Progress so Far: Here's where she stands so far. Chasis is almost complete. The screw is finished, sealed and painted but not yet mounted beneath the boat (see screww sitting off to right side). All gears and sprockets are mounted and working. Click photo for larger version.
Gears and Transmission: Finally got it all welded together and running! All that's left is to mount the screw and steering mechanism. Here are a few photos of the transmission (5 speed) system which powers the flywheel and screw. It shifts using a standard bike shifter mounted to the steering rod (not installed).
Notice the RPM gauge. I kept this from the original excercise bike because it's useful to monitor revolutions per minute. This is important information to know. There will probably be a point where additional pedal revolutions do not add to overall craft speed due to screw cavitation, thus finding the sweet spot and staying there will keep me from wasting energy spinning the screw faster than it needs to go.
Also, there is a brake on the back of the flywheel to stop the thing from spinning as the drive pedal is ratcheted and cannot stop the flywheel or screw from turning by simply not pedaling. Braking the flywheel in turn brakes the screw. I can spin the flywheel (in air) about 60 mph and it is not easy to stop and has a dangerous amount of momentum, thus I needed the standard caliper brake from a ten speed to slow it down. The amount of resistance in water will of course be greater, thus less speed and momentum, but I still felt the brake was needed just in case.
This week: Completing the chasis and mounting the screw beneath the frame.