HI well I don't know if anybody eles has had one of these revel blue devil destroyer model kits but In that it had a idea of the ship goin to a set course by a plastic disk that is turns slowly by the motor gearbox an the disk could be changed with others of a different shape to move the rudders on the ship eg. one disk for a complete circle another to do a figure of eight an another for just straight running if I rember rightly there was about 5 different disks
chris
The results of the Blue Devil self steering in real life were always subject to the accuracy of the build and weather on the day. Anybody who remembers non radio sailing will be familiar with the concept that a free running boat, if it doesn't actually go straight, will do a spiral course. Or a semi circle hitting the launch bank a bit further along.
This 4 by 2 tank, are we talking feet, yards, metres? What size of boat?
A slot system needs a deep enough slot or a guide system to cater for lumpy water.
The best idea so far is the clear plastic sheet with a heavy steel wire describing the course and a magnet to keep the boat over the wire. Maybe a magnet each end, maybe a front magnet on a swivelling arm linked to the steering. Thinking back a long way, there was a trolley bus system that derived its steering from its overhead pick-up. It handled curves and corners great, but having finished with a corner, was incapable of going straight. To make the constant steering corrections look reasonable, the trick was to park other vehicles strategically for it to "steer round". Eheim strikes a chord.