Long hose & dh and other potential traps of faulty thinking

[luis]

You could figure out a way to use a double hose with a long hose...but why? Why point does it serve? If you are in some crazy cave, then a doublehose isn't the best choice.

Why not?

I agree that for my alternate regulator or decompression gas / stage cylinder regulators, a single hose is by far the better choice. But my regulator of choice as my primary regulator for any extended range or overhead environment (AKA technical diving) is a double hose regulator.

I used a DH regulator as my primary regulator for my technical diving classes.

For any extended decompression diving I also used a Phoenix RAM as my primary and a Conshelf (1st stage)/ Scubapro 109 (2nd) combination for decompression gases including O2 stage. The same thing for ice diving and wreck diving.


The only time I can see a Dh being somewhat inconvenient is if I am traveling and I need to borrow or rent a set of modern doubles with outlets on the on the side. But, I have already been thinking of ways to use my DH in that situation. IIRC, the Cousteau team used triples with the regulator to the side when they did the Britannic.

I am not a cave diver and have no interest on doing any Florida caves, but if (or when) I do some Cenotes in Mexico it will probably be with an Argonaut HPR double hose regulator.

[Ron]

"Why not?"

Simple, and it has to do with design engineering. A double hose doesn't breath as well as a single hose when head down. Most cave diving is done with the body at primarily a horizontal body position. If I were selecting gear on practicality, and not just on nostalgia or "just because", then I would pick a single hose for caves and caverns. It's engineering, as you already know, is such that it breathes best when you are facing downward with respect to the horizontal axis. Equipment wise, it's the best choice for a cave.

I don't dive caves, so I dive a doublehose whenever I want to do so. I'm just examining the practice as a point to how I plan missions. I didn't tote a Garand rifle in Iraq. It's not that it isn't a great rifle, it was just designed with a different set of criteria in mind.

Having said that, do what you want. I'm all for people doing what they want. For me, the doublehose is part of the kit that goes with vintage styled, free spirited, ocean diving. I love wearing a DH, a cotton harness, some shorts, some full foot fins, a fish bowl mask, and that's it. No computers, no danglies, etc. If I have to haul around trimix or something, then it isn't vintage (for me) anyway. Still, do what you like. I'm just telling you what I do. I'm not the SCUBA police, that's someone else on here LOL.

[luis]

Well, of course I am going to do what I like… but thank you for approving it (twice).

If you haven’t notice, I don’t dive a double hose because it is vintage. When I started diving the double hose was not vintage and most of the DH that I dive now-a-days are not vintage either. They are vintage style and do have the advantage of a long history and technical experience behind them, but the Phoenix HPR, the Pegasus, the Unicorn, and now the newest regulator, the Argonaut… are all vintage style, but they are not vintage.

I don’t agree with your assessment of a double hose performance. One of the primary reason I dive a double hose is because I like their performance… in every position. The way I tune my regulators and how I wear them (touching my back), I like their performance as much or better as anything I have tried… in 40+ years I have tried a few different regulators and other breathing devices.

Over the years, I have designed several modifications that have improved regulator performance. One of the most significant was the new back plate. That did not apply to my double tanks since I don’t use any back-plate with them. My technical rig uses a harness and a horseshoe wing attached directly to my doubles.


You should have noticed that nostalgia is not what drives most of my decisions. As an engineer function comes first.

I do need to point out that you are confusing the engineering with basic physics. Some may consider it a technicality, but there is a big difference between the two. Design engineering is what I do… physics is what I have to work with. It is what nature give us to work with… in this case, for example the pressure differential in the water column.

I don’t think that I need to expand about breathing performance and the water column… but there is a lot more than just that fact of physics when it comes to choosing an underwater breathing system.

When I was at the Navy Experimental Diving Unit and the Navy dive Depot, I had an interesting discussion with a couple of the engineers/ researchers about “work of breathing” and “perceived work of breathing” … someday when we get together, I will expand on the subject. But, let me just say, that what you perceive (as work of breathing, or anything else) is extremely important. That is part of “human systems engineering”… a subject that I am having to expand (my limited) knowledge as fast as I can.


Remember, what you consider vintage… to me is actually just diving gear… I was around when it was new.
And when it comes to DH... it is now new again...