The usual answer is that when a panicked OOA diver tears your primary out of your mouth, you won't be doing much giving nor have much of an opinion or choice.
Upgrade to a longer primary hose
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The usual answer is that when a panicked OOA diver tears your primary out of your mouth, you won't be doing much giving nor have much of an opinion or choice.
OldNSalty
Contributor
This should not be scary, you were taught regulator recovery so you have been at depth with no second in your mouth. As long as your octo/safe second is in a predictable and secure location (thus the idea behind Air2 and bungied octo) then switching to it at depth is a non issue imo.
I use a 40" (or maybe it's 44") hose with a 70 degree elbow for my primary regulator. I have done so for several years now when diving in open water. For cave and wreck, I do use a 7ft hose. I have used Scubapro AIR2s (and other manufacturers' variants of the concept) and even have one on one of my older BCDs. I do not personally use one currently and prefer having a dedicated 2nd stage. I am also an instructor. For open water diving, I much prefer a 40" hose routed under the arm. And while I think there was an earlier argument that a longer hose increased your possibility for entanglement, in my experience, the shorter hose coming over you shoulder is much more likely to get snagged than a 40-44" hose routed under and protected by your arm.
As to what the length of the hose should be, it needs to be long enough to do the job. In open water, this means it needs to be long enough to hold in your hand when you have your arm stretched out in front of you so that you can easily fill a lift bag or safety sausage without putting any strain on the hose. That would also make it long enough to give to your buddy in open water. Keep in mind that in open water you and your buddy will be maintaining contact with each other all the way to the surface. You aren't going to be swimming through any narrow cave passages.
As for swivels and elbows. Both are a compromise between flexibility and airflow. There are two things that affect airflow, changes in direction (corners) and constrictions. Elbows offer a fair amount of flexibility with very little increase in resistance to airflow. The path of the air does make a right angle or near right angle turn, but this does not constrict the diameter of the path that the air travels (unless you have a really cheap elbow). Swivels offer excellent flexibility but at the cost of airflow, first, in terms of changing the direction of the airflow and second, by decreasing the diameter of the tunnel the air follows through the swivel. It is the restricted passage though the swivel that does the most to restrict airflow. The cheaper swivels seem to do more to restrict breathing than the OMNISwivels. That said, I do know some Public Safety Dive teams that use the OmniSwivel for their Full Face Masks (and Omni is the only company that makes one specifically for the AGA). I have also seen some of the cheaper swivels fall apart in a diver's hand (seen it happen twice). And the one cheap swivel I tried did breath harder that the Omni, using the same 1st and 2nd stage setup. For routing under the arm, the elbow is the cheapest solution with the least change in breathing resistance (to be fair, I cannot tell the difference between with an elbow and without an elbow). As for swivels, they aren't all created equally and there probably some that are as good as the Omniswivel. But, except for the Onmiswivel, you can't tell them apart (If you don't see OmniSwivel stamped on it, it isn't an OmniSwivel). So you don't know what you are getting. Did you just spend $60 on something as good as an Omni, or did you just pay $60 for a $5 swivel that will fall apart after 5 dives?
As to what the length of the hose should be, it needs to be long enough to do the job. In open water, this means it needs to be long enough to hold in your hand when you have your arm stretched out in front of you so that you can easily fill a lift bag or safety sausage without putting any strain on the hose. That would also make it long enough to give to your buddy in open water. Keep in mind that in open water you and your buddy will be maintaining contact with each other all the way to the surface. You aren't going to be swimming through any narrow cave passages.
As for swivels and elbows. Both are a compromise between flexibility and airflow. There are two things that affect airflow, changes in direction (corners) and constrictions. Elbows offer a fair amount of flexibility with very little increase in resistance to airflow. The path of the air does make a right angle or near right angle turn, but this does not constrict the diameter of the path that the air travels (unless you have a really cheap elbow). Swivels offer excellent flexibility but at the cost of airflow, first, in terms of changing the direction of the airflow and second, by decreasing the diameter of the tunnel the air follows through the swivel. It is the restricted passage though the swivel that does the most to restrict airflow. The cheaper swivels seem to do more to restrict breathing than the OMNISwivels. That said, I do know some Public Safety Dive teams that use the OmniSwivel for their Full Face Masks (and Omni is the only company that makes one specifically for the AGA). I have also seen some of the cheaper swivels fall apart in a diver's hand (seen it happen twice). And the one cheap swivel I tried did breath harder that the Omni, using the same 1st and 2nd stage setup. For routing under the arm, the elbow is the cheapest solution with the least change in breathing resistance (to be fair, I cannot tell the difference between with an elbow and without an elbow). As for swivels, they aren't all created equally and there probably some that are as good as the Omniswivel. But, except for the Onmiswivel, you can't tell them apart (If you don't see OmniSwivel stamped on it, it isn't an OmniSwivel). So you don't know what you are getting. Did you just spend $60 on something as good as an Omni, or did you just pay $60 for a $5 swivel that will fall apart after 5 dives?
Since I'm moving into cave diving I switched my ScubaPro Nighthawk BCD out for a BP/wing and a 7ft. primary with bungeed second and I'm glad I did. The longer hose has advantages: (1) it lays flat against the body if properly routed increasing streamlining, (2) it facilitates easier (safer) air sharing through tight passages, (3) it makes swimming easier when sharing gas. Tight passages can happen when you enter a wreck wide enough for two divers side-by-side but want to exit through a narrower opening (ex. tug boat wheelhouse windows). If your buddy runs low on gas it's advantagous to share air while swimming back to the exit point instead of surfacing which might require a long surface swim. Proper gas management eliminates the last point but a long hose gives you more options.
As mentioned already donating your primary is easy to learn. If your second is bungeed it easy to switch to it because it's below your chin and you know it hasn't been dragged through the reef or stowed where it gets snagged or caught when trying to retrieve it. I found the air2 to be convenient but hard to breathe from. Because of the tension on the hose it felt like it was going to pull out of mouth. I had to bite down on the mouthpiece. If I ever go back to the Nighthawk I would still use the bungeed second.
As mentioned already donating your primary is easy to learn. If your second is bungeed it easy to switch to it because it's below your chin and you know it hasn't been dragged through the reef or stowed where it gets snagged or caught when trying to retrieve it. I found the air2 to be convenient but hard to breathe from. Because of the tension on the hose it felt like it was going to pull out of mouth. I had to bite down on the mouthpiece. If I ever go back to the Nighthawk I would still use the bungeed second.
I have to tear into this; with respect:
I have the digital Bench test read outs to prove that this is absolutely false.
The change is minimal enough to not be detected on Scuba Instrument's Digital Bench Test platform.
If your explanation were true, Your 1st stage and 2nd stage would negate this as is their job for something that's not even a mm difference in orfice size. But the matter is there is no narrowing or restriction of orfice size or airflow with Omni Swivels or Angle adapters. The only difference is the angle change, which will not affect airflow perceivable on any analog gauge.
My readouts show that Angle Adapter, Swivel, or no adapters, it's all the same readouts in regards to airflow and Magnehelic.
Swivels that are at a 180 degree angle will, by your definition flow better than an angle adapter.
Their setup is the same, Omni or Generic, and it is simply an orb shaped chamber with a eyeballed-measure same entry/exit orifice size, sealed by orings to keep the pressure from escaping. There is no narrowing of the orfice from the hose connection to the swivel orb.
Without getting into the Air 2, yes, by all means, you may use and feel confident that thousands of other divers use their primary routed under their shoulder on a 36 to 40 inch hose. Or, alternatively, and in keeping with the training supplied by nearly every agency and again used by 99% of all divers, route your octopus under your shoulder on a 36 to 40 inch hose and keep your primary over your shoulder on a 22 to 26 inch hose.
For either configuration, shorter people may prefer a 36, taller a 40 or even longer. The right angle connector is fine and does not cause an issue but I recommend that only if you use the longer hose as primary.
N
waterduck
Contributor
I guess I should say I find it more useful if the longer hose is the primary. It will not cause you any particular harm on a octopus.
N
lamarpaulski
Contributor
I do the exact same thing when buddy-diving and use a yellow hose on primary...would give primary up and use the Air2. However, the extra hose is a bit of a pain/ snag point as I frequently stick my head in grottos so I now use short primary hose when solo-diving. Depends on your diving. Maybe your under the arm routing with ball or right angle adapter and lightly attached, looped or similarly semi-attached primary long hose somewhere onto rt front/underarm of bcd would be good set up - I also find a long hose really dangles too far when not in your mouth or without necklace or clipped or secured somehow with hose-gripper.
undrwater
Contributor
Just switched from a 44" under the arm to a 7'. My 44" was a MiFlex, and would regularly float up over my arm. I think I'd rather have the rubber hose for this purpose.
I had the 7' already, and found it really comfortable.
I had the 7' already, and found it really comfortable.
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