submarine ballast tank
Would a screen washer pump provide enough pressure to force water in to a sealed pressure tank? Somehow I doubt the theory.
Id try it out in the bath first before putting anywhere near a sub.
This way you wont need to worry about the switch wiring till the ballast system works properly.
You may need to fit a geared pump motor to get over the pressure effect, or it will simply flip the rubber paddles inside the pump element and stop the pump from working once it reaches a certain pressure, same happens if a washer system blocks on a car.
Best wishes.
Gregg
Secretary: Chasewater Model Boat Club.
http:chasewatermbc.blogspot.com/
"The chances of anything coming from Mars are a million to one they say...."