Brand new to Double Hose diving

[simonbeans]

I totally appreciate your interest in "learn(ing) a bit about it". Most of what you are asking has been discussed for many years, and for some of us, explaining again is a bit tiresome. (Sorry). Especially when VDH has a very active forum and a great search engine. I am of the "old school": "Give a man a fish and you feed him for a day. Teach a man to fish and you feed him for a lifetime", which in this case is for you to do some research on the double hose regulator and in specific the items that you seem to be interested, i.e., DBE, HPR, Phoenix 1st stage, silicone diaphragms, etc. You might look in the download section of the VDH website (tab at top of home page) and read about the development of the Royal Aqua-Master.
I don't want to sound like (as Nemrod says) a "grouchy old coot", but for your first regulator, it is best to have a professional technician like Bryan refit your reg. That way you will have a great baseline of how a well tuned double hose should perform. (A long time ago there was a guy here in NY that was trying to set up his own USD AM. He said he couldn't get it to breathe well at all. Somewhere along the line he never learned that the tabs on the main diaphragm need to ride on the demand levers of the second stage).
I wish you well in your new adventure. There are great divers of double hose regulators available to help, just try to educate yourself with the information that has been learned through research and experience.

 

[ffdiver]

I think I'll just be sending the reg over to Bryan.

I had this romantic vision of me tinkering away on a vintage reg making it divable and being all proud of it. But in all reality, I'll break something out of frustration and my wife wont feel comfortable with me diving a reg I worked on myself.

Thank you all for the information.

 

[John C. Ratliff]

I totally appreciate your interest in "learn(ing) a bit about it". Most of what you are asking has been discussed for many years, and for some of us, explaining again is a bit tiresome. (Sorry). Especially when VDH has a very active forum and a great search engine. I am of the "old school": "Give a man a fish and you feed him for a day. Teach a man to fish and you feed him for a lifetime", which in this case is for you to do some research on the double hose regulator and in specific the items that you seem to be interested, i.e., DBE, HPR, Phoenix 1st stage, silicone diaphragms, etc. You might look in the download section of the VDH website (tab at top of home page) and read about the development of the Royal Aqua-Master.
I don't want to sound like (as Nemrod says) a "grouchy old coot", but for your first regulator, it is best to have a professional technician like Bryan refit your reg. That way you will have a great baseline of how a well tuned double hose should perform. (A long time ago there was a guy here in NY that was trying to set up his own USD AM. He said he couldn't get it to breathe well at all. Somewhere along the line he never learned that the tabs on the main diaphragm need to ride on the demand levers of the second stage).
I wish you well in your new adventure. There are great divers of double hose regulators available to help, just try to educate yourself with the information that has been learned through research and experience.

SimonBeans, that is hilarious!

ffdiver,

Once you get the regulator, get in a pool and try it out. The Nike addage, "...Just Do It!" applies here, as these regulators are not at all difficult to use, just slightly different. Instead of a purge button, you simply need to take the mouthpiece out of your mouth and hold it higher than the regulator and it will free flow. Or, take the mouthpiece out of our mouth, and instead of looking up, turn your head to the right (left side down) and blow and it is clear. If the exhalation hose is flooded, simply exhale as your are rolling to your right (left side down) and the water will be removed from the hose--easy and fun.

Enjoy,

SeaRat

 

[ffdiver]

I ended up buying another reg that was already upgraded and converted to a phoenix! So, now I have 2. You guys were right these things multiply. I should be able to get the PRAM into the pool tomorrow. Any last minute advice before I do?

Things to try out and mess with aside from clearing the reg?

 

[Ed Palma]

Man, this thread got me remembering my first time! Just get used to the over-all feel of the reg. I'm sure you've heard by now that positioning is crucial to get optimal reg performance. Lucky you, you're starting out with a PRAM Here's my first time with a DA Aquamaster from some time back.

[video=youtube;4K_xtYwKvx4]https://www.youtube.com/watch?v=4K_xtYwKvx4[/video]

 

[herman]

Doc you are talking about DH diving aren't you?

Besides reg placement you may need to change the way you breath. Some people tend to breath a bit faster and shallower with a single hose reg, DHs work best if you take longer, deeper, slower breaths. Many divers don't like DHs at first until they get use to using this slightly different breathing pattern.
Another thing to know/remember is since the diaphragm is on your back if you are at the surface and lean back or allow the cans to get below the mouthpiece under water, THE REG WILL FREEFLOW, that is normal. Depending on how it is set up ,it may go into a strong freeflow, the venturi can be quite effective, esp if it has a HPR installed. To stop it, either put the mouthpiece underwater at a depth below the cans or just plug the mouthpiece with your hand. I am going to be at the surface a lot of the time, I will use a mouthpiece plug to prevent the free flow and to free up my hands.

I would also suggest you practice clearing the hoses. Water will get in from time to time and you need to get it out. Remember the exhaust hose is on your left. There are a number of ways to do is but this is how I clear a hose with a fair amount of water in it.
I roll with my left side down and hold that position for a breath or 2, that gives the water time to run to the cans and that will get most of the water out after a breath or 2. For a lot of water or if I want to do a better job, after a couple of breaths I take a deep breath and as I do a long slow exhale, I complete the roll - left side and hold, then roll all the way over to face down, exhaling all the time.

 

[Ed Palma]

Doc you are talking about DH diving aren't you?

Let's see... I got wet, didn't go too deep, wasn't too sure of what I was doing, did some hose-clearing, and when it was done, I wanted to go again. Yep, talking about DH diving there

 

[JohnN]

I am of the "old school": "Give a man a fish and you feed him for a day. Teach a man to fish and you feed him for a lifetime",

I always thought it was

Give a man a fish, and you feed him for a day. Teach a man to fish, and he'll sit in a boat and drink beer all day

 

[Nemrod]

The reason you should not pant (shallow quick breathing) with a double hose (though still not correct with a single hose) and instead take long deep breaths (and exhalations) is because much of the work of breathing with a double hose regulator is overcoming the pressure differential between your lungs and the regulator (above your back generally at a shallower depth and lesser ambient pressure) to initiate flow. Once flow is established the Venturi effect assists pulling the diaphragm inward maintaining sufficient demand flow and reducing inhalation effort. Shallow breathing does not take advantage of this characteristic.

Yes, single hose regulators have a Venturi design as well but it is not as critical nor nearly as powerful as that of a double hose regulator. A well tuned double hose, once flow is initiated, you can back off and just sip the air for a long inhalation. Obviously, if you think about it, this reduces the WOB vs taking five short and quick shallow breaths in the same interval of time. And no, we are not skip breathing, we are using controlled breathing.

The new Argonaut has a well designed case that promotes a strong Venturi effect, better than the DA/RAM though they are no weaklings by any stretch.

N

 

[John C. Ratliff]

Nemrod above has some good points. Some of the positioning he mentions can be largely overcome by lowering the regulator on the back. I wear my double hose regulator lower than most, even vintage, divers. I use longer hoses or super flex hoses to allow this to occur. Well-designed double hose regulators, as Nemrod states, have a very good venturi that once flow is initiated doesn't stop until the diver starts an exhale cycle. Saying that, I don't use different breathing style with a double hose regulator than with a single hose regulator. I use a deeper inhalation than most. In order to understand this, you need to understand the physiology of breathing.

As I sit here typing, I am using only my "tidal volume" (see the graph below from the current U.S. Navy Diving Manual). This is rather shallow breathing, and what most people use when doing light activities. New divers also breathe only with their tidal volume. But in doing so, a low volume of air is exchanged, and the percentage of the dead air space in the diver's respiratory system (trachea, bronchioles, mouth, etc.) that is rebreathed is higher. This results in a greater percentage of your own CO2 being rebreathed, and can give rise to a condition called "hypercapnia" even in open circuit diving. We still have our "Expiratory reserve volume" and our "Inspiratory reserve volume" that can be used for respiration. When I dive, I use this entire "Vital capacity" for my respiration. In insures that I exhale the majority of my CO2, and that I get the required amount of oxygen into my tissues. But this must be learned, and most divers who have dived for any time do use a large proportion of their Vital capacity. This also helps in maintaining control over buoyancy while diving.

I would urge all divers to re-read this section of the U.S. Navy Dive Manual, Version 6, Volume 1, Chapter 3, about the physiology of breathing. It is a good review, if nothing else. Here is what it has to say about "Dead Air Space."

Respiratory Dead Space. Respiratory dead space refers to the part of the respira-tory system that has no alveoli, and in which little or no exchange of gas betweenair and blood takes place. It normally amounts to less than 0.2 liter. Air occupyingthe dead space at the end of expiration is rebreathed in the following inspiration.Parts of a diver’s breathing apparatus can add to the volume of the dead space andthus reduce the proportion of the tidal volume that serves the purpose of respiration. To compensate, the diver must increase his tidal volume. The problem canbest be visualized by using a breathing tube as an example. If the tube containsone liter of air, a normal exhalation of about one liter will leave the tube filled withused air from the lungs. At inhalation, the used air will be drawn right back intothe lungs. The tidal volume must be increased by more than a liter to draw in theneeded fresh supply, because any fresh air is diluted by the air in the dead space.Thus, the air that is taken into the lungs (inspired air) is a mixture of fresh and deadspace gases.

SeaRat