Hi Fred, the switch is a magnetic latching switch, you move the magnet over it left to right to switch on / latch power to Rx.
Then right to left to unlatch and switch power to Rx off
I knew nothing about model subs.till a friend asked if I could get his sub working for him.
I now know they have a magnetic switch to power up the Rx, levellers that should work with dive vanes
Tank cylinder piston gearboxes piston control units, rudder servos,vane servos, limit switches,fuses
Twin ESCs and a Messed up Tx.
I am glad to say I did the repairs and alterations needed to get the boat working as it should again after a lot of wire
Tracing and continuity testing. Never again.
John