kotori

Onboard compressors are what we used to use before CO2 became widely available. Open the case of a 12v bicycle (or automobile) air compressor, and you can remove the guts of the system. This makes for a much more compact air source that is only limited by your batteries. You still need to build a electric pressure cutoff switch, and figure out some way to protect the system against water, and prevent electrical noise from a high-current, cheap chinese motor from interfering with your electronics. They are also only half the size of a 20-oz CO2 bottle (not counting the battery), so the space and weight savings is questionable. I tried one, but was not impressed with the result. Electrical noise from startup disabled both my ship and a nearby teammate's ship. I drifted across the pond, while my teammate got swarmed and sunk just outside the Axis harbor. After that, I switched back to CO2.

External compressors are a different story, however. They're basically the same thing, except not removed from their factory-designed case and not installed in a ship. We use them to charge up the single-shot "torpedo" cannons on destroyers and cruisers. In this role they work very well, since you can power it from a car battery instead of your ship's onboard batteries. Also, something about leaving a compressor in its factory-designed case helps reduce noise both electrical and audible, preventing issues like what happened to my test onboard compressor ship.