Pat - I KNOW it sounds strange, or like I have heard from polluted sources or not understood, but I was standing in the pump room touching the #2 compressor as the guy who rebuilt it explained everything. The sump seems an odd place, but it saved space. Sure, a pain to get to for repair, but not all that bad and they hoped repair wouldn't be nec in the field. The oil made an excellent temp transfer, increasing efficiency.
All the "strange" things this guy has encountered on fleetboats have proven to be well-reasoned to his astonishment.
I honestly don't know about il/water filtration, I'm assuming there was some, I only mentioned the cooling because it related and would certainly help.
There were 5 Fleetboat air systems:
1 - 3000lb main (not directly tied to anything)
2 - 600lb Ballast blow and torpedo firing (comes from 3000 reduced)
3 - 225lb service air (run tools at 100psi, blow various small tanks) (comes from 3000 reduced)
4 - 10lb (finish blowing ballast) (independent compressor)
5 - salvage air (salvage teams could tie in and blow water from a sunken boat or flooded compartments)
That's all I know!
Maciek - The Gato inclined flasks I have seen too, they seem to be inclined ONLY to conform to the hull casing (the "V" of the bow) - and were used for firing torps.