Long hose or octopus?
How you donate gas to an out-of-air diver affects how you both get out. The long-hose method dominates technical diving, but it's not the only option.
Read this first Information, not instruction. Nothing here replaces training with a qualified instructor.
In recreational diving, the usual way to share gas is an octopus: a spare second stage on a short hose, often bright yellow. In technical diving, the long hose has become the norm. The difference comes down to what happens after the donation.
Gas sharing
How should you donate gas?
Two ways to give an out-of-air diver something to breathe.
Long-hose primary donate
You breathe from a regulator on a long hose, typically 2.1 m (7 ft). In an emergency, you hand over the regulator in your mouth and switch to a backup on a necklace under your chin.
Why divers choose itThe out-of-air diver gets a regulator that's definitely working. The long hose lets divers swim single file through restrictions or along a wreck.
Watch out forNeeds practice to route and deploy cleanly. A long hose can snag if it's not stowed well.
Octopus or short-hose spare
A spare second stage on a standard-length hose, clipped to your chest.
Why divers choose itFamiliar from recreational training. Simple, and you keep your own primary.
Watch out forThe spare may not have been breathed since the dive started and could be clogged or flooded. The short hose forces divers to stay side by side, which doesn't work in narrow spaces.
Why the long hose took over
Cave divers found that sharing gas while swimming side by side was dangerous in narrow passages. A long hose lets the out-of-air diver swim in front or behind. Donating the regulator you're already breathing from also means the other diver gets one you know works.
The necklaced backup regulator sits just under your chin, where you can take it without looking or using your hands much.
Routing the long hose
There are several common routings. In backmount, the long hose usually runs down from the right post, under the right arm or behind a canister light, across the chest and around the back of the neck to the mouth. In sidemount, divers often use a shorter long hose, around 1.5 m or longer, depending on the environment.
Whatever routing you choose, it needs to deploy smoothly, without catching on anything, when you're handing it over in poor visibility.
In open water
Some open-water technical divers use a shorter long hose, often around 1.5 m, because they're unlikely to swim single file. Others keep 2.1 m everywhere so their configuration never changes. Both are reasonable, and it's worth knowing which your team uses.
Practice
- Practise donating your primary without looking, then swimming together.
- Practise receiving gas too, including switching from your own backup to your buddy's long hose.
- Include sharing gas during ascents and at decompression stops.
- Check your backup regulator breathes properly before every dive.