It reminds me of an obsession I had when I was young (maybe 12 or 13) where I kept iterating on a design for a mini-sub I had hoped to build. I must have checked out books on the history of the submarine about that time and became obsessed with the simplicity of the original Turtle submarine — operated with hand screws (propellers).<p>Likely too I saw a homemade sub or scuba tow on the odd Popular Mechanics cover....<p>I had read enough to incorporate a lead ballast that could be released from inside the sub. I imagined props and motors based around those electric trolling motors you can get for a small fishing boat. I therefore incorporated a car battery into the design. Front and rear ballast tanks allowed me to control the pitch trim. I imagined a small electric automotive tire pump would suffice to force the water out of the ballast tanks.<p>I obsessed over a mechanism to allow each trolling motor to be gimbaled from a pair of joysticks in the sub. I built mechanical models with paper drinking straws and toilet paper rolls to test the mechanics.<p>I played with different seating configurations to minimize the size of the sub but keep it "operatable".<p>It was a weird and impossible fantasy that never had a chance of moving beyond the drawing board stage. You know, especially for a kid with a single mother who was a secretary. But perhaps there was some intellectual and creative stimulation that I was feeding off at the time that made the effort worth it.<p>Thinking about it now though, how obsessive I was, it might also have spoke to a boredom, isolation and maybe sadness I felt at the time. The sub might have been an escape for me.<p>To see someone build a sub for real is kind of cool. But it also makes clear how likely my design would have just collapsed right away at about 10 feet depth. I mean, I planned on using plywood for the hull, ha ha.