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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 ...see more »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? :) http://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.
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...see more »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
Is that better than the little cap that comes on the bottles? I'll have to try this
I find synthetic fabric doesn't stick as well with the TBII, it may require a different glue.An interesting approach to try some time
You're welcome, I love hearing about.I believe you are the builder of the fifteenth sawfish! If you have any pictures or a name for your boat, we would all like to see them
I've looked into just about every type of boat building, I like the skin on frame idea, except for the possibility of getting hole and possibly sinking. Is fuselage frame like, skin on frame? I ended up with foam as it is unsinkable, is very light, and won't rot, rust or corrode
You can also locate where you want stuff, then make a larger hole in the foam than the screws, and pack the hole with PLpremium, insert the screws and hold them in place until the glue cures. Heat a screwdriver with a lighter or torch and hold it in the head of the screw until it softens the glue enough to thread out.Of course wood gives you an easier way to mount and move them. I hope you share some pictures of your boat
I estimate that the foam in the hull should displace over 300 lbs, with gear and other stuff you both were probably pushing 300 lbs.Splicing in a foot or two in the middle of the hull will increase the useful load of the boat
The only thing I can think of is trying commercial foam insulation installers, or Craigslist. I amon the east coast and have not seen any good answers to the CA problem
Great stuff is hard to foam into a solid shape, it tends to leave voids and be weak.It also soaks up water like a sponge. If you got any holes in the fabric skin it would suck up water and get heavy.The xps is the structure of the boat, spray foam is not stiff enough
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