Why? That's a good question...
The whole notion of an amphibious tall couch trike is the beer-induced brain child of a Rat Patrol member, I am simply the conduit between a fantasticly absurd idea which should never have been done, and something that now exists and is actually practicle to use in the real world... But it at all started with beer.
More about the bike at http://www.rat-patrol.org/RPOz/FArt/mitzie.html, beer being essential at every step of the conception, design and building phases...
Step 1: Beer
Fortunately, I had picked up an old bunk bed frame the week before, it seemed to be about the right size and shape...
Step 2: More beer
Also, the couch had to be easy to remove for parties (4 bolts) and the like... good idea! Steer-by-beer was totally going to work!
Now we set about setting the pedal distance before making final decisions about the dimensions of the chassis.
Step 4: Floatation & beer
I figured (hoped) about 300 litres would be fine... I cut the bottom out of the plastic barrels, scuffed the joining surface, then after they had been sitting in hot sun for a while, a few of us smashed them together using epoxy resin and a huge piece of wood... of course, beer played it's part too :)
All of a sudden, the whole structure was totally rigid — wow, it worked really well!! Next we drilled a 10cm dia hole in the side of the barrels, close to the end. So now we had bulkheads, which were filled with expanding polyurethane foam. Bomber.
Next, I used angle iron to make the float base, which had nylon strapping going through lugs to attach the floats. So far so very good.
Step 5: Floatation, beer and propulsion
The floatation frame attaches with only 4 bolts, the floats weigh about 80kg, so it needed to be able to just drop off when required.
So once the drive train was attached and working, we needed an aqua propulsion system — my idea was to use propellers, but that would have become caught in weeds and stuff, quite the hassle when all you want to do is drink a beer.
Fortunately I had outsourced the design, build and installation to some other Rat Patrollians... their idea was to use paddle wheels — it worked (slowly).
Step 6: Testing (with beer)
Funny thing is... IT WORKED PERFECTLY THE FIRST TIME!!!!!!!!! Didn't expect that. Mmmmm, beer, the sweet taste of success :)
Step 7: Living the dream
Off we go the the Rat Patrol Oz 2007 FLOATilla
That's 7 pretty easy steps on how to make a tall amphibious couchbike, right?
So, what's the next project...? Sleep :)