Did you ever wonder how the Scubapro first stages got that low pressure (LP) line out of the end of the first stage? Well, that happened because the Navy Experimental Diving Unit (NEDU) in 1970 evaluated the Scubapro Mark I against the Mark V, and found that the Mark I out-performed the Mark V. Why? Because the Mark I had only one LP port, and was less expensive, but that port was out of the top of the first stage. Because of that, there was no 90 degree turn in the air flow going into the LP hose. If you have a modern Scubapro regulator, and want the maximum performance out of a LP port, use the top port. Here is the NEDU report that triggered this change.
The interesting finding by the NEDU was that when the adjusting knob of the second stage was closed, the regulator did not pass the NEDU criterion for acceptance. The Scubapro Mark I and Mark V were therefore not recommended for U.S. Navy use.
This document is 26 pages long, with several charts of the regulators' performance. There are also diagrams of the test site and information on the test procedures.
SeaRat
The interesting finding by the NEDU was that when the adjusting knob of the second stage was closed, the regulator did not pass the NEDU criterion for acceptance. The Scubapro Mark I and Mark V were therefore not recommended for U.S. Navy use.
Cave divers wanted this adjustment to de-tune the regulator in high currents so as to not free flow because of the current (at least, that is what I have heard).
This document is 26 pages long, with several charts of the regulators' performance. There are also diagrams of the test site and information on the test procedures.
SeaRat
