[PSUBS-MAILIST] over pressure valve

[hank pronk via Personal_Submersibles]

Personally I think an onboard compressor is a much safer option than an over pressure valve.  There are multiple safety benefits to an onboard compressor, over pressure being the biggy.  With a compressor you can get rid of the pressure without surfacing and trying to control a perfect ascent.  With the OPV you have to surface a bit and let air out and wait then surface more and wait and so on. You can't just surface and hope the valve keeps up with the demand. This is more important for subs with large domes.
The next benefit to a compressor is, if you lost all your air, you surface by dropping your weight.  In my case the weight is small and I would also drop the thruster and tail assembly.  Still, not much sub out of the water.  With the compressor, I can open my vent valve in the hatch and use the compressor to fill the ballast tanks.
Hank