Super Spuds R Us!

The World's Shortest Playboat:
Length: 4' 4" 132 cm
Width: 29" 74 cm
Volume: 62 gallons 234 litres
Weight: 18 lbs 8 kg

New! The Full Evolution:


Click here to go straight to the new Squd pics ...



This page is devoted to the design, construction and paddling of Super Spuds -- ultra-short homemade whitewater craft. They are paddled in the kneeling or C1 position and with a single-bladed paddle, although if you learn the correct roll, a kayak paddle can also be used.

Whitewater boat design has generally been getting shorter, from about 14 feet long in the 1980s to 9 foot as standard in the early 90s and then 7 foot boats becoming the norm in the late 90s. By 2002 there were several boats available that were in the 5'11" to 6'6" range.

I wanted to go one further, so taking it to the logical conclusion, I built a 4 foot boat. The implication of this is that you have to kneel as there is no room for your legs to stretch out. However, some of us like it that way! ;)

SuperSpuds are basically high tech coracles.

They are very light, no fuss or airbags or drainplugs required, you can keep one in your cupboard and carry it in the back seat of your car. It takes 2 seconds to hop in and be ready to launch -- no struggling with spray decks or backbands.

The SuperSpud In Action!


Access the smallest of features

With no fear of hitting the bottom!

Puts a smile on everyone's face...

Everyone and his dog wants to try ...

Bowstalls are easy

Jody in America has built his own prototype already, after the website has been up for just 4 days!

Duct tape as nothing will glue polystyrene ...

Design

Spud Spud Spud

The main problem is in making short and stubby curves look elegant , so I sought inspiration from other types of product, including the Jaguar XK180 which has some nice back end rocker, the Nokia 3210 mobile phone, which once squashed and stretched a bit, has a lovely form factor and a nice top deck curve. And the head shape of the Snowshoe Hare somehow helped inspire the bow rocker ...

The boat is a self-baling kneel-on-top. The hull is basically a flat planing surface, with friendly rounded corners. There is enough rocker for front and back ferrying/surfing, and the rounded front and back decks have pretty good resurfacing tendencies should pearling occur. The front has a bit more volume than the back for river running and to allow a forward lean when taking a stroke. C1 playboaters will know what I am on about here ;)

I was also looking for something that was nice and stable on end, which I partially achieved as it is lovely on the bow. Despite the thick cross section of the bow and stern, their short length means squirting and cartwheels are acessible too. I am not sure how it will endo / loop as the deck is very short which means it may not get much height, but then exactly because it is short it doesn't need much height to loop ...

Prototypes

Polystyrene is very cheap and very quick and easy to cut, but I found it impossible to glue so I held it together with duct tape (what else?) -- it lasted long enough for a proof of concept and a float test:
Spud Spud Spud Spud Spud

Note the swallowtail and zero stern rocker. In the end I chickened out of that as I thought it would catch while back surfing, so I rounded the stern instead. However, the swallowtail might have given a tad more speed, especially if you edge the boat while forward paddling ...

Paddling

The boat is incredibly stable and very confidence-boosting.

If you want to play, then you need a good C1 roll -- starting on the back deck, then sweeping forward and coming up on a low brace. Get your nose on the front deck when you finish the roll, and grip yourself in tightly, and it should be fine. If you bow stall when you come up, just claim it was an intentional Zero to Hero move!

IMPORTANT SAFETY NOTE: You don't have to use straps -- straps carry significant risk and should be used only if you are an experienced C1er. It is very possible to cut the knee and thigh channels to be sufficently snug for you to be able to roll and cartwheel with no strap and yet still stay in the boat ...

Update -- I have not been using straps at all -- and while my roll is only about 50% after 1 hour's practice, it is improving fast, which suggests it really is a technique thing -- grip up with your knees and toes to stop yourself falling out. No straps make the boat very simple and so easy to hop in and out of, and very accessible for beginners. In the shallow (waist deep) British rivers and artificial courses I paddle in, you can just hop in midstream after a swim. It may be possible to climb on in deep water, kicking your feet like mounting a surfboard, but I haven't managed it yet. Obviously, a roll is preferable every time, but the easy entry (and exit!) and the fact that you don't need to empty the boat means that swimming is much less of a big deal.

Deepwater self rescue is possible ...

As you would expect, it's a little slow. But because displacement hull speed is related to the square root of waterline length, then this boat at 4 foot is only 20% slower than a 7 foot boat like a Topo or BigEZ. (Try it: max hullspeed in knots = sqrt(waterlinelength in feet)) Then of course, there's speed on a wave, and with the huge planing area, it actually goes nicely! The planing area is about 900 sq. in. (compare that with 640 sq in. on a Liquid Logic Session Plus (the only other people who publish stats on planing area...)

It surfs small waves as well as my Delirious and an S8 C1 paddler thought it was comparable too -- exceptionally stable but slicing and flatspins are obviously not nearly as smooth.

My only disappointment with this version of the boat is that Ferry Gliding is hard hard work -- I had hoped to get a planing situation on ferrying, but it remains stubbornly in displacement mode and so needs plenty of work to attain.

For more power I found myself doing strokes that are not so much cross bow as 'pre bow', starting about 2 feet in front of the bow and then drawing towards your belly, with a slice out to the offside to finish. A feature that is probably unique to this boat.

The 'pre-bow' stroke

I had considered cutting down the bow volume, but I am glad I didn't -- C1 paddling has a large vocabulary of moves that involve leaning on the front deck: bracing, rolling, bow stalls, resurfacing from drops, etc. You can lean forward with impunity and indeed pleasure!

One person who tried the boat suggested adding more volume to the stern as well -- I will consider this, but the real problem that needs solving is stability when in the stern station, which I am not sure is just to do with volume, as other short boat paddlers (eg GForce) mention that the short stern makes stern stalls tricky.

Using a Kayak Paddle

Not everyone is used to using a canoe paddle, but don't be put off because a kayak paddle is completely workable with a SuperSpud. Just two points -- please don't use high braces as it will wrench your shoulder. Likewise, trying your old sweep roll, starting with your nose on the front deck, will result in a failed roll and probably hyperextension of the shoulder. You have been warned! Practice in the pool first! If you are using a kayak paddle, then use a back deck or steyr roll [link ChrisJ]

Make one yourself!

Super Spuds are home made from outfitting foam. The ideal foam is about 30 to 45 kg/m3 (2 to 3 lbs/ft3), with nice products being: MiniCel, Ethafoam 220, and Plastazote LD45. They come in sheets and if you can get it 3 or 4" thick, then you simply cut out your desired boat in 3 or 4 layers, and bond them together. This can be done with contact cement, but I found that they can be perfectly bonded using just a heat gun. However, I ended up using LD45 (Lovely stuff! Comes in many colours too! Made by Zotefoams) in a 90 mm thickness, which could not be folded back enough to get the heat gun between the layers, so I ended up gluing. I used Evode Evostik 528 Contact Cement 'Green Tin' (available in the UK from branches of Travis Perkins. In the US you want 'Red Can' [xxxx] ). Either method is very much adopted from the Hydrospeed riverboarding movement in France, so see this page on Making a HydroSpeed and also here for some excellent step-by step instructions. Wear a mask when sanding though!

It takes a weekend or two. I am a pretty clueless craftsman, so it can't be too hard! Spend more time thinking, planning and measuring than you do cutting, and it should end up right. For tools, I found a hacksaw to be ideal, with just the blade with a duct tape handle for long or tricky cuts -- the blade flexes to allow cutting out curves and knee bumps and so on. You cut out the basic outline, and then kneel in position and draw around your legs to get each layer. Pay attention to the trim position as that can be hard to change afterwards. Your centre of gravity is level with the front of the seat (ie directly below your belly button) and not midway between knee and toe as you might expect).

I cut down into my first layer so that the hull was 2 inches thick at the thinnest point. This raises your centre of gravity a bit, but is unavoidable I think. I ended up with an 8" high seat, which is super comfy -- I have NO foot or knee or ankle pain -- woo hoo! This shows the stability of the hull as every inch make a noticeable difference in stability in C1s ...


Spud Spud Spud

It would be possible to make a boat that is 3 foot long, but I think that is going a bit far -- it would be quite a challenge staying upright fore and aft ... However, you should note that I am 6'8" and 240 lbs, so you will probably want to reduce the dimensions somewhat -- you can get lower volume by having it less high -- my superspud is 14" high, you might manage with 11" or 12". I wouldn't go any narrower than 27" as you really really do need the stability that width brings. The key limits are: hull thickness at the knees and feet (1.5" would be the absolute limit I'd say -- this also determines the bow rocker angle), width (27" min) and length (distance from your knee to outstretched toe plus at least 12 inches)

Volume is good! For access to aerial moves and for surfing on micro features, then the more volume the better -- don't be shy of 60 gallons or so ... I have 7 inches of draft (depth below the waterline) but I would recommend going for much less than that -- 4 or even 3 -- this will give excellent stability and surfability. Here is a worked example to get a 4 inch draft for a 150 lbs person: A 4 foot by 28 inch by 4 inch thick slab is about (12.2 decimetres * 7.1 dm * 1.0 dm) = 87 litres. With the corners rounded off this is about 0.9*87 = 78 litres, which is enough to float 78 kg, which minus the weight of boat and gear is about 68 kg or 150 lbs. Add layers for a total boat height of 11 inches and you would be there.

For abrasion resistance and rock protection, I am planning to add a sheet of hypalon (raft fabric) or maybe cordura (rucksack fabric) to the bottom.

The materials cost was not bad when you consider that a new kayak is 700, and this is more fun! I paid 250 / $375 for the Plastazote foam, glue, and hypalon. Ethafoam is cheaper and adequate strength but not as fine-celled and only comes in black.

My 2003 Model

First I drew the 'FlooperSpud'...:

... which I made by chopping down the original SuperSpud:

The FlooperSpud

and it was suddenly possible to do lovely blunt-like manoueveres on flat water. However there was no vertical stability and any kind of bow or stern stall or cartwheel attempt led to instant capsize. And then you roll up straight into a vertical bowstall, which leads to instant capsize ... and so on etc. Double Drat! There's obviously a reason the Wavesport Transformers are easier with extra bits on the end ...

I went one further and chopped off a whole layer to make the SubSpud, which required straps, thinking I could actually loop up instead of rolling up. This did not quite work ... but came close, so maybe cutting even more volume would work? This would be a real pain to keep upright though, looking down at your watch would send you into a bow stall !... ;)

The SubSpud

I now think that the original superspud is an end in itself, a sort of mini-canoe or OC1 (it would meet OC1 rules if you added a tiny airbag somewhere ...). So I will build it back up to it's pram like original bulbous front end.

What I needed next was something a bit longer, a bit thinner, more like a squirt boat, so enter the ...

Squd!

The Squd is a cross between a squirt boat and a spud boat. I had to use a much stiffer foam for this, an expanded polypropylene called PPA30 from the lovely people at Zotefoams, which is 6 times stiffer than LD45, and lighter too. It is a fair bit more brittle and only comes in black and white, but it has done the trick -- email me if you want the equation to work out whether your design will sag in the middle ...

I started with a few drawings (though one of these is the distorted outline of an air45, which I added later when I noticed the similarity. Can you spot which one it is? :)

I went for a very square shape a bit like the top left in the drawing above, figuring I could always carve off more later. I was aiming for just enough to float me, plus 'a bit', so about 120/130 litres. This design also required straps. The first version was way too stable -- I couldn't sink the bow or stern, and broke my paddle on the bottom of the pool whilst failing to roll up ... So radical carving was required ...

The main breakthrough was giving up my initial requirements for symmetry -- while it's true C1ers don't need any footroom in the bow, we do need a bit of width to support us when leaning forward to roll or brace. This version is much better though felt pretty darn hairy at first! Where did all that stability disappear to? After a while got used to it. Yet to be taken on whitewater ...


Living room squirtist: about to execute a perfect offside CarpetWheel ;)

Conclusion

I started out simply wanting to make 'the world's shortest playboat' and see what happened when you take things to extreme. I ended up learning a huge amount about paddling, hydrodynamics, 3D design and styling, and now have a pair of fun craft I will continue to evolve and enjoy. Have a go yourself!

Good luck and have fun!



I>Edwin Datschefski
spud at biothinking dot com August 2002, Updated April 2003

Photo Credit: Many thanks to Joanna Cheski for the living room shots.

Back to Edwin's Paddling Page



Copyright and Intellectual Property Aspects

All designs are copyright Edwin Datschefski 2002, 2003. If you want to make a SuperSpud yourself for your own use, then I permit you to do so on the simple condition that you email me a .jpg of you paddling it.

If you are a kayak manufacturer who wants to take up this idea then do the decent thing and hire me as a consultant for a few days -- I have some other thoughts and ideas that could save you a lot of time and money.












'OK, you can stop taking pictures now ...'