Scuba tanks and compressor
We use carbon scuba tanks which have a volume of 6.8 litre. Very light and small. They are good for 300 bar (4500 psi), while normal tanks are usually for 200 bar (3000 psi). 300 bar x 6.8 = 2000 litre. That is the same amount of air as in a 10 litre tank at 200 bar.
We have a Nardi compressor, which can fill at 300bar/100 litres per minute. It runs on 230 volt. I installed a soft start to reduce the peak load for the generator. The reason I went for the Nardi is that it comes standard with auto drain and auto stop. I installed it aft of the starboard engine. I transferred the start/stop button to the cockpit and made a quick connection, so that I just have to plug in a short filling hose which is connected to the tank. I can keep the engine room lid closed at all times, so the compressor runs very quiet. I modified the air intake such that it takes air from outside. Just behind the plancha, under the overhang.
Where to keep the scuba tanks?
I installed two tanks on port side, two on starboard side near the steps to the deck. Not too much work. The white brackets are Bainbridge part A096wt. I use 4 per tank. There are 10 in a package. The straps are from Plastimo item 42667. Four in a bag. They are long enough to make two sets from one, but you will need to stitch them together. Or just order more and throw away the excess length.