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
17 Comments
11 years ago on Introduction
This is amazing! i would like to see a video, if at all possible.
13 years ago on Step 5
you are awesome......
14 years ago on Step 4
I disagree i alway design and think throu my projects
Reply 14 years ago on Introduction
Well hello mister fancy pants.
14 years ago on Introduction
small flaw... I have sailed sunfish before, I have even won a race in one of those little fun craft. But one thing I noticed before I became comfortable with these is... they capsize, alot. And tell me if I'm wrong but wind still equals capsize even with three people on board I have capsized. Do you have ballast, maybe sandbags.
14 years ago on Introduction
Amphibious FTW! :)
14 years ago on Introduction
Hey Tim I love the mounting scheme and the reuse of the bicycle frames! Why'd you go with a tricycle plan? I thought about trying this with an old Sunfish hull but I'd always planned on making it a tail-dragger, with the main wheels mounted on either side of the daggerboard slot and the steering gear mounted just like the rudder, with a steering arm. That way it would steer more like a sailboat. Your design is probably more tip-resistant in high winds, but where's the fun in that?
Reply 14 years ago on Introduction
At first I thought I'd make a bracket that could mount at either end, and try front and rear wheel steering. Then I was going to do the next one as a tail-dragger and compare them. The front wheel steering lets you put more weight back on the big axle. The front wheel is lightly loaded, but turning throws the needed weight on it. Iceboats switched to front wheel steering to avoid spinouts when the rear steering blade lifts. When you shift your weight back there to hold it down, it makes the boat tippy by unweighting the wide front.
Reply 14 years ago on Introduction
OK yeah, I can picture that. Even if you put the main gear all the way forward, you're still fighting the wind to keep the steering gear on the ground. On the water you can hike out to keep the rudder in the water but I wouldn't want to do that in a parking lot!
14 years ago on Introduction
I think a reverse trike set-up with tiller steering would work great. You could use the daggerboard slot as the mounting point of a two wheeled cradle, then mount your steering wheel at the stern, possibly using some of the original rudder parts. You could pick up some speed by taking the bend out of the upper mast might be able to flip it) and adding a vang to pull down on the gooseneck. Brakes? Looks like fun!
14 years ago on Introduction
Is the boat just wedged into the front wheel assy? I can't see what's holding it in place. If it were to pop off while you were sailing, you would grind away the bow on the concrete.
Reply 14 years ago on Introduction
There's a rope bridle going from the rear axle to the stern of the boat.
There's another rope bridle going from the front assembly to the rear axle.
That one is cinched tight with a trucker's hitch.
14 years ago on Introduction
Back in '73 I built a Manta from plans by Popular Science. It worked great! This is so reminiscent it is almost freaky. The Manta had a steering wheel that really simplified things. I could have one hand on the wheel and the other controlling the sheet. Heeling was easy to control as the lift drops off when the yacht tips. I used it a couple times and then the local shopping center started opening on Sundays. But what a hoot that was.
14 years ago on Introduction
I see the front fork is controlled by ropes and the ever-present inner tubes- have you considered hitching the control ropes to the tiller so you can steer just like regular sailing?
14 years ago on Introduction
That's pretty sweet, can it float when it goes through water?
Reply 14 years ago on Introduction
Absolutely!
Reply 14 years ago on Introduction
Nice!!