As I mentioned a couple of posts ago , we were trying to decide which type of marine life we were going to try and imitate for the next sub race.
A few of the creatures that we were considering are:
Seahorse – I can see a really cool sub, single operator, about 8-9 feet tall with twin flapping fins on the back. The operator would be sitting upright on a conventional type bicycle arrangement. Stability would be pretty easy to maintain, due to the height of the sub. The tail could easily be used for steering. Entry would be thru a side hatch. For a propeller type drive I would use about a three foot diameter low rpm prop. The subs height would easily counteract the large props torque.
Squid – This could also be a great looking sub. I would probably cast the whole hull out of urethane or silicone with some free trailing tentacles for effect. The drive could either be a water jet operated by a squatting motion or a bicycle type drive powering a peristaltic pump for the jet bursts. This would be a straight thru water flow with intake thru the nose and exhaust thru the stern. The trick would be to be able to vary the jet orifice during the exhaust cycle for optimal vortex formation. Steering and dive/climp could be accomplished by warping the hull in the apprpriate direction, remember that it would be cast out of a flexible material.
Sea Snake – Now this one would be a challenge, remember we are trying to mimic the creatures motion using human power. At this time I don’t think that this is a viable choice. There are a number of robotic snakes in existence, but they are all controlled with computers and many servo motors. The efficiency of a human powered drive for such a creature would be so low that it would be hard for one person to get it to move.
Turtle – This would provide a nice large hull for the operator/s. The general motion of the fins would be up and down with a reversing pitch of the fin to match the direction of movement. The fins on each side could be operated independently in order to steer the craft. Overall, a relatively simple craft although efficiency would be fairly low. Operator drive motion could either be linear motion or a typical bicycle type drive.
Jellyfish – Now this is my personal favorite. It probably would be as inefficient as a sea snake, but imagine, a ten foot diameter silicone bell with simulated bioluminescence. How cool would that be? OK there are a few minor details to work out, steering, dive and climb, and of course, how do you contract the bell material to prevent flaps in the material like in a closed umbrella? Also, the opening of the bell must be controlled to create a nozzle shape while it is closing. How hard can that be for a human-powered vehicle? The operator could open and close the bell via a 1:1 squatting drive or a variable ratio pedal drive, either linear or circular.
A decision will be made by this weekend. Stay tuned.
By the way, The garage shop is clean and ready to go, Alibre is loaded, so all that’s needed is to choose a direction and start moving in it.