The original sled was built from ethafoam in 1980 and was my first squirt design- named the “Slake”. I used it to do the first eddyline mystery move at Lost Paddle rapid on the Upper Gauley of Sept. of 1981. I called it an “Under” because I was actually going for an ender but bit off more than I could chew- over and over again. It’s the lower green boat- compared to the Hunch made in 2014. The Slake seemed small at the time.
A “sled” is a small genre of make it yourself sit on top craft which is used for mystery moves (intentional submersion) in safe arenas. Please don’t do anything scary in them. I’ve created this blog to show the steps I took in creating my latest. This one took 21 hrs. and about US$400 in materials to make. I used abandoned (contributed/re-purposed) styrofoam and epoxy.
The steps are pretty simple. Think of it as similar to building a surfboard- a foam core- then surrounded by glass layers. The beauty of it is that you can evolve the design if you please as you go along – with no real detriiment. Keep in mind to build it strong. I give standard recommendations as I go along.
So.. you start with a design. I like to start by carving foam- but you can also design on the computer or a sketch . But- ultimately- you need a full size paper copy of the side view and top view profiles of the sled.
For the top view- I like ellipses- but anything goes. I’ve found 20” wide and about 8’ long is a good starting point. But this is a good format for trying new designs- so follow your instinct and imagination.
For the side view- you need to cue in on certain crux dimensions- like the thickness at the feet, knees, hips, and just behind the seat. You can guess, or take measurements from a squirt boat- or another sled. But think of it as 7” is usually plenty for the knees- often less. Behind the seat should be less than 4”- don’t worry too much about it- everything can be adjusted as you go. Hips- maybe 6” and toes- 4”.
So- for the side view profile- buy a 4X8’ sheet of ¼” luan paneling- or if you can’t find that- try some strong paneling. Use it as a table and put a long sheet of paper on it to make your pattern out of. Then draw a long line and set up the arc of the hull in relation to that line by using a curved stick to set the curve. This is the ‘rocker’ of the hull- except in my case this boat has negative rocker- or what I call a ‘drop bow’.
OK~ that step is over and you can set it aside. You’ve made one ‘stringer’ that will remain in the sled and two side templates which will help with the shaping later on. Now you need to source foam- 2 lb. Styrofoam is a good choice. Try to get as big of pieces as possible because glue lines will give you trouble later on. If you can find someone who has boat docks- they have to replace their dock flotation sometimes and may have scrap pieces laying around that they would be glad to re-purpose. My friend Peggy Pings was my ‘angel investor’ on this project.
So… now.. you are ready to start assembling the sled. You need to bond it together with epoxy. I like WEST system with the fast hardener and I make a slurry of it with micro spheres and glass strands. So- this sled is to be 20” wide and I want the plug to be oversized to start with so I’ll make a 21” wide plug. That means I need two 11” wide halves assembled to each side of the central stringer. First I prepare the foam for bonding by cutting the foam into 11” wide by 8” thick foam blocks- added up to make the 8’ length.
So- now- set up a jig across both ends to help position the side templates.
OK- the side view profile is established quite accurately now. It’s time to put on the paper top view profile template and cut the shape out with a hack saw blade or handsaw- be gentle- it’s fragile now.
I don’t want to go into a long spiel about layups- you can do your own. But suffice it to say I’m not a big fan of Kevlar- I prefer polyester fabric- available from Sweet Composites. A good lay up- in order of assemblage- is: polyester, 4 layers of 10 oz. glass, polyester and finally a couple ‘scratch’ layers of 10 oz. glass. Later- you can paint it with white epoxy to make it smooth.
So- basically- that’s how you get to a testable sled. If it isn’t perfect- go after it with a grinder, putty, more glass, wood- whatever. Jungle rules apply- do whatever works. Once the shape is established- I add dynel bumpers (about 15 layers) around the last 15” of the tips to take rock hits better. Then grind them smooth. Once all the shape is fine and dandy- you can paint it over- hull first and deck later- with epoxy mixed with white pigment. Email me if you have any questions or suggestions. firstname.lastname@example.org
Keep the knowledge going- free fun for everyone!