Introduction: Sunfish Land Yacht
Sail to the boat ramp!
A great thing about the sunfish rig is that the sail can swivel all the way around. That makes it safer than a landyacht with a stayed mast (held up by guy wires). If one of those landyachts is pointed downwind and gets into a situation where it can't turn, say because of other traffic, there's no way to stop it. The sail gets pinned against the stays. One of those once ran into "THE MAN" at Burning Man and had to be cut apart to get it off. Official Burning Man Vehicle Regulations allow landyachts outside the Black Rock City limits. Windsurfer style landsailers are allowed inside the town as well.
Photos by Kenny
Step 1: Front Fork and Wheel
The front wheel is a cheap pneumatic dolly tire and wheel from harbor freight. I think it was $6 on sale. The fork is from a junked mountain bike. I inserted the fork ends into two pipes. I pried the fork wide open with the two pipes then clenched them again around a big pipe. That made the fork wide enough to straddle the fat tire. I cut the fork short, beat the ends flat, and drilled holes for the axle bolt.
The frame is a sort of cage that surrounds the bow of the boat. It grips the rub rail on the two sides. It doesn't really touch it anywhere else.
It looks pretty complicated, but it's just a bunch of tubes welded together. I first welded up the bracket that grips the rim of the boat. Then I positioned the front wheel where it needed to be. Then I just kept welding more tubes on until the frame was all triangles. Triangles make a strong frame. A rectangle can be squashed by pushing on the corners. But not a triangle. That's why your bike frame gets bent at the front where it's sort of rectangular. The triangular parts of a bike frame hardly ever get bent. Study hard in geometry class to learn why that is. It's useful!
Step 2: Design Paralysis
That's not originally what I thought it would look like.
At first I thought it would look something like this, but that wouldn't give it enough ground clearance.
If only I'd left the fork longer. Oh well.
I had a lot of trouble figuring out how to attach the front wheel to the boat.
I got kind of stalled and couldn't think of an elegant way of doing it.
Step 3: Rear Axle
The rear axle was easy. I had a pair of wheelbarrow wheels and found a pair of big bolts the right size to fit them. I cut some lightweight 2" square steel pipe and welded it into a sort of 'M' shape to match the Vee of the boat's bottom. I drilled holes in the ends for the axle bolts and bolted the wheels on. I put two nuts on the axle bolts and tightened them against each other so they wouldn't come off. I didn't over-tighten the bolts so as to not side-load the bearings too much.
That went great! But how about that front wheel? hmm.
Step 4: Don't Design It, Just Build It
Eventually I remembered that I could build stuff without designing it first.
So I filled my MP3 player with lectures from the London School of Economics, put on my Jackhammer Headphones, and just started welding stuff around the front of the boat.
I had a good collection of junked bikes and broken IKEA chairs to cut metal from.
I used my spoolgun powered by the Solar Golf Cart to do the welding. I ran the spoolgun on 18 volts for the thin stuff and 24 volts for the thick stuff. I used .030" flux core wire. I did the tack welds with the frame on the boat to get the fit right. Then I pulled the frame off to complete the welds so I wouldn't burn the boat.
Step 5: Listen to the Caffeine
I watched my hands cut, fit, weld, and grind pipes into a complicated structure. Meanwhile, on my headphones, I learned about how regression analysis allows statisticians to predict Supreme Court decisions better than actual legal experts do.
And before long, I had a strong lightweight front wheel bracketoganza! And a bit less scrap metal in my way! I tied the axle and the front wheel to the boat, hoisted the sail, and went sailing!
It works great!
Participated in the
Earthjustice United States of Efficiency Contest