Double hose manufacturers
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sealark
Contributor
Thanks for the site, just looked at it great improvements I'm sure it took a lot of work and time. If I was younger than 73 I would get one just to see the differences. Not a bad price either.
I'm newish to diving and really know nothing about DH setups. But, I have read this whole thread. Now I'm curious and have questions.
How does the WOB bench test relate to the real world inhalation effort when the diver is in a position where the mouthpiece is 1 foot (or however far it would be) below the 1st/2nd stage of an AK?
I think one of the comments I read - or maybe it was in info on the DSV on the VDH site - said that the AK will freeflow on the surface. If there is an orientation that will cause it to freeflow, then doesn't that also imply there is an opposite orientation that will make it hard to draw a breath?
Does the DH setup create any noticeable pull if you try to turn your head all the way to either side?
Do the big fat hoses on either side of your head interfere with peripheral vision in any head position?
I gather that, if you are satisfied with the ease of breathing from a normal, modern SH reg setup, then the benefits to the AK are that it dumps the exhaust bubbles behind you, so it's quieter and the bubbles don't interfere with your vision. Other than nostalgia or looks, is there any other tangible benefit to the AK over a good SH setup?
How does the quietness and reduced bubbles of the AK compare to using a side dump reg like a Poseidon?
I did a demo dive on a DR O2ptima CCR and I didn't really like the feeling of having all that "stuff" on either side of my head. Glimpses of it in my peripheral vision seemed like it made me feel just a little claustrophobic. Looking at pics of people with a DH setup make me wonder if a DH wouldn't make me feel in a similar way to when I tried the CCR.
How does the WOB bench test relate to the real world inhalation effort when the diver is in a position where the mouthpiece is 1 foot (or however far it would be) below the 1st/2nd stage of an AK?
I think one of the comments I read - or maybe it was in info on the DSV on the VDH site - said that the AK will freeflow on the surface. If there is an orientation that will cause it to freeflow, then doesn't that also imply there is an opposite orientation that will make it hard to draw a breath?
Does the DH setup create any noticeable pull if you try to turn your head all the way to either side?
Do the big fat hoses on either side of your head interfere with peripheral vision in any head position?
I gather that, if you are satisfied with the ease of breathing from a normal, modern SH reg setup, then the benefits to the AK are that it dumps the exhaust bubbles behind you, so it's quieter and the bubbles don't interfere with your vision. Other than nostalgia or looks, is there any other tangible benefit to the AK over a good SH setup?
How does the quietness and reduced bubbles of the AK compare to using a side dump reg like a Poseidon?
I did a demo dive on a DR O2ptima CCR and I didn't really like the feeling of having all that "stuff" on either side of my head. Glimpses of it in my peripheral vision seemed like it made me feel just a little claustrophobic. Looking at pics of people with a DH setup make me wonder if a DH wouldn't make me feel in a similar way to when I tried the CCR.
captain
Contributor
Regulator positioning. If the regulator is bumping you in the back of the head when in a horizontal position it is too high. It should remain directly between the shoulder blades. A crotch strap helps in keeping it position.
Vintage Double Hose • View topic - Double Hose Regulator Position CRUCIAL!!
Vintage Double Hose • View topic - Double Hose Regulator Position CRUCIAL!!
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All of that doesn't really say what happens if you do it wrong. Other than the one sentence that implies that it makes it harder to breathe.
This seems to add up to saying that if the reg is shallower than the mouthpiece, it makes it harder to breathe. And that even the difference between being a little higher on the diver's back combined with being on a single tank on a "conventional" (bent plate) back plate makes a noticeable difference. Enough difference that some people would notice and call it "harder to breathe".
Is that it?
Again I ask, how does an AK compare for quietness and bubbles in your vision to a side dump reg like a Poseidon? The most annoying thing to me about my conventional regs is how loud they are. Especially if I'm wearing a hood and the bubbles sound like they're beating on drums held up to my ears.
This seems to add up to saying that if the reg is shallower than the mouthpiece, it makes it harder to breathe. And that even the difference between being a little higher on the diver's back combined with being on a single tank on a "conventional" (bent plate) back plate makes a noticeable difference. Enough difference that some people would notice and call it "harder to breathe".
Is that it?
Again I ask, how does an AK compare for quietness and bubbles in your vision to a side dump reg like a Poseidon? The most annoying thing to me about my conventional regs is how loud they are. Especially if I'm wearing a hood and the bubbles sound like they're beating on drums held up to my ears.
(expand the above to see my answers to each question )
DH regs feel different and it's hard to explain the difference, you have to feel it for yourself. Some prefer them and others don't. I have a number of regs, single hose and double hose, modern and vintage. My go to reg of choice is a modern DH reg, esp if I have a camera in my hand.
Thanks, Herman!
IWC? In Water Cracking Pressure? So, from your response, I deduce that having the mouthpiece 1 inch below the main diaphragm makes it twice as hard to inhale. Is that really what you meant? You said the baseline is 1 IWC (presumably, when mouthpiece and diaphragm are at exactly the same depth/ambient pressure, as in a test machine), and with the mouthpiece 1" lower, the inhalation effort would be 2 IWC (i.e. double the effort).
And if you go totally head down (e.g. you're looking under a reef ledge that is just barely above the bottom and you are trying to take a picture of something under there)? Inhalation effort gets noticeably more difficult?
IWC? In Water Cracking Pressure? So, from your response, I deduce that having the mouthpiece 1 inch below the main diaphragm makes it twice as hard to inhale. Is that really what you meant? You said the baseline is 1 IWC (presumably, when mouthpiece and diaphragm are at exactly the same depth/ambient pressure, as in a test machine), and with the mouthpiece 1" lower, the inhalation effort would be 2 IWC (i.e. double the effort).
And if you go totally head down (e.g. you're looking under a reef ledge that is just barely above the bottom and you are trying to take a picture of something under there)? Inhalation effort gets noticeably more difficult?
I'm outta here.... Good luck guys
Yea, it does change but its not as pronounced as you might imagine. IWC = inches water column
My best advise if you want to try one is to find someone who dives them regularly and knows how to dive a DH and get them to take you on a dive. I come up to Lake Rawlings ( I know it's changed names) a time or two each summer, be happy to bring a few along for you to try.
Yea me too Bryan, see you soon.
My best advise if you want to try one is to find someone who dives them regularly and knows how to dive a DH and get them to take you on a dive. I come up to Lake Rawlings ( I know it's changed names) a time or two each summer, be happy to bring a few along for you to try.
Yea me too Bryan, see you soon.
Right behind you and Herman, the Double Hose Caribbean Resort Divers Club. But I will try one more time ----
How can a dh regulator breath equal to a sh regulator?
1. Mechanical advantage - you might notice that dh reg has a much larger main diaphragm than a sh reg. This increases the mechanical force available over a single hose for a given pressure drop. Where does the pressure drop come from, your demand when you begin to inhale. The area of the diaphragm is a force multiplier. Pressure Delta X Area = Force
2. Much stronger Venturi - The Kraken has a much stronger (and adjustable) Venturi than previous dh designs and much stronger than a sh reg (they do not need it so much). High volume flow is sustained with little effort required.
3. Lower cracking effort and improved stability - the Kraken can be set as low as .3 inches and is quite happy around .5 inches whereas the typical sh hose reg is set around .9 to 1.2 inches. The HPR second stage design offers improved stability and allows an IP as high as 150 psi though most run around 135 psi.
4. DSV- in previous dh designs if the Venturi was set as strong as the Kraken then flow would bypass the mouthpiece and continue out the exhaust, flow in excess of demand. The DSV has a vane which redirects the air flow and helps to eliminate bypassing. The secondary benefit is the DSV allows is the ability to shut the airflow off for surface operations.
Low cracking effort reduces the effort needed to initiate air flow, the powerful Venturi amplifies and sustains the demanded flow, the DSV eliminates bypassing of the air mass flow. The HPR second stage allows stable high IP and low cracking adjustments that would otherwise cause free flow and the DSV allows shutting the air circuit off while on the surface.
Realizing most people do not have the flow gauges, Magnahelics and other tools to measure and adjust and critically analyze SCUBA regulator performance, but some of us do. Most folks just go buy something and use it and if it does not act right drop it to the LDS (and cross their fingers and pray). They have no idea of how the things work or how to adjust them. This explains why the above four points have already been explained in this thread more than once and yet the same questions are asked over and over as if the posts are not actually being read, either they are not being read or the concepts are foreign?
Positional sensitivity, all regulators, sh or dh have positional sensitivity and the following chart is exactly correct in it's presentation:
This:
Is not this:
Additional improvements over old dh regs back in the olden times:
1. Thin, light, super flexible silicone main diaphragm
2. Flexible light weight hoses
3. Large silicone exhaust valve instead of a duck bill valve
4. Mouthpiece cage vales with improved design and silicone valves
5. HPR second stage
6. Integrated LP and HP ports
7. DSV
Other characteristics:
1. Quiet, smooth, no bubbles exploding by your ears and yes it is quieter than a side exhaust
2. For photographers there is no scary bubble face to frighten animals allowing closer approach and no bubbles interfering with your photo composition.
3. The mouthpiece has no weight so it does not pry down on the jaw or require biting force to retain
4. Anti-ice formation design for cold water
5. Streamlined
If one is not willing to learn a new normal then best stay with your poodle jackets and gurly mahn single hose regs.
Nine out of ten sharks interviewed for this story prefer to eat single hose SCUBA divers:
And by the way, the first stage is the same as a Conshelf, Titan, Legend and the second stage is a downstream design not unlike that in a Conshelf or any of dozens of single hose regulators. Exiting stage left.
N
How can a dh regulator breath equal to a sh regulator?
1. Mechanical advantage - you might notice that dh reg has a much larger main diaphragm than a sh reg. This increases the mechanical force available over a single hose for a given pressure drop. Where does the pressure drop come from, your demand when you begin to inhale. The area of the diaphragm is a force multiplier. Pressure Delta X Area = Force
2. Much stronger Venturi - The Kraken has a much stronger (and adjustable) Venturi than previous dh designs and much stronger than a sh reg (they do not need it so much). High volume flow is sustained with little effort required.
3. Lower cracking effort and improved stability - the Kraken can be set as low as .3 inches and is quite happy around .5 inches whereas the typical sh hose reg is set around .9 to 1.2 inches. The HPR second stage design offers improved stability and allows an IP as high as 150 psi though most run around 135 psi.
4. DSV- in previous dh designs if the Venturi was set as strong as the Kraken then flow would bypass the mouthpiece and continue out the exhaust, flow in excess of demand. The DSV has a vane which redirects the air flow and helps to eliminate bypassing. The secondary benefit is the DSV allows is the ability to shut the airflow off for surface operations.
Low cracking effort reduces the effort needed to initiate air flow, the powerful Venturi amplifies and sustains the demanded flow, the DSV eliminates bypassing of the air mass flow. The HPR second stage allows stable high IP and low cracking adjustments that would otherwise cause free flow and the DSV allows shutting the air circuit off while on the surface.
Realizing most people do not have the flow gauges, Magnahelics and other tools to measure and adjust and critically analyze SCUBA regulator performance, but some of us do. Most folks just go buy something and use it and if it does not act right drop it to the LDS (and cross their fingers and pray). They have no idea of how the things work or how to adjust them. This explains why the above four points have already been explained in this thread more than once and yet the same questions are asked over and over as if the posts are not actually being read, either they are not being read or the concepts are foreign?
Positional sensitivity, all regulators, sh or dh have positional sensitivity and the following chart is exactly correct in it's presentation:
This:
Is not this:
Additional improvements over old dh regs back in the olden times:
1. Thin, light, super flexible silicone main diaphragm
2. Flexible light weight hoses
3. Large silicone exhaust valve instead of a duck bill valve
4. Mouthpiece cage vales with improved design and silicone valves
5. HPR second stage
6. Integrated LP and HP ports
7. DSV
Other characteristics:
1. Quiet, smooth, no bubbles exploding by your ears and yes it is quieter than a side exhaust
2. For photographers there is no scary bubble face to frighten animals allowing closer approach and no bubbles interfering with your photo composition.
3. The mouthpiece has no weight so it does not pry down on the jaw or require biting force to retain
4. Anti-ice formation design for cold water
5. Streamlined
If one is not willing to learn a new normal then best stay with your poodle jackets and gurly mahn single hose regs.
Nine out of ten sharks interviewed for this story prefer to eat single hose SCUBA divers:
And by the way, the first stage is the same as a Conshelf, Titan, Legend and the second stage is a downstream design not unlike that in a Conshelf or any of dozens of single hose regulators. Exiting stage left.
N
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