Pesky,
The Snark III works pretty well with either of these hose systems. It is the equivalent of the USD two hose systems with my internal modification and either the USD hoses or the Hope-Page mouthpiece. The Snark III has such a large exhaust valve in the case (mushroom valve) that it will "leak" air because of the pressure differential between the outer edge of the mushroom valve and the center of the lever point for the diaphram. But it does not leak air due to the venturi effect (I have two others that do a bit, the Trieste II and the Sportsways Hydro-Twin, both of which are equipped with LP and HP outlets).
By the way, I saw on Discovery Channel that the US Navy is now using Snark III regulators exclusively for their initial SEAL training, as there are now no other double hose regulators on the market. They don't use SPG's either in the initial training, at least.
The nice thing about the Hope-Page is that it can be used with currently available Self-Contained Breathing Apparatus (SCBA, not SCUBA) used by fire departments and many, many other organizations when entering a space with an IDLH atmosphere (Immediately Dangerous to Life and Health).
I have an original Aqualung DX regulator that I've rebuilt, with the venturi hose within the right hose and a metal mouthpiece that directs venturi air down the diver's throat (like today's single-hose regs). It was the one of the best breathing two-hose regulators made, but the original hoses were too short, and some said the "tasted bad" too. I've equipped this regulator with the SCBA hoses from a safety supply house. With 6 moving parts, which never need replacement, and an old-style flutter exhalation valve, it will be going for many more years.
Getting back to the "J" valve discussion, my twin 42's are set up with a twin "J" manifold (reversed, as mentioned above). This unit has the Sherwood SVB 4000 JD with Reserve duel outlet manifold, with two separate regulator mountings. Because I've reversed the valve configuration, I can wear a double hose regulator and a single hose regulator. In this way, I can still use the older double hose regulators and have a complete octopus, LP hose for my BC, etc.
The reason that these tanks had a pull rod was the positioning of the scuba in the harness system. To use a double hose regulator effectively, the regulator should be between the shoulder blades. Wearing it higher increases the breathing resistence by raising the regulator higher in the water column in relation to the center of the diver's lungs. All my harnesses are set up this way, whether or not I'm using a double hose regulator, for one other reason--it's much easier to swim on the surface with the tank low on the diver's back. The higher the tank, the more it will push the diver down when on the surface.
I mention this because, in one of the posts above, I heard that divers are now being taught to wear their rigs high enough to reach over your shoulder to be able to access both the regulator and the tank valve. That post said that this is the reason pull rods are no longer being used.
I take exception to this position. The tank's harness should be worn, in my opinion, with enough strap length to allow a diver to comfortably snorkel in a near-horizontal position (say 30 degrees from horizontal) on the surface. I've heard that there have been diving fatalities on the surface from divers who cannot snorkel in a chop and swim to shore a few hundred yards. With today's snorkels, that situation can only happen when the become exhausted from surface swimming. Wearing the tanks too high will contribute mightily to that situation. If the valve is between the shoulder blades, the tank will be low enough on the diver's back so as to allow good surface (snorkeling) position while in scuba. Try it in a pool, if you are not convinced. Also, at the end of the dive, many aluminum tanks are actually a bit bouyant empty. Worn lower, the buoyant bottom end will help the diver attain that near-horizontal position so desirable for surface swimming.
SeaRat
The Snark III works pretty well with either of these hose systems. It is the equivalent of the USD two hose systems with my internal modification and either the USD hoses or the Hope-Page mouthpiece. The Snark III has such a large exhaust valve in the case (mushroom valve) that it will "leak" air because of the pressure differential between the outer edge of the mushroom valve and the center of the lever point for the diaphram. But it does not leak air due to the venturi effect (I have two others that do a bit, the Trieste II and the Sportsways Hydro-Twin, both of which are equipped with LP and HP outlets).
By the way, I saw on Discovery Channel that the US Navy is now using Snark III regulators exclusively for their initial SEAL training, as there are now no other double hose regulators on the market. They don't use SPG's either in the initial training, at least.
The nice thing about the Hope-Page is that it can be used with currently available Self-Contained Breathing Apparatus (SCBA, not SCUBA) used by fire departments and many, many other organizations when entering a space with an IDLH atmosphere (Immediately Dangerous to Life and Health).
I have an original Aqualung DX regulator that I've rebuilt, with the venturi hose within the right hose and a metal mouthpiece that directs venturi air down the diver's throat (like today's single-hose regs). It was the one of the best breathing two-hose regulators made, but the original hoses were too short, and some said the "tasted bad" too. I've equipped this regulator with the SCBA hoses from a safety supply house. With 6 moving parts, which never need replacement, and an old-style flutter exhalation valve, it will be going for many more years.
Getting back to the "J" valve discussion, my twin 42's are set up with a twin "J" manifold (reversed, as mentioned above). This unit has the Sherwood SVB 4000 JD with Reserve duel outlet manifold, with two separate regulator mountings. Because I've reversed the valve configuration, I can wear a double hose regulator and a single hose regulator. In this way, I can still use the older double hose regulators and have a complete octopus, LP hose for my BC, etc.
The reason that these tanks had a pull rod was the positioning of the scuba in the harness system. To use a double hose regulator effectively, the regulator should be between the shoulder blades. Wearing it higher increases the breathing resistence by raising the regulator higher in the water column in relation to the center of the diver's lungs. All my harnesses are set up this way, whether or not I'm using a double hose regulator, for one other reason--it's much easier to swim on the surface with the tank low on the diver's back. The higher the tank, the more it will push the diver down when on the surface.
I mention this because, in one of the posts above, I heard that divers are now being taught to wear their rigs high enough to reach over your shoulder to be able to access both the regulator and the tank valve. That post said that this is the reason pull rods are no longer being used.
I take exception to this position. The tank's harness should be worn, in my opinion, with enough strap length to allow a diver to comfortably snorkel in a near-horizontal position (say 30 degrees from horizontal) on the surface. I've heard that there have been diving fatalities on the surface from divers who cannot snorkel in a chop and swim to shore a few hundred yards. With today's snorkels, that situation can only happen when the become exhausted from surface swimming. Wearing the tanks too high will contribute mightily to that situation. If the valve is between the shoulder blades, the tank will be low enough on the diver's back so as to allow good surface (snorkeling) position while in scuba. Try it in a pool, if you are not convinced. Also, at the end of the dive, many aluminum tanks are actually a bit bouyant empty. Worn lower, the buoyant bottom end will help the diver attain that near-horizontal position so desirable for surface swimming.
SeaRat
