Introduction: Catamaran Stand Up Paddle Board (SUP)

Picture of Catamaran Stand Up Paddle Board (SUP)

This is a fiber glass catamaran stand up paddle board or simply SUP. SUP boards are more related to a boat like construction rather than a surfboard. The sport of stand up paddle boarding came about in the era of surfing. It is a much larger board used along with a paddle in a standing fashion, to explore, race or surf. The shape and weight will be more determining of what the board is suitable for. This particular model I designed for a fast, long distance, touring style. My board is 12'6" long by 28" wide and weighs around 30-32lbs. The catamaran shape is great for a more stable board. I have not surfed with it as of yet and it is not suitable for a race that has many turns due to the lack of surface area in the rear (the method used to turn a sup is shifting the weight to the rear, raising the nose). Hope you enjoy! Btw:  Eventually I would like to create these completely hollow. If you like what you see, I would appreciate any help. Below is a link on how you can help. Thank You!!!

Step 1: Foam

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Buy Blue insulation foam. Panels are 4x8 feet and about $14. You will need 3-4.

Step 2: Cut Foam

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Once you have traced a design you like, sketch it on the foam. Measure twice cut once!!

Step 3: Place Pieces Together

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Before any glue is used, place the pieces together to make sure they fit correctly.

Step 4: Glue

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I used water resistant glue since it will be glassed later anyway.

Step 5: Cut Upper and Bottom Parts

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Once the basic shape is glued and pieced together you will need to make the top and bottom of the pontoons.

Step 6: Glue

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Once it is fitted and glued. Begin shaping. I used 150 grit sand paper.

Step 7: Second Pontoon

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Repeat the steps for the second pontoon.

Step 8: Middle Piece

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Join the two pontoons.

Step 9: Deck

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Add a deck to stand on.

Step 10: Shape

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Shape using sandpaper. Take your time.

Step 11: Get Rid of 90 Deg Corners

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I added a rounded edge underneath to ease with glassing.

Step 12: Glassing

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Add fiber glass. Use two part epoxy.

Step 13: Add Fin Boxes

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After adding 2-3 layers of fiber glass prepare fin boxes. Research angles for the size you are building. Also add any leash holds or net holds at this time.

Step 14: Paint

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Design a color scheme and begin painting base color first.

Step 15: Design

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Continue with your design scheme. I chose a post apocalyptic look.

Step 16: Glass/epoxy

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You can finalize with a thin 4oz fiber glass to seal the images or glass with epoxy alone. Add the epoxy with a brush and add 3 layers total. Let the epoxy sit for 3 hours exactly before its cured to add the next layer.

Step 17: Help Support Us!!

ATTENTION EVERYONE!! I have launched a small campaign to fund my company PH822 Composites & Design. Please checkout the link below for a chance to purchase a high quality T-shirt with my logos on the front and back. I have 21 days to meet my goal of 282 shirts (but I can go above)!!!!! Please share at the very least!!!


vakrepulo (author)2017-02-23


I have a few questions:

What kind of fiber glass did you use? (I mean: How much the weight of it?)

How many layers of fiber glass did you use?

thanks, vakrep

JefferyC9 (author)2016-07-14

So did you vent it? Seems like it might explode being hollow like this. Did you ever get a solid weight range figured out on this. Surely with the volume dimensions and lack of weight it would hold in the 200lb range.

The only question I really have is what did you use for glue and how many tubes did it take? I've heard gorilla glue works well for this application and comes in tubes. Is glue expansion not a problem with the flexibility of the foam?

mayala6 (author)2016-03-17

Thank you LeslieP7

mayala6 (author)2016-03-17

Foam 1" thick

LarryD16 (author)2015-11-02

What thickness of foam board did you use?

LeslieP7 (author)2015-09-22

Now this is pretty cool. This is the first I ever ever seen designed like this. If this works, I'm sure it will be the next "big thing" on the water.

I just purchased a SUP from They may be contact for you if this Catamaran SUP works.

Good Luck!

LeslieP7 (author)2015-09-22

mayala6 (author)2014-10-17

.... Ummm I'm sorry I don't speak Russian

mayala6 (author)2014-10-17

Was about 30lbs

paracorded_inspirations (author)2014-03-13

How heavy is it once completed

C_B (author)2013-05-18

пенопласт от эпоксидной смолы плавится, как решили эту проблему?

pintoc2 (author)C_B2013-09-28

эпоксидной смолы не плавится накладки из пеноматериала

pintoc2 (author)pintoc22013-09-28

Убедитесь, что вы используете морской эпоксидной она лучше всего работает с набивкой из пеноматериала

mayala6 (author)2013-07-11

Haha. Well Thankfully when I was younger my parents were ok with house projects. I've been playing with composites since the age of 20 so about 12 years now. My apartment is a little small for housing projects but I do what I can. I currently have a launched T shirt campaign for my company to get a little head start and will be launching a kickstarter campaign soon. If your interested in helping our company grow please visit and at the very least please share!! :)

PaulLee97 (author)2013-07-11

This is is great! Wish my parents would let me make something like this! And great paint job. Love it!

mayala6 (author)2013-07-09

Ps use a new razor

mayala6 (author)2013-07-09

The dimensions are 12.5 feet in length by 28" wide. Each hull is 8" wide and the space left between will be 10". The thickness at the nose begins with 7.5-8" and tapers down to 5.5" at the center, down to 4" at the tail end. The cutting was done by marking both sides of the foam equally and then cutting half way in from both sides. This way you have a straight line on both sides. The final shaping was done by hand and a keen eye ;) lol. Hope that helps. Please share our site. We are starting a composites company and we have t shirts available and a goal of 282 sales by the end of 2 weeks and 1 day now. Thank you.

nate_hartzfeld (author)2013-07-08

love this indestructible! Any way you could post details of how you cut the foam and the dimensions?

mayala6 (author)2013-07-03

Shirts for sale and to help support PH822 Composites. I added two pictures at the end of this instructable. FYI you will not be charged until I meet my goal of 282 shirts at the end of 21 days. So please share and help support us.

mayala6 (author)2013-05-25

I don't know haha. It's not really made to be motorized....

swmprat0u812 (author)2013-05-25

This is really AWESOME! How controllable would it be with a converted weedeater to trolling motor? My 12" john boat really moves and it weights over 100 lbs.-

mayala6 (author)2013-05-24

Hello. No rudders used in this design. The 10" fin boxes are fixed for best straight performance. It's a smooth glide. :) typically At 12'6" no need for a rudder... But you may be able to turn better if you added the rudder due to the lack of surface standing area. I can only walk so far back to raise the nose and turn.

bvisser (author)2013-05-23

I can do this, and I like the catamaran design; more stable for us older, tall guys! I was surprised at the use of rudders; do you think they're beneficial with this design? I would almost think the cat style would keep it straight, but I do like to paddle in a straight line, so are they worth the extra effort, in your opinion?

mayala6 (author)2013-05-20

As far as this shape, I liked the different look. Not only that, but because you stand on two pontoons (is that correct spelling?) it is much more stable even at 28" wide. Due to the learning process, I used excess fiberglass; however, it's still at a manageable 30-32 lbs. it's shape allows for a straighter and faster stride. I wouldn't consider it a race board, but it is a smoother faster touring board. There are some drawbacks; due to the lack of surface, one can only step back 2 feet to raise the nose for a turn. This is the reason why it is not a good surfing/racing board because it does take more time to turn around.

DEA1286 (author)2013-05-20

Awesome instructable! Such a unique and original design! Can't wait to see what you come out with next!

flyingpuppy (author)2013-05-20

How does it handle compared to a regular paddle board? Why did you choose this shape? Excellent instructable, btw.

mayala6 (author)2013-05-20

Mean time I'm starting a small composites company. Very small now but years of history and thought process. This is a video I put together, hope you guys like it.
Check out this video on YouTube:

mayala6 (author)2013-05-20

Not sure about a kayak. Although I can install pvc reinforced holes that would allow for a chair like structure and maybe that would help to lean and rest to paddle in a kayak method.

mayala6 (author)2013-05-20

Weight capacity so far I've tested up to 160-170. But working on a new paddle and fin design an will test with my 225lb brother in law haha. Thank you all. It's my first paddle board and I made many mistakes doing it. I know now better methods and learning proper vacuum infusion for a stronger and lighter version.

muzzdafuzz (author)2013-05-20

look great..what is weight capacity

mdlmusic (author)2013-05-19

Wonder how that method would work for a sit-on-top kayak?

bsg68 (author)2013-05-19

That's pretty cool

bethmwl (author)2013-05-19

Very nice. You have a great deal of patience. I can see me starting such a project and not completing. I would like to construct a similar 'boat' and wonder if I can pull it off. I think you did an excellent job.

mayala6 (author)2013-05-18

Guess we can't type polish haha.

mayala6 (author)2013-05-18

Przepraszam ale nie mówię po rosyjsku. Czy pan mówi po polsku?

mayala6 (author)2013-05-18

Glue? The foam was glued with a water resistant glue but only to hold shape. Once it's glassed with a two part epoxy and fiberglass, it is fully water resistant. I did install two nylon screws on each hull top that can be utilized as a pressure release valve.

kerenel (author)2013-05-18

What glue did you use?

mayala6 (author)2013-05-17

Thank you. A sail? I don't know... I've thought about a rudder though. Maybe the next one I make. I'm working on another soon :)

lscott13 (author)2013-05-17

I love the amount of pictures you used. Very amazing and helpful. Awesome instructable.

basementhacker (author)2013-05-17

Do you think that you could add a sail and rudder? Make it a boat?

mayala6 (author)2013-04-16

I have not tried it in waves. It does move faster than any surf sups but i have not raced it against a much lighter racing sup. It is slow to turn around though because it does not have space on the back to stand on and raise the nose a little. I would consider it a fast recreational cruiser.

gathem (author)2013-04-16

Very cool!
++ for unique hull design
++ for the unique artwork

I just shaped a 12 ft SUP from a solid block of foam, and glassed it... It was no small task. Mine doesn't look as good as yours. Very nice job

gathem (author)gathem2013-04-16

You mentioned testing it. What is your primary use for it? Surf/race/flat water cruiser?
I am curious how this would handle in waves with the unique shape. I am guessing this is better for cruising or racing if it keeps you high enough out of the water than only the two pontoons are in the water. I just cant imagine it working well in waves, because normally a wave comes up behind you, and there would be less to ride on the wave. I would think it would be good if your goal was to smoothly go over the waves, but not so much if you wanted to ride it. I am just guessing, I really don't know.

mayala6 (author)2013-04-16

Thank you. I have tested it. I know it can carry me, but I'm only 5'7" 150lbs. I've been trying to get my brother on it to test (5'9" 170), if that works I may try my father at 5'8" 190.

Gregbot (author)2013-04-16


l8nite (author)2013-04-15

very nice design, any idea what kind of weight it can carry ? (displacement)

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