[PSUBS-MAILIST] Hard Trim Tank Questions

[djackson99@aol.com]

So, now that I am plumbing my soft trim tanks I'm thinking about hard trim tanks should the soft approach not work out. 

The tanks would only need to be a couple of cubic feet each, fore and aft and I was thinking about 3 solenoid valves per tank for vent air, blow air and flood.  The flood valve would be a 1/2" direct acting valve, and the other two much smaller gas valves.

So what has been done for controlling hard trim tanks?   

And how do you know the current state of the tank?  In other words, is anything done so that you know the water level in the tank so you know your reserve.  I'm wondering if a magnet on a float on the side of an aluminum or PVC tank with reed switches on the outside of the tank would be worth the effort?

Thanks
Doug J
www.SubmarineBoat.com