Help With Downwind Board Dimensions

Hey Guys, I’m getting my first DW board and a bit paralyzed with analysis on dimensions atm.

The stock sizes are:
7’6” x 19.25” x 5.75” | 102 lt
7’11” x 19.75” x 6” | 120 lt

From what i’ve read and watched, I think my ideal size would be somewhere between these two at 170lbs. The boards are made to order so I can choose any volume and stick with the stock dimensions that produces or get custom dimensions.

Given these things cost a small fortune and there’s no used market in Canada, I would like a size that lasts me as I progress. What volume should I go with?

Should I bother with custom dimensions? I like the idea of a shorter board (closer to 7’) for transportation etc but I don’t know if its worth messing with.

Is there any downside to adding some thickness to get it a little shorter?

Yes, length is your friend. The longer the length, the more glide, the easier it will be to build speed. Go for the bigger one. Aim for +30 volume. More volume is easier. (until it becomes to heavy)

Check out stinger boards on facebook. They’re in Canada and my brother just got one and said it’s the easiest of the 3 boards he’s had so far.

4 Likes

Forgot to mention that Stinger is building it, great to hear!

2 Likes

Totally agree with what Hdip has said. +30 on your weight specially if you are on the lakes. If your just starting your DW journey you want to make it as easy as possible on your self not harder.

2 Likes

Alrighty, i’ll go either 110 or 115 litre. 5/4 suit and boots will put me at 80kg at least. Thanks guys.

2 Likes

Going 30 plus if you are 70kg will have a very different outcome than if you are 100kg.

With surfboard volumes we deal in ratios or factors. I would suggest based on my learning so far 1.4x your weight in kg will give you a fairly safe minimum to learn on.

3 Likes

Listen through to that to hear the sizes of boards that the top 3 used for SUP foil M2O this year. James is probably on the least liters over his weight. Edo is on the most and I think it was over +40. Can’t quite remember. Probably the fastest through the channel too. He also unofficially won Paddle Imua the week before and beat James to the finish. (the race permit was full and Edo couldn’t officially enter, so he did the run, but didn’t run up the beach)

Yes and they are still trying to work it out themselves and particularly after some being in denial until very recently on the use of barracuda style longer and skinnier designs. Probably much more value in listening to the older regular mortals with access to good gear that have toiled away and eventually achieved dw proficiency.

2 Likes

I have the Stinger Stealth in the 7’11" X 19 3/4", 120 L model. At 85 kg (in gear) it is almost 40 L above my weight.

Haven’t had any conditions for downwinding yet. Working on flat-water paddle ups.

The board is the “Cheat Code” for light wind winging. I can get way with smaller wings and foils. The board’s hull speed is often faster than the foils minimum lift speed.
Don’t worry about swing weight. The foil is far enough forward that the tail extension almost balances it out. It feels and rides like a much smaller board.

I have also winged on the Blue Swirl 7’9" X 18", 97 L board shown on Stinger Foils Instagram page with a Lift 110HAX in 10-12 knots with a 5.5m wing. There was just enough room for my size nine on the aft deck pad. The board was shocking fast to get up on the water but a touch unstable without any forward motion.

Cheers, Trev

2 Likes

I would say that the type of conditions you plan to use the DW board in could also influence your dimensions choices. Where I ride, there’s a 5-mile run that’s relatively clean and waist high (wind waves only) which is relatively easy on my 96 L Armstrong (72kg weight). But on the north side of my island, with wind against ebb we get chest-head high bumps that are pretty messy and chaotic, and I wish I had more volume and length. Sound like you know the conditions you’ll be riding in typically, though.

I have very little experience in the open water conditions of my spot. Only kiting and kite foiling until recently so It’ll take some exploring to figure out what i’m working with. I have a 7km bay run to my house that will be perfect if big enough. Otherwise i’ll head north to wide open lake superior which gets some serious bumps.

Can we get some pics?? I can’t decide on a color (and need something to look at for the next month and a half)

The Grey board on the Stinger Foils Insta sight is mine.

Cheers Trev

1 Like

Yeah…then I agree with prior responses–go long, higher-volume and set yourself up for success as you learn. It totally sucks to not be able to stay on your feet long enough to generate board speed before you fall…and with big bumps begging to be ridden all around! How do I know? :wink:

Watching this video and looking at the pretty extreme dims, (145L, or weight+50), I realised that weight+X to get volume only works if your weight is ~80kg. It makes far more sense to go as a factor (ie. volume/weight). I only need to go +35 to get the same proportional size.

I plotted the below as an attempt at a guide. My 95L board is definitely on the lower bound for me at 1.36 or +25L.

Find your weight on the left and then go along that row to find the various volumes.

Spreadsheet here. This presumes long narrow board, as it probably differs for wider boards. I spent more time on the pretty colours than the actual ratios, so would happily refine those numbers if anyone has any data or feedback? What size did you find diminishing returns on the large side, and too small on the small side?

1 Like

I am 85kg and ride an 18"w by 8’4" by 6"average. 108L. This puts me in “expert” range. I am no expert. I think that the foil and especially the mast length has a lot more to do with stability than the board. Shorter mast is way tippier than longer. Bigger chord like Axis 1300 is way more stable than high AR like 1201. I think of it like an anchor underneath. The bigger the area, the more secondary stability. That 18" width sure comes in handy when I start paddling. Narrow boards also require less of a j-stroke to go straight.

1 Like

Interesting. I suppose you will start looking at faster foils and then need a bigger board? I’ve ridden the 1300 extensively but then when going to a smaller foil (pp140) I didn’t notice it being any less stable. Have you managed to ride smaller faster foils with the same setup? Presume you’d still have a long mast so maybe minimal effect.

For my weight at 70kg a 95L (7’6x19) board puts me in Advanced, and I would probably suggest to someone new to go more volume as I find it a bit too easily submerged.

I tried the spitfire 900 for a sup foil with same board and it was quite a bit tippier. I think the chord of the mast prob plays a big role too. I do think that a wider board would be nice for sup foil as it can be bumpy and I am not always pointing the same way relative to the wind. I just built a 7’7" x 22" but haven’t ridden it yet. I will report back when I do.

1 Like

With boards sitting now between 8 and 9 ft in length by 17 ish, the discussion is moved to width, thickness and weight combination. Longer seems to allow to go narrower, maintaining stability. This table is great, but missing the other variables which are more important.

1 Like

I’ve generally assumed that most boards will be in the aspect ration of around 5 (see here for some examples of aspect ratio). 8’0x17 is ~5.6 AR. The table is presuming long and narrow, >5 AR

(ideally I could incorporate more nuance but as a simple guide it would fail on the simple aspect!)