Group: Past Members
We have a portable Brownies Hookah system: http://www.browniesthirdlunginfo.com/vs-hand-carry-portable-brownies-electric-recreational.shtml
It has been great for doing work on the props (adjusting the pitch on our variable pitch props as I tuned them) and cleaning the bottom of the boat. The couple of times we have hooked lobster pots or floating lines, I have not bothered to get it out, but it would certainly have worked fine if I hadn 't been able to clear the lines quickly with a snorkel. Running on 12 volts, you can 't go very deep with it, but for maintenance projects that is not needed.
As posted before, you should get some training for any compressed air system. Brownies does offer an online course as part of the purchase cost.