rowerwet

Absolutely, I've gone through the construction process a few times in my head.I would use 1/4" plywood for the bottom to distribute the weight to the roof rack.Probably attach it with U bolts around the bars.The rest could be foam reinforced with nylon straps for better strength. By sculpting the foam the way it is in my sawfish foam kayak, the ends could be very aerodynamic.

I would suggest another layer of foam in the cockpit floor if you don't do the chipboard, I'm not sure canvas alone would be enough

Gorilla glue for foam to foam, Titebond II for fabric to foam

All from the centerline

I've built two teardrops, I like your ingenuity, but most of us don't have all that spare steel lying around. For anyone considering a teardrop or kayak hauling trailer I would recommend finding an old pop-up camper. Both of my teardrops ride on old pop-up camper frames.

It will depend a lot on the type of paint, I can't really give you an answer other than make a sample piece and test it

The foaming kind

you might notice bubbles under the fabric, or end up with sections that come unstuck after being dented. the whole reason I use TBII is because it is able to be reactivated with heat.prick any bubbles with a pin, then lay a cloth over the delaminated area, apply a steaming hot iron to the area and apply heat until any dents in the foam pop out and any unglued areas are restuck.

that is how they pay for this site, besides advertising.you really don't need the whole download to build a boat, the critical dimensions are found on a single page or two. you can write down the station dimensions, or use the screen shot function on any android or windows device, (possibly ios also)

I added a video to the instructions that shows what I'm talking about

Once the fabric is sealed with paint, you can sand it the same way you can sand regular fiberglass smooth.Some people have sanded between each coat of paint to achieve a smooth finish

TBII Doesn't Cure Very Well Between Sheets Of foam.

Update : a recent foam boat builder used polyester resin to coat his XPS foam catamaran. The polyester resin melted the foam, but only slightly, overall the melting was so small that it didn't ruin anything. I would experiment on a sample of foam before trying it on a finished kayak, but you might be able to use polyester resin

Looks great! Hopefully you'll share more pictures.

GS is very soft, and absorbs water, which will cause rot in the plywood. You could do the cut away corners idea with strips of XPS, but be sure to seal the edges of the plywood with epoxy

It will vary depending on how wide, how long, and how tall you make the hull. I would say 400 lbs would be a a safe maximum for a sawfish 12.One builder said he was close to that weight, so he built his 14 feet instead of 12. The kayak is floating just fine with him aboard in the pictures.

Definitely, though it might be easier and more useful to add a socket for a 5 gallon bucket for the live well, and leave the rest of the cargo area for gear, pump, battery, etc.Also don't forget that the water in the well is heavy and will affect your trim and balance. If you look on the kayak DIY project and tutorial page, there are many examples of pet food storage bins with the same screw hatches being converted into live wells

I've mixed materials when I only had eps on hand, it is ok, as long as you keep it sealed

Another builder has added a sail, mostly you will need wood to spread out the loads from the sail attachments

Let us know how that goes, I don't think anyone has tried it yet

I don't see any advantage to adding aluminum strips or angles, getting the aluminum to stick would be hard to do.You also might have corrosion issues. TBII is very base on the acid scale, causing corrosion and rust on metals

I like the parts tray idea. I was not sure about the extra bits of metal around the seat, but it turns out, after a few days of use, they are never an issue.I've never felt them, pinched anything, or even had my pants catch on them. Thanks for your ideas about how to make it better!

if you sheath the whole rack in marine epoxy and layers of fiberglass it will be many times stronger, and still retain the classic looks.study how sailboat fittings are reinforced with fiberglass at every joint and seam, and add multiple layers of epoxy encased fiberglass at the multiple joints in the rack.bore out the bolt holes in the mounting blocks and fill them with marine epoxy, then drill the epoxy to match the bolt diameter.you will end up with a composite rack with classic wood looks, that is stronger than any metal rack ever could be, if done correctly.Gougeon brothers is the company behind the west system epoxy brand, they offer a free manual that will show you what products to use, and procedures to follow, to make these racks not only great looking, but safe.

Are you talking about having a foam box inside, or putting foam or fabric over an aluminum roof

I can, but will be very time consuming. I've recently bought a uncapping roller, a tool from bee keeping. It is much cheaper, and does the same thing

If you are in the US titebond II is easy to buy from Amazon or the home depot website. Outside of the US you have more of a challenge. I posted the link to the manufacturers page so you can get a rough idea of what the glue is chemically. More than one international builder has found a suitable substitute by asking around on local boat building pages, or even carpentry pages dealing with outside projects. The paper coating idea sounds like a lot of work. You might look into the shellac coated paper boat building ideas from around 1900.

If you are on Facebook, there is a mouseboat page, gavin Atkin will give you the link.Otherwise look for his book on amazon or similar, th plans are in the book.

If the kayak is symmetrical bow to stern, the paddlers seat needs to be just behind the center of the hull for balance. If you make the widest point immersed in the water end up further back, you can move the seat back as well. Your center of mass when sitting, is just forward of your belly by an inch or two, because of the weight of your legs

I'll be adding more updates some time this winter, but until then, the revised version is fine. Mostly I plan on making a video tutorial out of each step with links to youtube

Congratulations! A nice looking boat.Soundslike you went for extra strong, on the build. Thank you for the pictures! Enjoy

I don't know if you know about the website duckworksmagazine, but you should send this instructable in as an article. you did an excellent job and the people there would love to publish your build and pictures. just search for duckworksmagazine then look for the submissions tab.

I think the original design would safely carry 300 lbs with no issues. 400 or more in very calm water, the new design will carry more , probably 4-500 lbs with no issues. If you want to carry more weight you can easily make the hull longer, I'm finishing up a 16 foot tandem sawfish kayak right now, the extra length will carry much more weight. For more stability under load make the hull wider. My plan gives you a boat 28" wide minus a little on the water line. Adding a few inches increases the weight capacity and stability, at the cost of a little speed.You can go up to 36" wide before you can't paddle a kayak.The battleyak is 36 inches wide, and Josh Bryie is a big tall guy, he easily stands and casts from it, and he takes his kids with him, along with a battery, trollin...

I think the original design would safely carry 300 lbs with no issues. 400 or more in very calm water, the new design will carry more , probably 4-500 lbs with no issues. If you want to carry more weight you can easily make the hull longer, I'm finishing up a 16 foot tandem sawfish kayak right now, the extra length will carry much more weight. For more stability under load make the hull wider. My plan gives you a boat 28" wide minus a little on the water line. Adding a few inches increases the weight capacity and stability, at the cost of a little speed.You can go up to 36" wide before you can't paddle a kayak.The battleyak is 36 inches wide, and Josh Bryie is a big tall guy, he easily stands and casts from it, and he takes his kids with him, along with a battery, trolling motor, fishing gear, etc. and can still almost paddle as fast as his friend in a plastic fishing kayak.

Glad you made it all work out, hopefully you can enjoy many years of use without any issues. You get hull #24, congratulations!

you can find them on Ebay usually

I like the electric motor much better than the Briggs and Stratton 9 horse that powered mine. https://www.youtube.com/watch?v=2V3gFmnpeYU I was always a little afraid of getting wrapped around the screw myself.

if you search for nor tech screw splitter you can find the video on youtube

TitebondII is very base on the acid scale, if you get any on steel it starts to rust overnight.I use the cheap scissors from harbor freight and change my razor blades often because they are rusted after touching TBII. I don't think you'll have that problem with the expanding foam, people use that for car body repairs often.

Add water, not more than 5-10%, personally I hate the way it acts thinned. It doesn't tack up as quickly, takes longer to dry, and runs easier

Awesome! I always thought it would be easy to make some this way, I just don't need any myself.If you don't mind, i would like to add a page to the instructable showing how you did it.I think outriggers are a great way to have a fast kayak and then also have stand up stability for fishing

You can make any shape out of foam, it may need some wood reinforcement to keep its shape. Im not sure why you'd be afraid your foam Canoe would be light, i prefer my boats to be as light as possible :^) As far as being tippy, that just takes a little adjustment to the design. Heavy materials are best for a hull with a V bottom that settles into the water.Foam barely draws any depth in the water, so a flat bottom with rounded edges will give a stable footing. Just make the bottom as wide as you want the hull, and it will be stable. Sawfish is 28" wide, and I can stand in it easily on the water. The guys who want a design for standing to cast widen that out to 36 inches

24" is a bit narrow, i tried it on one hull and don't recommend it. You would have an easier time by glueing onto the edge of the section you have now.I use a very coarse demolition blade in my skillsaw, they tend to be longer and thicker and resist bending better.

Nice! And don't forget to share pictures!

GS tends to foam up as it cures, and it tends to leave pockets underneath. You may have to repeat the process a few times to get it all solid. On the teardrop site, many builders use the vinyl spackle, it comes in a tub that feels empty compared to regular patching plaster.

Josh added the wood to the battleyak because it has a motor on the back, i don't think any wood is needed for the floor at all.Remember the fabric skin is the real strength of the hull. I stand in my kayak all the time, it doesn't even dent the foam under my feet. I use thick canvas for the cockpit floor and that is all the reinforcement it needs, unless you are wearing spike heels

there really isn't much reason you couldn't use expanding foam. I actually used it as the glue for my foam mouseboat (google "seafoam kayak") I think it might cost you a bit more, and might not be as strong as gorilla glue unless you follow the instructions in the seafoam instructable to fold the foam before gluing with it..i believe there is a guy in the Ukrane building one with expanding foam right now

Another SOF builder mentioned using PLpremium construction adhesive as the waterproofing, i don't know how that works in the long term, as from what I hear, it tends to continue to harden, and eventually becomes brittle

http://forums.wcha.org/showthread.php?9074-Shellac-for-canoe-bottoms this thread gives the best details I've found

Actually I use the Titebond 2 and I really only use it to attach the fabric to the foam. I then fill the fabric with exterior house paint.I did just read on duckworks magazine about a SOF kayak that used titebond II to waterproof the fabric. You might want to look into the wooden canoe forum, and read up on using shellac to waterproof and protect the canvas. That was wat the old maine builders and guides considered the best protection for their canvas skinned boats. They claimed that the canvas just slid off of rocks and showed no damage.

The denser foam will resist dents and dings better, it will be harder to shape with the sureform, so plan on using a hand power plane for that. Laminating foam gives you a stiffer hull anyway, so if you can get thicker foam, do it as it is cheaper. Fabric between the layers will require much more glue.the only place I see an advantage to laminating is to make a SUP.Laminating and skinning foam makes it stronger, im not sure if bending really does much

I have not tested tyvek, the slippery, plasticity feel of the surface lead me to believe it would not stick to the glue very well

So which body of water is that? I'm always interested to see which countries the kayaks are built in.

That looks great! I like the lashing over the compartments also.Definitely looks like it was colder and rougher than my mid winter test launch :)I hope you enjoy your kayak often!

Bought the parts, and never got around to trying it out. I don't have a need to camp in cold weather the way i would have when I first had the idea.I would love to hear how it works out for you.

You might look for 1/8" door skin plywood for the cockpit floor, once glued to the foam, it becomes many times stronger, and the foam is much harder to puncture as well

The biggest problem with EPS (beaded foam) is that the little voids between the beads will suck up and then hold water. The sawfish that was just launched in the Azores is made of EPS, as he had no way to get XPS there. He used a waterseal product to seal the foam, then wrapped it with fabric. I don't know what the long term condition of the boat will be, but if water gets in, it will get heavier and ride lower over time.Obviously this type of foam is usable though, as Snark sailboats as well as many fishing gear floats, and even dock floats are made of it. The trick is getting it well sealed.Your paper mache idea could work if the paper layer is waterproof. I don't know what kinds of paste there are that would remain waterproof, you may know better than I do, or an art supply place or ...

The biggest problem with EPS (beaded foam) is that the little voids between the beads will suck up and then hold water. The sawfish that was just launched in the Azores is made of EPS, as he had no way to get XPS there. He used a waterseal product to seal the foam, then wrapped it with fabric. I don't know what the long term condition of the boat will be, but if water gets in, it will get heavier and ride lower over time.Obviously this type of foam is usable though, as Snark sailboats as well as many fishing gear floats, and even dock floats are made of it. The trick is getting it well sealed.Your paper mache idea could work if the paper layer is waterproof. I don't know what kinds of paste there are that would remain waterproof, you may know better than I do, or an art supply place or artist blog could help.Historically, there was a paper canoe fad back around 1900 or so. it involved paper layers glued into a boat shape with varnish I believe. Polyuerathane might be a more modern material to try. Whatever you try, I would suggest getting a tub or bucket of water that you can let sit for a few days. cut out some foam circles or squares just small enough to fit in the bottom of the container, after being sealed or wrapped with whatever materials you come up with.Once you have your test panel sealed, wrapped and painted, weigh it and record the weight on the panel so you don't forget. Now submerge the test panel in the water, place enough weight on it to make sure it is submerged. After two or three days, get the test panel out, shake off the water and weight it. This should let you know if the seal will work in roughly the same conditions it will when you are paddling your Sawfish Kayak. Unless you plan on an epic paddle with many hours on the water every day (in which case you really should invest in a better boat, IMO) Your test of a few days should be longer than the average paddle, W

a few other people in the comments have run into the same issue, and atleast one has actually launched his boat. (he painted the foam, then sealed it with polyester resin)The only other guy I know who has had a lot of success building with EPS, does a two layer skin of marine epoxy and light fiberglass. But as I said below, this is expensive, costing nearly as much as the rest of the boat.

I really don't think you need the layer of plywood in the hull, as the picture on the first page shows, the hull held me just fine, straddling two sawhorses about 9 feet apart.wood is weight, I use as little as needed. Sawfish has now survived two summers with regular use, and I am hard on my toys.

That will be a new application, most of the people who build these are interested in fishing from them, make sure you share a picture or two of your boat with some game aboard :) !

if you check out my Sawfish kayak instructable, you'll see that I made my kayak out of the same kind of foam, and used no wood for the structure at all.The original Sawfish is now three seasons old, and I keep her strapped to the roof of my car most of the summer, paddling often. Coating the foam with fabric as shown in my poor man's fiberglass instructable keeps the foam from being worn or damaged, and makes it much stronger. I'm still exploring the different ways to build with foam, your catamaran is great!

you mean like this? :) https://www.instructables.com/id/Car-tie-down-ancho...it wasn't original with me either.

Looks great! I'm glad you tried a different way to build the boat.it gives people some options when they don't have the materials I can get. I do think that you will find those extra stabilizer ribs on the bottom will make the boat slower, but that is the beauty of foam, you can change the shape quickly and try new ideas. Congrats on your boat, can't wait to see it in the water!

I started to build this boat years ago, then lost interest. My daughter wanted her own kayak, so I taught her how to build a stitch and glue boat. She did most of the work and got to launch her new kayak this past spring. One change we made was to replace the plywood bulkheads and fecks with foam to save weight. I've gotten to paddle her boat a few times and am very impressed at how fast it is. Now i want to add a rowing rig to it to really get some speed. Glad to see another builder finish one of these.

We stretched the cockpit out further forward as the seating position for a kayak is oposite the rowing one. Sheis actually able to take another kid with her and paddle it tandem.

Awesome!

That is excellent news! I'm glad it worked out and performs as you hoped or better. Little details like the curve at the bow and stern might make the boat a tiny bit slower, or might not, I haven't tried a flat one to compare. Your boat might even be faster. I'll add your boat to the list as soon as I get a chance, Congrats! I hope you enjoy many hours on your new boat!

Fabrics don't like to bend around sharp corners, round them off and they shouldn't fight you. With TBII, it gets tacky and holds quickly. If you are using paint, it takes a while to get to the sticky stage, i use staples to hold the edges down then.

the fabric on the hull adds quite a bit to the strength, dent and puncture resistance, and waterproofness of the seams. you could try the aqua blocker over fabric on a test section of stryofoam, try 1 foot squre, wrap it completly, and coat it with the blocker. when it is dry, weigh the test sample, write the weight on it in marker so you don't forget. then submerge it in water for a full 24 hrs. at the end of that time shake the water off the surface and weigh it again. if there isn't a signifigant weight gain, you shouldn't have much to worry about, as you probably won't be afloat in your kayak for a full 24 hours, more like a few hours, if you are like the average paddler.to see what will happen if you get a hole in the skin. punch a small hole in the fabric on the test sample, and s...

the fabric on the hull adds quite a bit to the strength, dent and puncture resistance, and waterproofness of the seams. you could try the aqua blocker over fabric on a test section of stryofoam, try 1 foot squre, wrap it completly, and coat it with the blocker. when it is dry, weigh the test sample, write the weight on it in marker so you don't forget. then submerge it in water for a full 24 hrs. at the end of that time shake the water off the surface and weigh it again. if there isn't a signifigant weight gain, you shouldn't have much to worry about, as you probably won't be afloat in your kayak for a full 24 hours, more like a few hours, if you are like the average paddler.to see what will happen if you get a hole in the skin. punch a small hole in the fabric on the test sample, and submerge the sample again for 24 hours. at the end weigh it again and see how much water it has taken on.this should answer any worries or point out any problems. Good luck! I am very interested in what you discover!

Small human powered boats come in standard widths, under 36" wide is standard for kayaks, anything wider than that requires a very long paddle. 48" wide is where standard width row boats start. Standard meaning that they don't have out riggers for the oar locks. Unless you are only going to use a motor for propulsion, I believe that you will find it awkward to paddle at 48" wide that is why I recommend stabilizer floats for standing.

And the blue foam is the same stuff, just a different manufacturer.

I would make the boat longer for extra stability and gear holding, rather than wider.My nephews like to sit on the rear decks in their mice, this causes the stern to squat, and the boat to go slower

Not all of the foam teardrop builders use the perforator, many just sand the foam lightly with coarse sand paper. Sanding with coarse paper should be enough, though slower

I can stand up in the original, though I find you must be agile to pull it off as an adult because the boat is so light.Back in July i ran 10 miles on the Saco River in seafoam. At one beach area a group was admiring her, so I spun around to show how easily she can spin in place, which is good on a whitewater river, and then stood up in her as I drifted backwards on the river. They were impressed. I didn't tell them that actually seafoam is not a great boat for whitewater as the center of the v bottom kept grounding out in shallow water that my family in their foam kayaks were skating right through.I found that the trick was to scoot as far into the front of the cockpit as possible, this reduces how deeply the boat sits in the water.

I would recommend the fisherman's mouseboat plan for you, done in foam, I recommend a second layer of foam glued to the cockpit floor for strength. Using canvas over the foam inside the cockpit will make it strong enough to stand on without punctures

Not exactly, I know that the axle is rated at 1,250 lbs, and that the springs are just slightly sprung when loaded. The trailer suspension doesn't really get much motion over bumps when loaded, based on the worn spot on the slipper spring end

After camping in the Adirondacks, where bears are a problem, I think your answer would be an electric fence. The campground had one around each trash dumpster area. They sell portable set ups for camping in bear country, like Alaska.

the 1" is just for the decks, you don't need it unless you want to finish the top of the boat like I did mine.You could just leave the bow and stern open, or use 3/4" for decks. The 2" foam will build a completely functional boat all by itself.Check out the pictures of talon in the comments below to see a deckless boat.

I think you can skin one boat per gallon, possibly more, this isn't a step to try and save on, as the glue bond to the fabric is the real strength of the hull. PLpremium will work for laminating the hull layers, but it is harder to carve away when shaping the hull.Using a power plane would make this much less of an issue. PLp is also harder to get to spread thin, and I don't know how well it will grab into the pores you make with the scoring tool.The bond between the layers is the key to a hull that doesn't flex or sag

As long as it is XPS it will work, the color doesn't matter. I tried some of the Lowe's foam and found it much tougher to shape, requiring me to use the powe plane, which I found I liked better than the sureform anyway. I just can't get 4x8 sheets of XPS at Lowe's locally. Sawfish takes 1.5 sheets of 4x8'2" foam, and 1 4x8' 1", if you follow my Instructable to the letter. Three sheets of 4x8' 2" is enough for two hulls.

Based on the experience my wife had with a boat with just a small skeg in the stern, i recommend a strake that runs most of the length of the bottom. Unless you will be paddling on fast moving water, like shallow rivers, the ability to hold the bow into the wind is a safety issue. The strake doesn't need to be deep, an inch over 10 feet would be plenty. The cutting board strake / skeg is cheaper than anything else I know of.

XPS foam is one solid block or sheet, not a sheet or block made of thousands of tiny beads of foam. Near the water you might look into places that sell foam blocks for floats for docks. The beaded foam, like cheap coolers are made from, are EPS, EPS will soak up water over time, unless coated with a waterproof coating like marine fiberglass and epoxy.The butterfly joint is just a way to clamp the edges together tightly without needing long clamps. As long as the surface isn't smooth the glue should make a strong joint.The joints and layers help the hull resist flexing too much, the fabric skin is really the strength of the boat, you could build it out of cardboard and wrap it the same way with no issues, until the cardboard turned to mush.

Yes, the number of joints won't make a difference in the strength of the hull. The only downside will be extra work, extra cost, and that shaping will be harder as the glue joints are harder to shape without a dip or buldge. Using the power plane to do most of the shaping will keep the seams from causing issues

you still get the record for fastest build, way to go! And great job reeling those fish in! Where would you have been able to order 2" foam from? Just in case more people could use that option also.I'm wondering what dimensions you used on the cockpit, my feet couldn't be over the hatch like that.Is your seat on the cockpit floor, or mounted higher?Congrats on the boat! You are hull #14

No, i don't think it would stick to the fabric as good as the paint does.

TBII will work if you are very patient. It is a water based glue, and that water must evaporate for it to cure. This can take weeks as the foam is waterproof, with wood the water is just absorbed by the wood.Gorilla glue is cured by a process that uses water or water vapor as the catalyst. As long as some water vapor is around, it will cure overnight, even at the 40 degrees F my basement is kept at all winter.TBII might never cure in the basement.

Six days would be a record as far as I know! If i had the time I could build one in three days, but i don't have gime like that.

Styrofoam absorbs water in between the little beads of foam. You can still build a sawfish kayak with it, but will need to seal the foam with a fiberglass skin. This will roughly double the cost, depending on the prices for marine epoxy where you live.For me it would make the cost just a bit over $200 for the complete boat. Do not use polyester resin, it tends to eat foam