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DA Aquamaster:A 7 ft hose allows the OOA diver to swim behind the donating diver.
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DA Aquamaster:The use of a 7 ft "long hose" originated in technical diving circles. The idea was to allow air sharing while swimming for a significant distance along the bottom to an ascent line or exit point and even more critically out of a wreck or cave where two divers may not be able to swim side by side. A 7 ft hose allows the OOA diver to swim behind the donating diver.
Long hose use clearly calls for donating the primary in an OOA situation. So it's use in recreational diving is a bit controversial as most recreational agencies teach divers to keep their primary regulator and donate an octopus. In the real world however a semi-panicky OOA diver is far more likely to skip the air share signal business and is more likely to just grab their buddy's primary as it is making bubbles and they want their own bubble making capacity right now. Panic aside, from a practical standpoint, it also makes sense to donate the primary as it is in operation and at worst will only need to be cleared of water rather than potentially sand, gravel, or plant matter.
The traditional recreational agency argument for donating the octo is that it is almost always on a longer hose than the primary (36" compared to 22 to 26") and allows a bit more freedom of movement in ascent. This argument is obviously no longer valid when the diver is using a 5 to 7 ft long hose primary. But there is a lot of institutional inertia involved and instructors and training agencies are slow to change long established practices.
Divers tend to be more open minded though, and in my experience, every recreational diver with whom I have practiced an air share on a long hose was very impressed with the ease it adds to that particular procedure and thought it was a great idea. In tech training, I have found it allows essentially normal activity and have shared with a buddy for extended periods of time to the point where you practically forget they are there.
"Long" hose lenght is also more variable for recreatioanl divers. A 7 ft hose allows the hose to be routed under a hip mounted cannister light, making it the lenght of preference for most technical divers. However the extra lenght can be a problem for recreational divers so they may go with a shorter long hose of 5 ft or 6 ft in lenght. A 5 ft hose routes nicely under the arm on a smaller diver while a 6 ft hose may be needed for a larger diver. A 7 ft hose can also still be used and can be tucked under a waist strap or weight belt if a back inflate BC is used, but is a bit more problematic with a regular jacket style BC.
You can do a search for long hose threads as well as for threads debating the "dontate the primary versus octo" debate for more information and potentially differing opinions.
It's been 20 years since I took an OW course, about 10 years for my spouse and 6 years for my son. All three courses used the "donate the octo approach" to air sharing. 1 for the reasons listed above that Air 2's were used in the course and the other two could have been local/regional thing with PADI and SSI instructors in the area. Or it could be that the accepted norm may finally be changing. Either way it's good news to see more instuctors teaching students to donate the primary.BCS:Hi DA,
Not trying to stir things up...just curious, as you may know something that I am missing or have not come across. But I instruct for PADI (and GUE), and I teach to donate the reg one is breathing for a number of reasons. But I have seen many open water instructors from most of the biggest agencies (NAUI, SSI, PADI) donate the reg they're breathing and even during my PADI IDC the course director used an AIR II and donated his primary. I can't recall anything in the standards (I haven't gotten off my lazy a-- and looked either though) that would cause me to believe that the octo is recommended, but I am curious, is there something I am missing in the RSTC standards that leans towards donating an octo? I may very well have missed something. Or is this something peculiar to another agency?
Thanks DA.
dive safe!--brando
Rick Inman:The few shops that we have around here tend to teach primary or octo donation based on the gear they're trying to peddle.
As to your question, another benefit of the 7' hose is that it lays snug against your body instead of looping out where all manner of stuff can get caught in it.