I went to a dive shop and told them that I wanted two things:
A fifty foot hose that would attach to my dive tank regulator and a an air-jet nozzle that I could attach to the other end of the hose. I told them I also wanted to be able to attach my octopus to the end of the hose for a quick dive on the propeller, etc.
They sold me what I needed with quick-disconnects to use the new 50 foot hose as an extension so that I could dive without kitting up, leaving the tank on deck...AND...I can attach an air-jet nozzle to that same line for general compressed-air projects on the boat. Of course, a strong jet of air is needed nowadays to clean the reconstituted corn that is left in the outboard engine carburetor by ethanol which is added gasoline. grrrr.