One of the questions I hear most often when I dive with new people is some version of the one above: Why do you use such a long second stage hose?

The curiosity is natural. I use an almost six-foot-long hose between my first stage (the one that attaches to the tank valve) and my primary second stage (the regulator mouthpiece that I breathe from). And to make things even weirder, my secondary second stage (the backup regulator mouthpiece, or octopus) is on a very short hose, meaning it doesn’t reach down like it does on most divers. Rather, it attaches to my BCD.

Note: When I teach entry-level dive courses, I switch to a more common setup, as I need to demonstrate how to recover the regulator and use the octopus, so I only use this setup on my own dives, and for advanced courses.

So to the average open water diver, this set up does indeed look a bit strange. But there’s a good reason for it.

The origin of the long second stage hose

The setup I use originates from twin-tank setups, and indeed, that’s where I use it most often. I also have it on my single-tank setup from time to time. Cave and wreck divers used it originally, as the long hose allowed them share air in case of an out-of-gas situation. These divers would refer to what they breathed as “gas,” rather than “air,” as they often used gas mixes other than atmospheric air, while still swimming single file in cramped spaces. The octopus hung in a bungee-cord necklace around the neck. That way, if your buddy experienced an out-of-gas situation, you’d donate the primary regulator and switch to your secondary. The hose itself wrapped around the diver’s torso to keep their profile streamlined. This setup also allowed the diver to quickly deploy the regulator.

The long hose as a general setup

So why do you see divers (including me) use the long-hose setup on dives that aren’t in caves or wrecks? The decision comes from the realization that there are a number of advantages to the setup; first and foremost, a diver who runs out of gas is often in a state of panic, or at least severe stress, so they are unlikely to respond in a cool and calm manner. In fact, oxygen-starved divers often simply grab the first regulator they see. That regulator is usually the one in their buddy’s mouth. Second, a regulator that has just been used (as in seconds before) is pretty much guaranteed to work.

A regulator that you tested before the dive, but hasn’t been used since, might have developed a problem, however unlikely that is. And when a diver runs out of gas, it usually takes them some time to get their buddy’s attention and get their regulator. This means they’ll be oxygen-starved, maybe critically so. So if you’re going to hand them a regulator, best to hand them the one that you absolutely know for certain will work.

So this is the main reason a number of divers have adopted the long-hose configuration even for open-water dives with a single-tank setup. Add to this the benefit of having the same setup at all times, regardless of where and with what number of tanks you’re diving, and you’ve got a good argument for the long hose.