can probably get on foil with a 5 second gust. If I'm up to my knees or deeper I probably need a 10-15 second gust to climb to the surface and then accelerate.... If I was riding someplace with steadier wind or even slower, longer gusts, a lower volume board would be fine. Having some ability to move while off foil can be important or not so much depending on the spot.
FWIW, I'm at .84 volume fraction on a 5'10" x 20.5" 80L. I have a 5'7X 18.5" 65L coming that will be my prone and steady wind wing board

BWalnut
365 posts
11 May 2024 2:07AM
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Worth noting that you need to consider the entire equation to get a reasonable answer.

What is your riding style and goals?

What size foil do you want to ride?

What size wing do you want to use?

What wind speeds are common in your area?

Are you in the ocean or a different setting?

All of these things bring about very different and nuanced changes to the pros and cons of different board dims. Add to that that the industry is shifting right now towards midlengths and tons of new info is coming in about shape vs volume, so no one can really speak to being an expert in every variation of this answer that is possible.

For me:
River riding, 15-25 knots, flag out and ride swell is my goal. I prefer foils in the 700-900 range and rarely want to fly a wing bigger than 3.5m

As such, a relatively neutral volume board with length around 6' is my favorite.

For my style, when the volume gets too high, the board feels more sluggish in the air because this means the board is thicker, wider, longer.

When the volume goes lower, I have to sacrifice my wing or foil size, which for my style, is completely unacceptable.

boardsurfr
WA, 2312 posts
11 May 2024 2:09AM
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There's a couple of complications to keep in mind, which include water density, board weight, board extras and wetsuits, stance, and volume errors. Water density increases by 3.5% when going from fresh water to salt water. The difference is even bigger in hypersaline places like the Laguna Madre in Texas, where a 100-l board would float 5 kg more than in the Gorge.

Board weight comes into play because you'd have to subtract it from the volume. That would reduce "net" volume by 3-5 liters, or even more for heavier boards. Board extras like pads and straps are often not included in board weight, so increase that. Similarly, a wet suit, helmet, and harness can add a few kg to the sailor weight.

Stance is perhaps the biggest factor with respect to how far the board is under water. Here's an example. My wife's 50 l board seems to be a -12 l board for her. But if you consider the added weight from wet suit, helmet, and straps, it more like -20 l. When she stands on the board without moving, the wing just flying itself, she sinks almost to her hips. About 1/3 of her body volume is submerged to displace the extra 20 kg/liters. But if she kneels on the board, the water only comes to just above her knees, and the board is less than a foot below the water surface. So when Velociraptor talks about a -20 board sitting just below the surface, he must talk about sitting or kneeling on the board.

The "volume errors" can also be a big factor. Back when some windsurf magazines tested the actual floatation of windsurf boards, different boards would often turn out to have 10 liters more or less floatation than stated (for ~ 100 l boards). Sometimes, the volumes are "given" by the marketing division. Sometimes, the volume is from shaping software, and ignores added volume from glassing, sandwich construction, and EVA. For board in full sandwich construction, that can easily add a few liters in volume, even if the volume estimate for the core shape is accurate. Of course, brands might decide to simply estimate how much volume gets added to the shape, and include that in the stated volume. Or not. I've have "+20" windsurf boards that I could push fully under water if there was no wind and no movement. Considering the rig weight, too, they probably were closer to "+10" boards. With a wing, you may see the opposite effect even in relatively light wind, when the wing pulls just enough so you don't have to hold your arms up.

SpokeyDoke
130 posts
11 May 2024 8:21PM
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Thanks for the education, some really helpful input to consider that often doesn't come up in "what volume should I get" threads.

I spent a bit of time on a +5L Appleslice V2, and really liked being able to just sort of slide onto it and sit close to the water (and the feel in flight), rather than the hoist and balance on a perch required of the +25L Appleskipper DW board I'm riding now, but the quick and easy board speed of the DW more than makes up for it right now in the crappy wind conditions I have at home.

I imagine I'll get another smaller board at some point (like the look of the new KT Super K), just really uncertain what it would mean to go mild sinker vs mild floater, especially as I start moving into more challenging water conditions on my trips to the gorge

Hwy1North
175 posts
12 May 2024 1:13AM
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So much valuable info on this thread. Honestly, there are a lot more important factors than volume, like shape. I primarily ride in shallow water over mud flats or reef. Too little volume means being grounded. I prefer the feel of a thin deck because I prone surf, but it doesn't take much of an adjustment to ride a thick wing board.

Yesterday I was miserable on a 120 ltr 8'2" in 0-28 mph winds and large rolling chop climbing onto a cork getting rolled by small waves. If I were on a sinker, I'd be miserable sitting waist deep waiting for the next puff, getting rolled by waves....

Velocicraptor
619 posts
12 May 2024 8:48AM
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SpokeyDoke said..
Thanks for the education, some really helpful input to consider that often doesn't come up in "what volume should I get" threads.

I spent a bit of time on a +5L Appleslice V2, and really liked being able to just sort of slide onto it and sit close to the water (and the feel in flight), rather than the hoist and balance on a perch required of the +25L Appleskipper DW board I'm riding now, but the quick and easy board speed of the DW more than makes up for it right now in the crappy wind conditions I have at home.

I imagine I'll get another smaller board at some point (like the look of the new KT Super K), just really uncertain what it would mean to go mild sinker vs mild floater, especially as I start moving into more challenging water conditions on my trips to the gorge


Because it illustrates the impact of board shape and you are familiar w the boards.

I have a slice v2 and a v3 of the same volume (60L). The v3 has seemingly minor tweaks but it gets onto foil MUCH easier than the v2 at the exact same volume. In fact I feel like the v3 rides as if it's at least 10 liters higher volume than the v2. It's also more stable than the v2 due to the added length. They don't even look that different next to each other but they are very different boards.
point is - volume is a vague parameter.

ninjatuna
208 posts
12 May 2024 1:00PM
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I have 3 boards I have been winging on. I am only describing getting up on them.
board 1- 5'2 x 21 x 60L
board 2- 6'2 x 21.5 x 100L
board 3 - 7'0 x 21 x 65L
me 86ish kg

If lighter wind and no chop, can pop up knee start all 3 no issues.

If choppy, ( 2ft chop) board 2 and 3 still get up very easily. I only knee start them. They both start planing immediately and all I have to do is just stand up and pump. Stability is there with any movement. board 1 has to go to stinkbug. pain in the azz when the 2 and 3 have no issues. Pretty much dont ride board 1 any more and need to sell it.

I have a friend that just picked up a used board for towing around 35-40 liters. I want to try that on a good day with the wing. Have read in the past to about half your weight in liters is easier than just going like 10-25 liter below your weight. So if that works out, than I may have a 40 liter board in my future.


When getting up, I straddle them like a sitting on a surfboard until I am ready to go. Board 1 is pretty much under water 6-10 inches or so. Board 2 I am up out of the water by and inch or 2 if I get it flat. But I am usually sitting at an angle though since it has a narrow tail. so the nose is generally more up in the air and my butt is in the water. Board 3 again is sitting at an angle with the nose in the air. With me sitting in the middle, the water comes up to around the middle of my stomach. But with any movement 2 and 3 tops are out of the water.

airsail
QLD, 1347 posts
13 May 2024 5:37AM
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Me, 81 kgs, daily drive 74lts, 5'3x21. This boards gets me going in the lightest of wind, and I can always get back to the beach if the wind drops.

Tried a 52lts, great when the wind was blowing but found I needed one size bigger wing than what I would use on the 74lts. If the wind backed off getting back to the beach was a challenge and I found I stropped trying new stuff because getting going was a pain.

Settled on a 65lts for jumping when the wind is up, easy to get going or get back to the beach if the wind drops. The 74lts is now my light wind or downwind swell riding option.

MrFish
156 posts
13 May 2024 12:52PM
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Rail chines, and sharpness make a big difference to how the board "floats" in the water too.

ZeeGerman
280 posts
14 May 2024 12:52AM
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I can't speak from personal experience when it comes to small boards and have been happy with a +-0 boardsize so far.
Sometimes I'm tempted to go smaller but what holds me back is that quite a few sailors form the top tier across different riding styles sail going bigger than one would expect.
According to their own words:
Balz M?ller, mostly on 58 liters sometimes bigger, never smaller. I've never seen him on anything but his 58.
Robby Naish, mostly on a 75, almost his body weight.
Malo Guenole, always on a 65 at 75 kilos (he posted this on Instagramm only a few days ago)

They all seem to value the peace of mind it gives them in dropping winds or when shlogging out through the waves.

This isn't to say smaller boards can't be fun.

Velocicraptor
619 posts
14 May 2024 1:55AM
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ZeeGerman said..

They all seem to value the peace of mind it gives them in dropping winds or when shlogging out through the waves.



No chance that is their reasoning. Balz and Malo are at the pinnacle of the sport. They aren't sacrificing performance for safety.

More likely its because you can pop back onto foil faster, and transition to a combo if you aren't sinking the board on a landing.

Their reasoning behind board volume is not going to be relevant for 99% of the population.

NicoDC
206 posts
14 May 2024 2:48AM
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Velocicraptor said..

ZeeGerman said..

They all seem to value the peace of mind it gives them in dropping winds or when shlogging out through the waves.




No chance that is their reasoning. Balz and Malo are at the pinnacle of the sport. They aren't sacrificing performance for safety.

More likely its because you can pop back onto foil faster, and transition to a combo if you aren't sinking the board on a landing.

Their reasoning behind board volume is not going to be relevant for 99% of the population.


See, they don't sacrifice performance because they understand the highest performance comes from mastering, i.e. using the same gear as much as possible in the variety of competitions they will enter (which of course includes lighter winds).

ZeeGerman
280 posts
15 May 2024 3:16AM
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Velocicraptor said..

ZeeGerman said..

They all seem to value the peace of mind it gives them in dropping winds or when shlogging out through the waves.




No chance that is their reasoning. Balz and Malo are at the pinnacle of the sport. They aren't sacrificing performance for safety.

More likely its because you can pop back onto foil faster, and transition to a combo if you aren't sinking the board on a landing.

Their reasoning behind board volume is not going to be relevant for 99% of the population.


You're right when it comes to Malo, he actually makes the claim that popping back on the foil is made easier by his 65 Stunt.
Robby is clearly not at the pinnacle of the sport but still a very impressive sailor also on the wing. He outlined that exactly the peace of mind is what he's after, I seem to remember that he was talking about a day out in Pipelines with noone around on a marginal day with massive swell. surfing in is what you're after, but getting out without being mauled by the waves is essential for this.
I don't know if you have met Balz in person. He seems to see the biggest advantage that you can have performancewise in TOW as this is what enabls you to improve. As professional as he is in his ambition to develop the sport to its best, he keeps a very low profile when travelling Europe. His vans have always been too small for the task and although he is willing to sacrifice most of the space for gear, his quiver is pretty minimalistic for a pro. Not surprising for a family father travelling with wife and kids in a makeshift van. In this respect his reasoning could be very relevant for most of us albeit we would need to adapt it a little.
All it means to me is one shouldn't feel stupid if your gear is bigger than that of others. What counts is what you make from it.

kdrak
2 posts
Friday , 6 Sep 2024 5:50PM
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Very interesting topic !!!!

Someone using a -5 liters board to describe how he/she starts and how is difficult it is in choppy ? How much the board is submerged ?

RAF142134
343 posts
Friday , 6 Sep 2024 9:22PM
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As ZeeGerman says, Im 65kgs and my board is 65l, so it sinks a little more with full winter gear, but at +/- 0 it means I can ride very light wind on my knees or paddle back when all the wind decides to leave us stranded, when theres wind its a blast, it can be funny in chop but you do get better as the seasons pass, and the board fits neatly behind my sofa which I think is the most important factor to consider with board volume ;)

JohnnyDepp
38 posts
Saturday , 7 Sep 2024 12:09AM
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75 kg (78 in gear)
80 ltr (+5) for 6..12 knots (7 & 5.5 mtr wing)
-15 ltr for 13..35 knots (5 & 4 mtr wings mainly)

riding 2 year old boards, so far avoided the DW / mid length board craze :-)

kitebored
NSW, 561 posts
Saturday , 7 Sep 2024 7:29AM
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ninjatuna said..

I have a friend that just picked up a used board for towing around 35-40 liters. I want to try that on a good day with the wing. Have read in the past to about half your weight in liters is easier than just going like 10-25 liter below your weight. So if that works out, than I may have a 40 liter board in my future.



@ninjatuna - did you have ago on the half weight in litres board, any feedback?!



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"Basics: Board Volume" started by SpokeyDoke