Primary and Octo Hose Lengths

[divinh]

From my experience so far, it seems the idea is to have a short Primary hose and a long Octo hose to hand off for a buddy's out-of-air situation. However, reading more and more here, especially with backplate-wing setups, it seems like the Primary should be long and Octo short because in an out-of-air situation, you buddy might not be thinking straight and go for your Primary, which necessitates for it to be the longer hose. What's the current school of thought on this?

 

[divinh]

Oops, please move to Regulators section...

 

[tbone1004]

most on this forum believe in primary donate as you have undoubtedly read. That includes technical and recreational divers.
Secondary should be as short as reasonable, but typically 20-22", and the primary is still a bit of contention. You can start playing with this setup simply by swapping your existing primary and secondary hoses

 

[rhwestfall]

Choose a way and do it right... Mixed teams should discuss this or-dive.

 

[rongoodman]

The rationale for primary donate is to ensure that the stressed OOA diver is given a regulator known to be working and providing the appropriate gas. The longer primary hose length flows out of that, since you don't necessarily want him right up in your face after you get him on your regulator. I have a 5' primary on my recreational reg set. Cave and wreck divers generally prefer a longer hose, usually 7', since they might be forced to exit single file while sharing gas.

 

[Colliam7]

Tom really hits the nail on the head. The overarching issue is whether a diver chooses primary or alternate donation. And, there is not universal acceptance of one over the other.

After that choice is made, the hose lengths are chosen to fit the diver's preference. Over the years, I became a very definite advocate of primary donation, and I have set up my recreational rig much like my technical rig, with a fairly long (7') primary hose and a short alternate hose (22") that allows me to position my alternate just below my chin on a bungee necklace. I also have a reg set up with a 40" primary and a 32" alternate hose, which I like to use for pool teaching (I happened to have a regulator with those hose lengths so all I had to do was change hose positions on the first stage, add a 70 degree fixed angle adapter to the - now - primary hose, and put a bungee necklace on the - now - alternate).

One reason that I like a 7' hose on my recreational reg is that I like diving with my wife, but I use more air than she does, so we usually end up sharing air - from her cylinder - during a dive to maximize our mutual dive time. Using a 7' hose is great, and allows us far more freedom of movement than a 40" hose does.

 

[Bubblesong]

One reason that I like a 7' hose on my recreational reg is that I like diving with my wife, but I use more air than she does, so we usually end up sharing air - from her cylinder - during a dive to maximize our mutual dive time. Using a 7' hose is great, and allows us far more freedom of movement than a 40" hose does.

Have you considered getting a bigger tank than your wife, to match bigger air consumption? Be more comfortable.

 

[flyboy08]

Oh boy...another what oil should I use thread.....lol

 

[Colliam7]

Have you considered getting a bigger tank than your wife, to match bigger air consumption? Be more comfortable.

My wife chooses to dive only in warm tropical waters, which means almost exclusively AL80s. My personal cylinders are steel 100s , 120s, and 130s, and various doubles. But, they don't travel with us to the Caribbean.

We could also match if she dove a AL63 and I dove an AL80. But, it would be silly for her to go in with 17cf less, when we can equalize by sharing air from the second 80 and both have a longer dive.

Using a 7' hose to share air is actually quite comfortable. And, that is part of my point. A 7' hose is not just useful for sharing air in confined spaces. It works very nicely in recreational diving as well.

 

[Colliam7]

Oh boy...another what oil should I use thread.....lol

Yeah, possibly an element of that is present. But, I think newer divers, or divers trying to further refine their kit, often are looking for some starting point. Frequently, divers buy their first regulator from a shop and don't even question the configuration, nor the hose lengths. And, they end up with the 'standard' lengths - ~36" primary and a 40" alternate. So, I am glad that a user is asking the question, because it may cause reraders to actually think about what lengths work best for them.

As I mentioned before, I think the key is to decide on the desired functional configuration (primary or alternate donation) first, after which the choice of hose lengths is simpler.