CG43
Contributor
The great advantage of the doubelhose is that they provide warmer air because the inner and outer ribbed hoses act like heat exchangers. As soon as the water is no longer warm, I dive only with double hose reg. . The airflow is more even and the air is not shot through the mouthpiece at high speed. Together with position-dependent breathing, it is somewhat similar to a rebreather.
The disadvantages of the double hose were pointed out here.
For practical use, one can make modifications that reduce some disadvantages.
For example, one can separate the first and second stage to attach the second stage directly to the backplate or BCD, which Cousteau/Gagnan already did with the CG43.
Then the membrane sits close to the shoulder blades even with different tank sizes.
You can't buy something like this ready-made at the moment, but you can easily build such a regulator from the modern Aqualung doubelhose or other single hose regs.
For examble , here's my CG43 version made from Dräger firefighter components.
The backplate accommodates tanks from 4 L to AL 80.
The hoses can be unscrewed for simple flushing.
The valve-less mouthpiece (like CG43) can be closed with a plug.
The second stage can be opened without tools in 20 seconds and closed in 30 seconds .
I used a littel lathe and mill to build thie CG43 clone , but 3D should work too .
