High Performance SUP Foil Boards – Next Level

High-Performance Machines Are Light. Just like race cars, road bikes, surfboards . . . . High-Performance foil boards should be LIGHT.

When people suggest that “foiling” is 50% or 60% to where it is headed, I have to disagree. Foil Aspect Ratios are just reaching 11, or maybe 13, where performance gliders have Aspect Ratios of 30. The boards also have a LONG way to go with regards to construction technology, efficiency, shape and weight. Boards today (Nov 2023) have changing tails, lengths, up to 9’+, widths down to 16”. . . and it is still a game of excess pounds and kilograms, not ounces or grams.

Examples of this include home-built foil boards that are 30% to 50% lighter than production equipment.
My first board built was 7’ 9” x 6” x 21” @ 128 Liters and weighs 10.5 lbs after 150 sessions.

Here is a table I built comparing the HL Factor (Hectoliter Factor: Weight in lbs. per 100 liters) of my first 2 home-built boards vs. production equipment. 1) Sailfish, 2) Bumblebee. The HL Factor normalizes for the volume of the board. I intended to make my first board (The Sailfish) the lightest in the world from an HL Factor perspective. I used XPS foam, an intentionally porous lamination layer, forecasted all lamination weights and measured every input and layup final weight.

People predicted box failure, delamination, board flex, water absorption and rapid decay amongst other horrors. 150 sessions later the board is still closer to 10 lbs. than 11. It is my Goto for small waves, crowded conditions, or downwind SUP foiling. It was born in February, 2023 and pushed to the limits in and around Pillar Point (Mavericks) in Northern California, Downwinding in the Ocean, and San Francisco Bay with winds ranging from 20 to 60 mph. The boxes are holding, the deck solid. There ARE a few holes in the rails and dings here and there (I stuck my toe through the nose), but because it is made out of XPS foam the dings do not matter.

Hopefully this motivates:

  1. Manufacturers to make high (er) performance boards and
  2. You all to push the limits to go even lighter and share how you did it.

1 Like

Lessons learned from home-built board building:

• A High-Performance board should be 10 lbs. per 100 liters. HL Factor = 10. This means a 100 Liter board weighs 10 lbs., a 120-liter board should weigh 12 lbs or less . . .
• The entire board building is a mathematical exercise. A combination of surface area, volume, fiber and resin ratios all of which can be predicted ahead of time to within 5%. Meaning a 10 lbs estimate should come within ½ pound in final build weight.
• High Performance, light boards PUMP BETTER. Last year I was lucky to get a 2 for 1, my best this summer was 8 successive waves in one ride (see below). Axis 1300, 375P tail, over 50 years and 85+ Kg. Old guys need every advantage we can get.
• High Performance boards should NOT be bombproof. Bombproof is for Beginners
• Carbon is OK for flat sections, but it cracks on rails and adds unnecessary weight to nose and tail
• High Performance boards should be kept in a board bag, they do not do well in the back of a pickup truck with other boards, foils and power drills bouncing around.
• High Performance boards may not last forever. BUT with the speed of evolutionary design change this may not matter.
• Lighter boards have lower “Ding weight” meaning if you swing it around in the garage and bang a pole there is less weight and no candy shell to crack, the board may bounce like a bumble.

Heavy boards are a function of:
o Making the board look pretty: Paint adds 2 – 5 lbs of weight think Designer Watch vs. Timex
o Poor manufacturing techniques and/or quality control
o Over Investment in (the wrong) infrastructure
o Ding prevention on land


I was initially motivated to make light boards when the prone guys were doing circles around me 2 summers ago. Not willing to concede I figured weight and length mattered. I then read a post about a guy in the Gorge that bought a custom Kalama downwind board ~ 105 liters that weighed 6 lbs!!! I went to town trying to figure out how this would be possible aka EPS core, super thin lamination . . . and maybe, just maybe it would be possible.

Then I contacted the guy and he said “Oh no when I re-weighed the board it was more like 10 lbs.” By then I had figured out all the math thought ‘Wow I just got a free 4 lbs of leeway.’ So I went with XPS, waterproof foam, thinly laminated ends to keep the foam from flaking off and built what I thought might be a disposable test shape.

2 Oceans,150 sessions, 300+ hours on foil, 307 miles later I just added a new tail shape.

Here is the Sailfish in action in Rhode Island this past summer.

1 Like

Beasho, I’ve seen a lot of this on other forums from you, and for sure you unlocked a dream in many people to push the limits of light weight long skinny supfoils.

I personally think the hectoliter factor is an interesting metric, but board weight scales differently with volume vs. surface area (foam vs. lamination). I think the major change over the years from wide short “door shaped” boards to long skinny “canoe shaped” boards has unlocked the ability to focus on different construction techniques.

I owned a hollow carbon windsurfing board that was incredibly light more than 15 years ago. It was rumored to be custom built for a famous racer and painted to look like a production board, but I could never trace its history or find out how it was built. I didn’t want to cut it up and eventually sold it as the shape wasn’t working for me.

A few years back I became aware of the Patrik hollow windsurf foil board

I did some math, and I honestly think a 3kg 115L long skinny board is likely possible with the right tooling. It would be expensive as hell. I figure an 8’ x 19" 115L board has about 2sq-m of surface area. Nomex honeycomb could come in at 500grams per sq-m, for a total of 1kg. A layer of carbon can be 200-250g/sqm and we need no less than 4sq-m plus reinforcement - call it 6sq-m for a total of 1.2-1.5kg. Really lightweight foil boxes and installation plus vent arrangement would bring us to 3kg total.

Everything would be laid up with prepreg all in one-shot in a female mold and autoclave oven curing, but this is done for high performance boat building - probably someone who makes super high performance catamaran hulls could make this.

I think 3kg is probably the lower limit of the world’s technology today for a board like this. I dream about trying something like that…


You’ve achieved some impressive stats on your Sailfish! True comps I think should recognize the impact of leash plugs/traction (in addition to approach), and exclude the smallest boards (80L-110L).

I am curious though why the the production XPS boards feel so heavy … picked up an AppleTree XPS wing board the other day and was surprised by its heft. Is it the worst case scenario to do a tradition lam schedule on a heavier XPS blank, vs. embracing a truly alternative approach?

I picked up a 100L the other day that I think followed much of the hmb board-building approach, and was blown away by it’s weight … something like 8.5lbs, I couldn’t believe it!!! Definitely the kinda board that you have to paddle carefully on, but hey, the results are there.

1 Like

Here is the flying Dutchman talking about target weight of boards. He works towards a 100 Liter Board = 10 lbs. HL Factor = 10. That’s where “shooting PAR” comes from.

Larger boards should have an advantage from a lower percentage of TRACK weight and Cassette area reinforcement. So the HL Factor can be below <10 (e.g. 8 or 9). He is also referring to wing boards which are generally built tougher than we need for downwind boards. So achieving a lighter downwind shape should be feasible.

He also cites heavier boards resulting from ‘poorer’ construction methodologies.

Yes! There is a crew here in Half Moon Bay, CA that are building boards. Kyle sponsors the “Shape Shack” with a shipping container converted into a board building factory. Josh is the artisan builder. If you saw one of the “HMB” P3 boards (P3 = Pillar Point Productions) that was that light it was probably Arron’s board. I think it ended up 95 liters (6’ 11" x 16.5" x 6.75") in the 9 lbs range with EPS core.

I bought Kyle and Josh this scale, the most important piece of board building equipment. We/they Weigh Everything! They were hand laminating boards that were coming out 15 - 16 lbs @ 110 liters.

Then started using Vacuum bagging, postal scales, and gram scales for weighing Epoxy ingredients and ratios. They are building with Divinycell decks, 2 x 1" x 38" Divinycell Vertical Stringers, EPS core boards ~ 115 liters in the 12 lbs range. Kyle’s latest may be 11 lbs.

As a group we are generally sour on Carbon, with the exception of FLAT deck areas and flat patches around tracks. Otherwise Carbon is too heavy. Huge advocates for S-Glass. You could probably just use S-Glass and be fine. I am sticking with my XPS ugly duckling builds, they are advocates of the EPS with waterproof shells that end up easier on the eyes.

They have built ~ 25 boards in the 7’ 6" x 21" x 110 liters → 8’ x 18" x 115 liters and few a big guy 8’ x 23" x 150 liters (weighed 14.5 lbs). I build in my garage.

1 Like

My garage factory build here. 2nd Board the Bumblebee 6’ 9" x 26" x 5" x 115 liters. 11 lbs with Strap. HL Factor = 9.6.

Designed for rougher conditions SUP foil and wing board.

P3 Shape Shack. Josh, Denton, Kyle.

1 Like

Yup- it was Aaron’s board i picked up- pretty cool!!

Great Post, I am thinking of building a DW board. my first 2 wingboards were XPS, Homedepot Pink formular 150, but pretty heavy compared to 1 lb EPS. What XPS are you using? where do you source it? Is it hollow? My wingboards take a beating, I used carbon on last two and they are very tough. Don’t need all that for a DW board.