Underwater nail gun - GIF

[carl blum]

Hi Gang:
So roughly each foot of depth reduces available air pressure by 0.5 PSI, So if you were running the gun at 100 PSI at 40 foot you would only effectively have 80 PSI available. But if you were exhausting into a rigid hose to the surface you would still have 100 PSI and it would help if the exhaust hose was larger than supply. Plus the big advantage of not stirring up dirt in the water.
On factory air cylinders we would route all the exhaust air back to a common muffler.
Carl.