J Valve justification

[Ed Palma]

If I recall correctly, one of the justifications for having a J valve (especially for military divers) was to have a low-air indicator during zero visibility dives or dives requiring light discipline. Hard to check an SPG when you can't see it

 

[ronski101]

Great input from all of you. I learned a lot. Thanks.

 

[Thalassamania]

If I recall correctly, one of the justifications for having a J valve (especially for military divers) was to have a low-air indicator during zero visibility dives or dives requiring light discipline. Hard to check an SPG when you can't see it

That's an argument that is still advanced on occasion.

 

[Luis H]

I have two now, and I enjoy playing with them. But, with all due respect, I was diving then and at the time I thought it just another list price selling, "fair traded," ScubaPro/NASDS dodad.

I agree that the depth compensation was always kind of a gimmick, but the adjustable reserve I always thought was very worth wile. IMO going from 300 psi to 600 psi is a worthwhile adjustment.


Now one of the best features about the DCAR valves is that you could take apart and work on the reserve while the tank is full of air. This was particularly useful to me and my buddy when we flew from Puerto Rico to St. Thomas to go diving (back in the 70’s).

We used to drain the tanks to about 100 psi and I used disable the reserve lever so that the attendant at the puddle jumper airline could open the valve and drop the reserve lever and the tank seem empty. When we arrived in St. Thomas I just changed the parts back and at the dive shop they just filled the tanks since they had some air and we went diving. No delays getting VIP, etc.

Yeah…yeah… someone probably thinks this was very dangerous … 100 psi on a 2500 psi tank is meaningless even if the valve was shear off in a crash. The orifice size time the available pressure would have not generated much force at all.

I still think they were great valves.



And as Captain posted...OSHA does require J valves for low visibility dives and I am fairly certain that the Navy does too.