This Stand Up Paddleboard is a beautiful thing that can be built lighter than the majority of SUPs. It is based on fast travel with much less effort on Lakes and Rivers by leveraging the best of Kayak and Rowing Skiff design.
It also behaves nice at sea, but is not designed for surf riding – less drag at paddling speeds is always working in your favour. Catching lake and offshore waves is fine … and a recommended fun activity!
I’ve had a couple of requests to make more plywood SUPS as interior decorations from people who have fallen in love with the look. A nice aspect from this new design from storerboatplans.com
But we will stick with boards that are meant to be used!
Our prototype build took two and a half weeks to build – weekends off to go sailing and a two weeks away in Cebu to help organise and run a 11 boat Oz Goose sailboat build. I have posted the slideshow of the full build of the Taal SUP here.
Buy Plans for the Stand Up Paddleboard
Buy Plans from our agents here for $80. Board is from 3 sheets of 3mm (1/8″) plywood, 4 to 6 litres of epoxy (1 to 1.5 US gallons and some rather small pieces of framing timber.
- Length – 12ft 6 inches
- Beam – 30 inches
- Weight – Developing countries – 12 to 14kg (likely with available materials)
- Weight – Developed countries – 8 to 11 kg (normal with quality materials)
- Crew capacity – 170 to 230lbs is normal. More is very likely to be OK looking at the way the prototype sits in the water. There is sufficient bow overhang and the stern shape is likely to produce much less drag than conventional boards with extra weight. For very big people it might be quite possible to scale it all up very slightly. A 5% increase in linear dimensions gives another 30lbs. A 7% increase gives 45 pounds (275) and still is in the normal width range but if ever raced will have to be in Open Class. I can provide
drawings modified this way at modest cost
Why are most SUPS shaped like surfboards – is it a correct choice?
As a designer, I asked myself “why is a surfboard shape considered as the most common shape for a Stand Up Paddleboard”.
The surfboard shape has an advantage of being very stable in general and has predictable handling in surf waves.
But looking at how SUPs are really used, mostly in flat water or going places on the ocean, their primary purpose is about as far from riding breaking waves as one can imagine.
RULE 1 – if you want to go surfing – use a surfboard shape.
The downside of the surfboard shape is that it is about the opposite of what we know are nice shapes for covering distance easily at speed. They are also about the worst shape for handling waves when lake, river or ocean water gets rough. Which is why racing boards are quite different shapes.
My idea was to make the board efficient like the racing boards but retain beginner board level stability.
Are Kayak or Rowboat shapes a better fit for real SUP use patterns?
The big advantage of rowboats and kayaks is that there are three numbers critical to performance over distance.
- Prismatic coefficient – is the measure of how much volume is in the ends of the boat relative to the middle.It is critical for design as every speed has a well documented prismatic coefficient that matches that speed. It is the main source of drag at faster speeds. If the board has to be paddled hard to match the boards around it or makes you weary heading a medium distance upwind in light winds, it is probably the Prismatic Coefficient that is out.It defines how the waves around the board are developed as it moves. Wrong Coefficient and the board wastes energy by making bigger waves and wake as it moves.Good Rowboats and kayaks are developed around that number. Racing Stand Up Paddleboards use those numbers too, but sacrifice stability by being narrow at the front and back.Pop a beginner SUP user on a racing board and its going to be more fun for the observers than the test pilot.I was very interested to see if there was a solution. Correct prismatic and nice stability.
- Wetted surface – is the amount of board surface in contact with the water.It is the main cause of drag at low speed, which is why the surfboard shapes feels less responsive and don’t accelerate very well from lower speeds as the more refined shapes.It adds significant drag right through the speed range, just less in proportion as the wave and wake drag get larger at higher speeds.Fast Kayaks and Rowboats, and the more refined SUPS also they reduce wetted surface but this also means narrow ends, so they sacrifice stability at the altar of Wetted Surface as well.My question – is there another way?
- Length – most people have some sort of instinctive idea that boat (or board) length relates to speed.How it works is any set of waves on the water surface have a set speed relative to the distance between the wave peaks. This is an unalterable scientific fact. The longer the distance between the wave peaks, the faster the waves will be going.So any type of boat will have its speed defined by its length. Unless the basic shape is silly, a 12.5ft board will be faster than a 10.5 board and a 14ft board will be faster than either.When moving quickly it will have a wave peak at the front (bow wave) and then the second wave behind that will be at the right distance for the speed. And so on behind that.As you go faster, the second wave peak increases its distance from the bow wave.When the second wave peak gets toward the back of the boat/board it means that the wave peaks are at the front and back of the board and the wave trough is between them. The board has, in effect sunk down because the water is lower around the middle of the board that provides most of the flotation – and that degree of sinking is what the prismatic coefficient attempts to control.So as far as the water goes it is important to show the longest possible length to the water.Here we have almost the full length of the board as the front is almost vertical and the tip of the back of the board just touches the surface.Make the best of the length that you have. Not possible with a surfboard shaped board that loses a lot of length at the front end. Which is why more performance oriented boards have a pointer front.
The photo below shows the Taal board moving along at cruising speed. It is quickly overtaking the sailboat I am in which is travelling at 2.5knots in the light wind, the board. Note that there is little wake and few waves around the board. Note the narrow vee shape of the wake at the back of the board – a big energy saving as the transom just kisses the water.
A note on concept of Speed for Stand Up Paddleboards and other human powered boats
Outright speed is for bragging rights. A big strong person paddling hard can keep the board going fast so it matches its prismatic coefficient and win races.
For most of us we just want to cover as much ground as possible without getting too tired. So this means a slightly different approach from boats designed around maximum speed.
A slightly lower prismatic coefficient consistent with a good steady cruising speed. Then let the numbers do their job to keep the bord going faster than a surfboard shape.
We also want the board/boat to be stable enough and easy to handle. If it can be pretty as well … that is a bonus.
Advantages of throwing away the need to surf at the beach – A much nicer board for distance paddling.
The first thing we threw out was the requirement for surfing waves at the beach.
This allows us to apply lessons from good rowing boats which are generally terrible in breaking surf. They are good with river and lake sized waves though – upwind and down.
The width that gives stability is moved above the water. Providing sharp lines for easy speed for distance work without the wobbles.
Here is a Whitehall type which were originally designed as a boat to hire for a few hours on the water, but many other rowboats such as whaleboats and gigs also have a similar cheat to get the numbers to go fast but be stable.
And here is our solution. Just the same idea, for exactly the same reason – easy fast cruising speed and stability when the board starts to heel.
With a range of weights aboard the bottom corner of the transom just touches or slightly immerses leaving a clean wake pattern. A clean wake implies little lost energy. Look behind the wide and flat stern of a normal Paddleboard and you see swirls and whorls in the water for the width of the board back – all lost energy that could be moving the board forward.
Advantages of throwing away the minimum weight requirement – towards the really light SUP
Everyone likes light things! The reason that most affordable SUPs are heavy is that they are built around a couple of hundred litres of foam. Foam dents easily, so then it has to be protected by thick skins. Fibreglass and plastic are not particularly light either.
The most highly developed home built plywood boats are the Moth Dinghies of Australia and the UK. They were able to achieve weights much less than carbon fibre can achieve and handle loads that far exceed anything a SUP would ever see. Here is one of the World Champions in Action.
Moths, at the peak of their development in plywood came in at around 17kg (38lbs) for a boat both double the width and double the thickness of a SUP.
Roll on toward a 6kg board at a fraction of a carbon board cost.
The plans cover a
- Standard build to aim at a board between 10 and 14kg.
- Methods to reach weights of around 8kg or less with good durability. These would require sourcing lighter ply and lighter timber and a bunch of building strategies to eliminate sources of failure as used by the much bigger and stronger Moth Dinghies.
In the Philippines, where we built the prototype, there are only heavier hardwood timbers and heavier hardwood ply. But the prototype is about the same weight as standard boards a couple of feet shorter. Everything is a tiny scale making the work great fun – effort is light. All the frames can be cut with a stanley knife/box cutter. All the panels are held together with cable ties because the stresses are quite low.
In Western countries, built of 3mm gaboon plywood and using lighter softwoods like cedar, fir, some of the lighter pines or the lightest and coolest of them all – Paulownia it should be easy to achieve sub 10kg weights. If you want to try these methods please contact me with the results and I will record them in a database for following builders to reference. We did the same with parts of my other designs and saw some of the weights tumble over time.
OK … building a super lightweight board might be frowned on in racing events because of the minimum weights set by manufacturers, but
1/ they will all be secretly jealous of your light board
2/ you will remember the light weight every time you load and unload your board and carry it down to the water.
3/ if you pretend to be struggling with the weight they might never realise your board is so much lighter 😛
The “Perfect Storm” that led to this design came from different directions.
- There is a SUP school running in the same place we teach sailing. I saw how people immediately fall in love with the idea of standing while paddling. It’s hard to know why, but it is true.
- I’ve become friends with the local SUP instructor as some groups like to sail and SUP in the one day. So there was a ready source of technical information plus
- I have the idea that lightweight structures often end up being the cheapest to make. Three sheets of thin plywood and tiny framing. I’m very influenced by Moth scows.
- These light structures are also fun to build
- I had three sheets of 3mm marine ply from the sadly closed Tuffply a very nice thickness.
- I designed a racing windsurfer using similar structures a couple of decades ago and produced a board about 3kg (6.5lbs) lighter than the carbon fibre production boards of the time – it lasted a racing career spanning a decade before being burned in a bushfire. Most of the carbon production boards from Mistral and others would have dents in the deck after a few weeks of racing.
The Following is a based on along thread on my Storer Boat Plans Group on Facebook
Structure is based on Moth structures circa 1980 but ply is much thicker (3mm rather than the 1.5mm moths, so structure is very robust).
I built a raceboard (long racing windsurfer with centreboard this way at Duck Flat. And it came in at 12kg (29lbs) compared to the somewhat delicate carbon/foam production boards of the time at 15kg.
Goes to show that air is the lightest core!
That raceboard had an honourable racing life of half a decade before it was burned in a bushfire.
Michael Marusic – Looks very thick, will be interesting to see this finished
150mm to from bottom to crown of deck. Because of bottom curvature (laterally) and the rounding of the rails a foam board looks a lot thinner. With a flat bottom and flat sides you can see all the thickness that is there. Possibly means a bit more stability (If it doesn’t push the paddler too high) because of the volume at the edges.
Paul Hayslett – Been thinking that Kathi and I could use a couple of these but didn’t want to spend the cash. I will buy these plans when they are ready.
Michael Marusic – How thick is the ply that you’re using? What’s the minimum you could get away with? Also, how much are you thinking of selling the plans for?
The board as is all 3mm ply. To really push it internals, sides and bottom could be down to 1.5. Deck in 3mm gaboon with glass under the ply in walk area.
One of several essential tricks when using such thin ply for an even lighter version is to do the bottom with ply sheets transverse. Means two veneers cross the bottom and stringers take the longitudinal loads.
One fun thing is that deck clamps and other cleats are all 8 x 8mm. Stringers are 22 x 8
More like model aircraft building.
Tono dropped around this morning. I had a hand hole planned. But he told me the good news that asymmetrical placement works best as it covers the ergonomics of different sized people. This is perfect as we can use the off centre web as one side of the hand hole. No change to the existing structure. Just glue a box in place and cut a deck hole later
We would expand it all around for larger people – we can do that at very modest cost.
Basically it is hitting the technical numbers (prismatic coefficient – a measure of the amount of bouyancy in the ends compared to the middle – most sups would be really out on this measure) around where a good rowboat would for normal cruising speed. So it is optimised for non surfing – just getting to where it has to go.
It has quite a bit less wetted surface because the corners of the board are out of the water. The racing boards basically do this too … but they do it by cutting away the corners. Here we lift them out of the water for a good prismatic coefficient for the likely cruising speeds and a reduction of wetted surface.
But we don’t get rid of the corners. That’s what we would do with a racing board, but as the geese show, the corners make a really big difference to stability – and by moving them up they will be there when the board heels. As the board heels they will meet the water and increase stability. This board will feel a bit more tender at small angles of heel but will still be able to push back on the foot with the highest pressure to much greater angles of heel – so a wobble might be more likely to be recovered – but that is one of the things we will find out by building one.
Anything this flat will catch waves. It might be swings and roundabouts – it probably will be a little faster when not wave riding for the same effort and that slightly higher travelling speed might make it catch a few more waves. When surging a bit on smaller waves i would not expect much difference in ability to stay on the wave. But where the board is really catching and running for distance on the waves it will have a slower top speed.
But maybe by catching more waves it will make up for it ????
it is also possible that the chine might produce a bit of extra drag and counteract all the good ideas (haha) above.
We are going to build it completely out of 3mm ply – normally I would like to do the deck out of 4mm, but it is not available here. We will put some glass under the walk area to prevent people putting their feet through – which we would do with the 4mm anyhow. The rest of the deck won’t be so well supported, but it will be strong enough for any normal contact. The glass will extend over the area with the more numerous frames (see in the three view where they will be – dark lines in all three views) and we will put a bunch of stringers where the frames are doubled too – under deck – maybe 24 x 8mm (we know that size works from moths).
Also we can get a standard weight for the build and if anything breaks, just beef that are up a bit – this is the lightest way to build boats. If it is under the 9kg class minimum I don’t care. People like light things and only few will race them or they can adjust the weight in the build
Bottom will be epoxy filleted together. Deck will be glued to tiny framing – moth sizes again.
There will be a bit of deck crown (curvature) just to make it look a bit rounder.
I was thinking of angling the transom forward and narrowing the transom a bit more … but this is meant to be a simple build. So we will keep it that way – at least for the moment.
I think maybe there is a loophole in the rule about “displacement” boards. If it is like the sailboard rule it is not at all objective as there is no such classification in science. Boards and boats form a continuum and there are no hard lines dividing “planing” from “displacing”. I think the powers that be would see the flat conventional bottom section in the middle and feel it is not a member of the “displacement” idea of shape in their heads. But the idea is much more like a rowboat which is a truer idea of displacement – rather than the “rounded” shape they think displacement means.
It is all a series of poor understanding of proven theory that allows the concepts to be so poorly articulated and understood. If I am right on this, and board paddles nicely (no guarantee 🙂 ) it might be interesting to develop the ideas toward a more racing angle later.
Some risks can be taken on the structure. For example the missing bulkheads in the no stand areas. Everything else is pretty conservative based on previous experience.
Any experimentation on increasing strength is an intellectual dead end. If the previous structure was adequate, a stronger or heavier one will also be OK.
The real learning comes with making things lighter – then there is a test and a progression based on an accumulation of data.
I didn’t get it either, paddling position and windage. But quite a few people I really respect do like it very much.At the Ta’al Lake conservation centre we teach sailing in the oz geese. We work alongside filisup who teaches and runs SUP tours.It’s really interesting to see how easily people approach using the SUPs. It’s fun and a bit crazy, provides great vewpoint for the tours and is a little harder than it looks.Unexpected is that a reasonable number of people coming for SUPs end up doing sailing lessons too.Fad or not it’s an easy entry point, people have fun, then look to extend their boating activities.planed down to the curvature required
The templates I use are sections of a circle, so any part of the template will work anywhere without having to worry about lining up a centreline.Hard to draw in a workshop because the radii are so huge. Trivial to draw up and dimension in CAD and provide a drawing for a quick to make template
Simon Lew – Really cool and unusual looking transom for a paddle board. Very curious to see how it goes.
It is like a pintail as far as the water goes. But will give stability when heeled – enough for beginners who have had just a couple of hours on more stable boards.
And it is what it needs to get the prismatic coefficient to reduce drag at the planned speed – 3 to 4 knots.
Should footsteer at lowish speeds too. Whether that is a bonus or a negative, we will find out.
I’d express it a different way. I’ve gone all out with primary and secondary stability using principles of good rowboats which operate at the same speed range and repeating their low drag hullform as much as one can in something this flat. It has been an interesting experience to try and hit the right numbers and interesting how the shape ends up being a bit unconventional – if you are thinking surfboards. But if thinking traditional rowboats it is all kindof obvious. the board.
Admission from the designer
Admission time – I’ve had plan writer’s block for some time.
Happily the plan for the SUP has broken that. I’ve done most of the plan in the last week. Just getting ready (metaphorically) to put the deck on. I have no problems doing the boat, but writing up the documentation to tell people what to do to put it together in a comprehensible way is tricky.
Very happy I conquered this plan in record time.
For those who don’t know Ta’al Lake is where I sail usually. it is the large caldera of an active volcano. Most of the data that allows the modelling of pyroclastic flow and surge was gathered in the ’60s from this volcano.
It is not the simplest of boats but not excessive and the plans cover the step by step but it really does touch on a large number of boatbuilding methods. Half is quite modern in construction, but the deck and subdeck is quite traditional. It took Job Ferranco 2 1/2 weeks to build
So a great choice to introduce people to a wide range of boatbuilding methods at quite low cost.hould I wait to buy and download until I’m ready to build? Will you incorporate feedback into the plans or just post on the wiki
Is building this boat different?
Plans are for people with some boatbuilding experience – building a plywood boat with epoxy will equip you with the methods.
This is not one of my step by step plans that explain every building step.
They assume some knowledge and experience
- This boat MUST use epoxy. It is a higher specification build and Stitch and glue method that pushes materials closer to their limit than normal boat structures. Alternative glues will not cut it and are a substantial risk – forget Gorilla glue, Titebond, PL-Premium – only epoxy to be used. Polyester resin must not be used at any stage – it doesn’t stick to timber adequately for reliable failsafe strength.
- This boat must use good quality materials. Builders will know that using low quality materials in a particularly sophisticated construction is folly.
- Builders will know that cleaning up as you go saves bucketloads of sanding later.
- Builders must know how to setup the next phase of work with locations and any clamping worked out in advance by doing a dry run to make sure everything is organised BEFORE mixing epoxy. This means that epoxy can be quickly spread over the laid out surfaces and not left to heat up and go hot in a container.
- Builders must be able to use fibreglass cloth and tape and keep surfaces smooth without adding too much resin.
- Builders must be self disciplined to keep weight out of the boat at every building stage. Heavy boats happen because builders decide that extra weight is warranted, usually for nebulous reasons or because they want to do something with extra epoxy. If building lightweight boats like this project, the best place for extra weight is the trash bin. Remember this at every stage.