At 225 lbs/ 102 kg I always feel like when ever I windsurf or windfoil on free ride gear there is just not enough float especially in light air. I also am not interested in super wide full blown race boards with 10 meter sails. So I designed and built this board to suit my needs for a one board windfoil quiver.

In sub foiling conditions this board it is super fun to cruise around on and even do light air free style as it feels like a long board in a way because of all the float. In marginal foiling weather, it shines with windward ability and early lift. In a breeze, it's short length and good balance make it nimble and easy to steer. I rode a low volume narrow tail board for a couple of years now and it made my feet fatigue and just wore me out. This board is so much more fun and easier in all conditions. Stay tuned for more reports and maybe a video.

Many thanks to David Ezzy for his input on the design.

Water Craft Design Custom Windfoil Board
Length: 6'6"/ 198 cm
Width: 34"/ 86 cm
Thickness: 4" / 10 cm
Volume: 177 liters
Construction: Carbon and Innegra over eps blank
Weight: 21.5 pounds / 9.75 kg
Program: Big Boy Freefoil in 8-30 knots
Sail size: 8^m to 4^m2

Designed in 3D using Rhino software









Blank

Off the shelf Gofoil Box modified for tracks




Ready for lami

Bottom bagged
Bottom lami ready for bag


Finished deck shape

Foot strap inserts

Test samples, scale and test hammer!

thats a beauty - probably silly question but is the is the vacuum bagging essential ?

did you hot wire/shape the blank yourself ?

The bagging is not essential but really helps with build quality and weight reduction. I was trying to get the shape fully cnc cut but it would not fit in the cutting envelope of the blank supplier I chose. The blank supplier either has a cnc hot wire or used cnc cut patterns to guide a hot wire that cut the top and side views for me. I had to glue the right and left half of the blank together and shape the radius at the deck edge. I also cut the recesses in the bottom manually.

Are tail recesses really needed on a foil board?

I like it too..
You did a nice job..
I wonder at which point does short length start being more of a hindrance for getting on the plane/fly?

"Construction: Carbon and Innegra over eps blank"
Over PVC?
No rail bevels.....no problems?

Select to expand quote

Is your board similar to what David Ezzy riding ? (below web showing his board)

Wow that looks great! So much volume in such a short board. Well done.

Looks good. That's one advantage of foil boards being able to pack a lot of volume into a small board with very little negative impact

www.instagram.com/p/B078v5jnUjd/?igshid=11ik435yi7voj

Here's one I made earlier :) 190 x 85 x 150 litres
And yes Yoyo- with the wide tails you do need cut outs

YoYo
Honestly I am not sure how much the cut outs matter. Intuitively I feel they help at lift off speeds and also when you are still moving fast but touch down slightly. Every PWA board has them. David Ezzy told me not to bother. I put them in any way for the look, after I ride the board enough to really have a feel for the performance I want to fill the cut outs in with light foam and glass and see if I notice the difference.

Tibi
Thanks for the props! Again I am not sure where the trade off is. I learn by dreaming, drawing, building, riding, breaking then taking notes and repeating. This is my first board design/build of any sort most of work has been in boats. I have learned that this shape works for me.

Te Hau
Thanks for asking , it is a good point. The laminate schedule is not what is typically recommended and until I test this further I do not recommend it. But it's my personal board and I can take chances if I want to and I will live with the sacrifices or successes. That is correct there is not any pvc core in between the skins. The foam is only 1lb/ft^3 eps which is really light. The base laminate is three layers of 2 oz. Innegra and two layers of 6 oz. carbon. There are many extra patches of Innegra in the areas exposed to rig impact as well as extra carbon patches in the high load areas. This is a laminate schedule with a lot more high end fibers in it than standard. So far it is holding up after a handful of sessions. My test samples held up well to the claw end of a hammer. The board feels stiff and rides really silent for a carbon board. I feel like there are still a lot of gains to be made in the area of laminate schedules and build processes.The lack of rail bevels and zero tuck to the rails was influenced by David Ezzy. The concept is to keep the rails sharp and full so the board will skip back off the water. The sharp rails release the water which aids in early take off and prevents the board sticking on unintended touch downs. I want to build and ride a SUP style board with big bevels next and see how the opposite concept rides! I 3D modeled a few beveled prone surf foil boards for my mates and they are loving the shapes. Time will tell!

SA_AL
David Ezzy is really friendly and helpful. I reached out to him for some info on his board and he sent me his CAD drawing and spent a bunch of time offering his input! When some like that offers their help I take it so yeah my board is very similar to his. He suggested the high volume given my weight and that is the main difference between our shapes, mine is a couple inches thicker. My board is 1.75 inches longer and the nose is a little fuller when viewed from above. In hind sight I would trim the length and nose width if I were to build this design again.

Windbot
Thanks mate!

DarrylG
Thanks! Your board looks sick! I love it! You are a pro! What are the dims, weight and construction? It looks like there are two subtle bevels to the bottom is that correct? How did it ride?

Thanks. Very interesting re the laminate schedule.
Yours gives 55gr/litre which is a pretty good ratio.
Like you, I build my own and so we can underbuild and then back off on the next if we run into trouble.
I have seen one builder in Germany who is down as low as 37gr/lit and I guess he's not using any PVC either.
I purposely overbuilt my Foiler (62gr/lit with 5mm PVC) in order to slow reactions down for learning and now I'm into Mk2, as light as I can get it.
Your info is much appreciated.
Nice job you have done and also Darryl.

Thoughts on just using PVC in the high impact areas? It's not like a regular board where constant impact is happening against the water I guess.
Although maybe vertical stringers to connect the foot positions, mast track and foil box?

How much rocker do we need?
Some info from a French build site

Foiler rocker lines
@1000 1200 1500 2000

AHD Thunderbolt 145l 4 10 30 110 mm

JP Hydro foil FWS 120L 5.5 16 43 150 mm

Naish Hover 142 2 4 15 65 mm

Slingshot Wizard 125l 1 5,5 23 nc

Taboo AIR RIDELTD81 145 0,5 5 22 100

Mykz Mk1 133L 1,8 6 23,5 94

JP Foiler 135 2,2 7 24,5 126,5

Exocet RF81 131L 2,5 8 22 84

Starboard H/sonic 105L 1,2 4 22 90

Fanatic Stingray 140 1 4 17 90

Te HauI
I like your metric of gr/ltr that is a smart way to track build weight across the size range. I am going to start tracking that number! I have attached dimensions of my rocker line. I was concerned about nose diving because of the short length and lack of nose rocker. This has not been an issue yet. It works because the rails are so thick and there is so much float. There is plenty of float to uphaul a big sail. With the big tail you can move back to the straps even at a standstill. Once you start moving and loading the sail you have to move back swiftly but It is easy to just step back to keep the nose up. The shape of the board forces the rider to get the weight over the foil where it is supposed to be, this is a really good design feature!

Grantmac
I am not sure foam at any density is the solution to impact resistance. I used Innegra to address impact loading. The fiber is supposedly the lightest fiber at the moment. It is designed to add energy absorption to a laminate stack. I have 3 layers of Innegra over the entire board and patches of it in areas the rig can hit the deck. Time will tell how good this works, if it holds up to my abuse I will turn this board lose on beginners! The ultimate test! Actually I think giving it to Balz Muller would be the ultimate test!

I did some googling on tail cutouts once, and found a Patrick raceboard where they put a tube going from the cutout inside corner to the deck, to relieve the suction created by the cutout.

The only slalom board I ever owned with tail cutouts, was slow to plane, but super fast. Just maybe tail cutouts are for top end only.

I left them out of the my foil board.

I could see tail cutouts helping the board pump though, in the way the tail bevel helps a SUP board pump.

The cut outs are probabbly in the nats ass catagory, in other words I am not sure it matters much.

Has anyone ever tried a steped hull like a power boat or seaplane hull? Might work well as a foilboard!???

You've got Innegra over the carbon? Do you run any stringers in the board?

I do think that foiling will have very different stresses from fin sailing and perhaps using the same construction techniques for both isn't productive. Are foiling SUPs running sandwich I wonder? The one DIY I saw locally definitely wasn't.

Grantmac
The Innegra is under the carbon. One of the cons of using Innegra is that if fuzzez up when you sand it. So that means you need to have some other cloth over the innegra. 4 oz glass works good but in this case I have carbon on top. There are no stringers in this board. I set a weight goal of 21 pounds and refused to add anything that would increase the weight more. So my test samples with core or stringers all came out too heavy and added little to no improvement to impact resistance. Yes some foiling SUPs are built with sandwich construction and some are not. I still maintain there is a lot of room to improve the construction of the boards we ride. The current products are extremly labor intensive to build and they are really fragile.

The construction raises a few interesting questions:
- do short foilboards not need a sandwich construction because hitting chop is no issue?
- does the Innegra layer provide better impact protection in catapults?
- does it make sense to put a brittle (carbon) layer on top of the Innegra?

Only time will tell. It will be interesting to hear how the board holds up over time, say 150 or 200 sessions.

A couple of questions:
- are you not using any EVA foot pads, or are they just hard to see?
- is the Innegra you are using just the polypropylene (Innegra S), or is it mixed with other fibers (Innegra H)? If it's mixed - with what?

I'll be interested to see how the carbon top layer works out. I'd think a 4oz glass would work better. But weight is definitely a factor.
This construction is definitely more friendly to the home builder.

What are the tailkicks you guys use? For a foil with a plate which is hard to trim on the rake, or someone who doesnt want to be bothered its one of the most important parts of the board.

Cutouts matter a great deal, in the sense that everything of the board that sticks to the water delays takeoff. A board with a narrow tail takes of earlier than a board with a wide tail. We need the latter for foiling (in general), so we have bigger cutouts to still minimize the sticking surface. Its quite noticable. Also reduces drag in touches when you have the rake trim right.

Select to expand quote

WhiteofHeart said..
What are the tailkicks you guys use? For a foil with a plate which is hard to trim on the rake, or someone who doesnt want to be bothered its one of the most important parts of the board.

Cutouts matter a great deal, in the sense that everything of the board that sticks to the water delays takeoff. A board with a narrow tail takes of earlier than a board with a wide tail. We need the latter for foiling (in general), so we have bigger cutouts to still minimize the sticking surface. Its quite noticable. Also reduces drag in touches when you have the rake trim right.

Would a person want shallow cutouts to maximize volume before the foil start lifting? I'm modifying a board right now which has extremely deep ones and I'm considering filling them in to some degree.

Select to expand quote

WhiteofHeart said..
What are the tailkicks you guys use? For a foil with a plate which is hard to trim on the rake, or someone who doesnt want to be bothered its one of the most important parts of the board.

Cutouts matter a great deal, in the sense that everything of the board that sticks to the water delays takeoff. A board with a narrow tail takes of earlier than a board with a wide tail. We need the latter for foiling (in general), so we have bigger cutouts to still minimize the sticking surface. Its quite noticable. Also reduces drag in touches when you have the rake trim right.

In my case, tailkick is 0. Rocker is 0 until 800mm, mast exactly square to hull. No cutouts, narrow tail, 570mm at 300. Mk2 is 675mm tail.

JP 135 has 3.2mm tail kick. 0 at 300 and until 700mm

Fanatic Stingray 140 has 0 kick and until 800mm

Select to expand quote

WhiteofHeart said..
What are the tailkicks you guys use? For a foil with a plate which is hard to trim on the rake, or someone who doesnt want to be bothered its one of the most important parts of the board.

Cutouts matter a great deal, in the sense that everything of the board that sticks to the water delays takeoff. A board with a narrow tail takes of earlier than a board with a wide tail. We need the latter for foiling (in general), so we have bigger cutouts to still minimize the sticking surface. Its quite noticable. Also reduces drag in touches when you have the rake trim right.

Not sure what you mean by tail kicks but I would like too.

I like that you pointed out that wetted surface = drag. I am really noticing it as ride this wide tail board more, way more drag than my narrow tail board. I am becoming more interested the design of cut outs!

What is the ideal rake? Intuitively I would think you want the cord of the main wing parallel to the bottom. I bet getting this right will help limit crashes from touch downs.

Select to expand quote

boardsurfr said..
The construction raises a few interesting questions:
- do short foilboards not need a sandwich construction because hitting chop is no issue?
- does the Innegra layer provide better impact protection in catapults?
- does it make sense to put a brittle (carbon) layer on top of the Innegra?

Only time will tell. It will be interesting to hear how the board holds up over time, say 150 or 200 sessions.

A couple of questions:
- are you not using any EVA foot pads, or are they just hard to see?
- is the Innegra you are using just the polypropylene (Innegra S), or is it mixed with other fibers (Innegra H)? If it's mixed - with what?

I think foil boards need to be as tough as or tougher than regular boards. I also think most boards are too fragile.

The Innegra does help with impact resistance. In fact I just got launched hard twice today (catapults) with no damage. I am using Innegra S. In my testing I noticed that alternating the fiber direction with each layer dramatically increased impact resistance.The manufacturer has a video online where they put the carbon in the middle of the stack and the Innegra on both sides. The problem in this application is that the Innegra really can't be sanded because it fuzzes up. I did not have room in weight budget for the extra glass on the outside so that is why I ended up with this solution. On my next go if I could save weight else where I would like to do it that way.

I do not have any eva foot pads. Again, my weight budget was depleted by the time foot pads would have been installed. I bought a roll of cork that I wanted to cover the deck aft of the mast with but it would weigh well over a pound. As a rule I always sail with booties so I will survive.

As an aside, I tried using the cork as a core in the laminate. At first glance it should be way heavier than pvc but the foam has more resin uptake so my samples ended weighing with in grams of each other. The cork samples were more impact resistant than the foam.

In the end all the cored options that I built and tested were too heavy to hit my weight goals so I did not use any.

I will keep y'all post as I get more sessions I am up to 6 as of today. Already I feel like I am out of the honeymoon faze with this new ride and ready to view it critically. I want to share the good, bad and ugly of what I learn along the way.

Do you think the cork would offer as much stiffness? It's an appealing material for the home builder plus environmentally friendly.

Select to expand quote

utcminusfour said..

WhiteofHeart said..
What are the tailkicks you guys use? For a foil with a plate which is hard to trim on the rake, or someone who doesnt want to be bothered its one of the most important parts of the board.

Cutouts matter a great deal, in the sense that everything of the board that sticks to the water delays takeoff. A board with a narrow tail takes of earlier than a board with a wide tail. We need the latter for foiling (in general), so we have bigger cutouts to still minimize the sticking surface. Its quite noticable. Also reduces drag in touches when you have the rake trim right.

Not sure what you mean by tail kicks but I would like too.

I like that you pointed out that wetted surface = drag. I am really noticing it as ride this wide tail board more, way more drag than my narrow tail board. I am becoming more interested the design of cut outs!

What is the ideal rake? Intuitively I would think you want the cord of the main wing parallel to the bottom. I bet getting this right will help limit crashes from touch downs.

Tail kick means tail rocker. In the case of the JP135 it is 3.2mm at the tail, 1.5mm at 100mm, 0.6mm at 200mm and zero at 300mm from the tail.
The fin box is at 163mm from tail so they have box/mast raked relative to the rocker flat which runs 300 to 700mm.
I guess the idea is to lift the front as the board takes off.
I am interested to hear 'White of Heart's' take on this subject.
As an aside, I recently measured a board which had the mast mounted so that the foil was running negative 2.2 degrees when the board was on the rocker flat. I imagine this was slow to take off and I wonder how many are like this. It pays to get the big builders square out and check this I reckon.

Select to expand quote

utcminusfour said..
At 225 lbs/ 102 kg I always feel like when ever I windsurf or windfoil on free ride gear there is just not enough float especially in light air. I also am not interested in super wide full blown race boards with 10 meter sails. So I designed and built this board to suit my needs for a one board windfoil quiver.

In sub foiling conditions this board it is super fun to cruise around on and even do light air free style as it feels like a long board in a way because of all the float. In marginal foiling weather, it shines with windward ability and early lift. In a breeze, it's short length and good balance make it nimble and easy to steer. I rode a low volume narrow tail board for a couple of years now and it made my feet fatigue and just wore me out. This board is so much more fun and easier in all conditions. Stay tuned for more reports and maybe a video.

Many thanks to David Ezzy for his input on the design.

Water Craft Design Custom Windfoil Board
Length: 6'6"/ 198 cm
Width: 34"/ 86 cm
Thickness: 4" / 10 cm
Volume: 177 liters
Construction: Carbon and Innegra over eps blank
Weight: 21.5 pounds / 9.75 kg
Program: Big Boy Freefoil in 8-30 knots
Sail size: 8^m to 4^m2

The non-pvc construction is interesting! I stopped building my own boards ages ago when composite came into the picture. The extra step, and skill required were just too much. Now might be the time to revisit the idea!

BTW: I have a Flikka custom 217x78 that I feel could use a few extra liters, I am 70 Kg and the board is 117 Liters.

Select to expand quote

Te Hau said..

utcminusfour said..

WhiteofHeart said..
What are the tailkicks you guys use? For a foil with a plate which is hard to trim on the rake, or someone who doesnt want to be bothered its one of the most important parts of the board.

Cutouts matter a great deal, in the sense that everything of the board that sticks to the water delays takeoff. A board with a narrow tail takes of earlier than a board with a wide tail. We need the latter for foiling (in general), so we have bigger cutouts to still minimize the sticking surface. Its quite noticable. Also reduces drag in touches when you have the rake trim right.

Not sure what you mean by tail kicks but I would like too.

I like that you pointed out that wetted surface = drag. I am really noticing it as ride this wide tail board more, way more drag than my narrow tail board. I am becoming more interested the design of cut outs!

What is the ideal rake? Intuitively I would think you want the cord of the main wing parallel to the bottom. I bet getting this right will help limit crashes from touch downs.

Tail kick means tail rocker. In the case of the JP135 it is 3.2mm at the tail, 1.5mm at 100mm, 0.6mm at 200mm and zero at 300mm from the tail.
The fin box is at 163mm from tail so they have box/mast raked relative to the rocker flat which runs 300 to 700mm.
I guess the idea is to lift the front as the board takes off.
I am interested to hear 'White of Heart's' take on this subject.
As an aside, I recently measured a board which had the mast mounted so that the foil was running negative 2.2 degrees when the board was on the rocker flat. I imagine this was slow to take off and I wonder how many are like this. It pays to get the big builders square out and check this I reckon.

Thanks Te Hau!
So the rocker on my board is dead flat from 0 mm to about 98 mm.

2.2 degrees would be very noticeably bow down in the air. That might make a lot of down force way far forward from windage. I bet it would feel sticky in touch downs too. I have heard the PWA riders talking about using the down force from the huge forward decks as way to get the upwind/downwind oriented set ups across the reaches.

What tools do you use to measure with? Smart phone with level app or???

I used a big square when I set the tuttle box in but all that ensured was that the leading edge of the mast was square to the bottom making the box square to the bottom. Good thing I knew better than to use my Horue for that job, that mast leans forward! I assumed the leading edge of my Mosses was meant to be plumb but never actually checked. So the fuse or more importantly the cord of the main wing may or may not be parallel to the rocker flat, if it is out it is not by much, I have not measured that but I would like to.

Select to expand quote

utcminusfour said..

Te Hau said..

utcminusfour said..

WhiteofHeart said..
What are the tailkicks you guys use? For a foil with a plate which is hard to trim on the rake, or someone who doesnt want to be bothered its one of the most important parts of the board.

Cutouts matter a great deal, in the sense that everything of the board that sticks to the water delays takeoff. A board with a narrow tail takes of earlier than a board with a wide tail. We need the latter for foiling (in general), so we have bigger cutouts to still minimize the sticking surface. Its quite noticable. Also reduces drag in touches when you have the rake trim right.

Not sure what you mean by tail kicks but I would like too.

I like that you pointed out that wetted surface = drag. I am really noticing it as ride this wide tail board more, way more drag than my narrow tail board. I am becoming more interested the design of cut outs!

What is the ideal rake? Intuitively I would think you want the cord of the main wing parallel to the bottom. I bet getting this right will help limit crashes from touch downs.

Tail kick means tail rocker. In the case of the JP135 it is 3.2mm at the tail, 1.5mm at 100mm, 0.6mm at 200mm and zero at 300mm from the tail.
The fin box is at 163mm from tail so they have box/mast raked relative to the rocker flat which runs 300 to 700mm.
I guess the idea is to lift the front as the board takes off.
I am interested to hear 'White of Heart's' take on this subject.
As an aside, I recently measured a board which had the mast mounted so that the foil was running negative 2.2 degrees when the board was on the rocker flat. I imagine this was slow to take off and I wonder how many are like this. It pays to get the big builders square out and check this I reckon.

Thanks Te Hau!
So the rocker on my board is dead flat from 0 mm to about 98 mm.

2.2 degrees would be very noticeably bow down in the air. That might make a lot of down force way far forward from windage. I bet it would feel sticky in touch downs too. I have heard the PWA riders talking about using the down force from the huge forward decks as way to get the upwind/downwind oriented set ups across the reaches.

What tools do you use to measure with? Smart phone with level app or???

I used a big square when I set the tuttle box in but all that ensured was that the leading edge of the mast was square to the bottom making the box square to the bottom. Good thing I knew better than to use my Horue for that job, that mast leans forward! I assumed the leading edge of my Mosses was meant to be plumb but never actually checked. So the fuse or more importantly the cord of the main wing may or may not be parallel to the rocker flat, if it is out it is not by much, I have not measured that but I would like to.

Old school measuring gear. A graduated milled alu channel section sitting on the rocker flat and drill bits as the gauge up to 8mm, also 0.5mm, 1.0mm, 2mm steel rules for the smalls and then them also for the bigger dimensions. Have measured lots in the past 20 years and have a good picture of development, copying etc. Very interesting.