If anyone is interested I have made a homemade torpedo and designed the electronics to provide the timing and speed of the motor.
The design is based of the Mercury Thrust electric prop.
The unit has 2x 7 segment display to display time and motor speed settings.
Has terminals that caters for any switch setup whether normal switch or reid.
Timing is based on 5 - 40 minutes and increments of 5 minutes.
A very clever unit and price is cheaper that most timing units available plus designed for this purpose alone.
Relays will be required to drive the higher current outputs for the 3 speed options.