cyclingman
Registered
My sidemount setup uses a central isolatable manifold (UTD setup), so the 2nd stage configuration is identical to back mount - donatable long hose, backup on a necklace & short hose.
Sidemount - why only one long hose?
- Thread starter KerrenL
- Start date
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PEDiver
Contributor
I'm sorry but that setup completely negates the advantages of SM as a whole - namely, the ability to have completely redundant tanks. If you want to mimic a BM configuration, just use a 7' hose on the right and a short hose on a necklace on the left. The UTD setup just adds additional failure points and tries to solve an issue that doesn't exist in the first place.
cyclingman
Registered
For diving in confined spaces, I get that. But wrecks and caves etc aren't the only reasons for sidemount. (I should emphasize that I'm not a technical diver, not tech or cave certified, and not any kind of instructor.)
Diver-Drex
Contributor
Two 5’s, both run down the cylinders and seconds clipped on chest D rings. At first it mattered to me to replicate BM doubles for familiarity. At this point I have enough dives n both co figuration it doesn’t matter. I can transition back and forth dive to dive.
The SDI/TDI Sidemount Manual, ISBN: 1-931451-93-1, 2016 edition, shows two long hoses on page 60. It is a valid configuration within the SDI/TDI philosophy. The advantage is that you can always fine-tune the regulator hose by pulling it back under the tank band or loosen it to reduce stress or pull on your mouthpiece. This is in comparison to the short hose, as it took me a while to find out which length fits me best.
The disadvantage is that one long hose has to run straight up from the tank to your mouth. Otherwise you would have two long hoses running around your neck and you cannot quickly donate the second stage that is below the other. The benefit of running the hose around the neck is that you can easily free half of the hose length just by nodding your head. Pulling the remaining hose length out of the tank bands is step #2, when the diver in distress is already breathing from your tank. In consequence, when you want to donate the regulator that comes straight up, you need to pull the hose out of the tank bands immediately. That's not impossible, but a bit more difficult.
Another point to consider: Depending on your choice which second stage runs straight up, you might need a left-handed second stage, or a model that is convertible.
In Sidemount, donating the regulator you are breathing from is not that important. We switch regulators multiple times a dive, so we always proof that both regs are working. This is different from Recreational Diving, where the octopus is often used as an anchor or plough to stir up the sand / silt. For me in Sidemount, a long hose and a short hose is absolutely fine. In mixed teams (BM + SM), sharing a common standard (i.e. long hose coming at right hand side) makes out-of-gas drills more easy. But again, anything goes.
The disadvantage is that one long hose has to run straight up from the tank to your mouth. Otherwise you would have two long hoses running around your neck and you cannot quickly donate the second stage that is below the other. The benefit of running the hose around the neck is that you can easily free half of the hose length just by nodding your head. Pulling the remaining hose length out of the tank bands is step #2, when the diver in distress is already breathing from your tank. In consequence, when you want to donate the regulator that comes straight up, you need to pull the hose out of the tank bands immediately. That's not impossible, but a bit more difficult.
Another point to consider: Depending on your choice which second stage runs straight up, you might need a left-handed second stage, or a model that is convertible.
In Sidemount, donating the regulator you are breathing from is not that important. We switch regulators multiple times a dive, so we always proof that both regs are working. This is different from Recreational Diving, where the octopus is often used as an anchor or plough to stir up the sand / silt. For me in Sidemount, a long hose and a short hose is absolutely fine. In mixed teams (BM + SM), sharing a common standard (i.e. long hose coming at right hand side) makes out-of-gas drills more easy. But again, anything goes.
Issue with swapping between long hoses is they can become twisted around each other behind the neck.
With the standard long on boltsnap (setup to release with a tug) and short on necklace that isn't a factor.
With the standard long on boltsnap (setup to release with a tug) and short on necklace that isn't a factor.
As a consequence of the switch timing, odds are that you will be on the long hose when there's an OOG event, both at the beginning (when someone's valve is off) and at the end (all their gas is used up). This is also the case when the other diver is on a single tank.
For example, using AL80s, it's typical to switch at 500 psi increments (leapfrogged). The first ~13 cuft are on the long hose, the next 27 are on the short hose, and the long hose is again in use from a cumulative 40 cuft to 53 cuft. That's the equivalent of 2000 cuft out of a single AL80, and most DM-led dive groups are ending the dive about then. If you're in a position to be mugged by an OOG single-tank diver, just stay on the long hose once you get back on it.
For example, using AL80s, it's typical to switch at 500 psi increments (leapfrogged). The first ~13 cuft are on the long hose, the next 27 are on the short hose, and the long hose is again in use from a cumulative 40 cuft to 53 cuft. That's the equivalent of 2000 cuft out of a single AL80, and most DM-led dive groups are ending the dive about then. If you're in a position to be mugged by an OOG single-tank diver, just stay on the long hose once you get back on it.
To tag along with inquis:
I try to be on long hose at the beginning and end of all dives with other divers around me or in a team. Only downside is when scooting it's slightly harder to feel the long hose freeflow but still very noticeable.
I try to be on long hose at the beginning and end of all dives with other divers around me or in a team. Only downside is when scooting it's slightly harder to feel the long hose freeflow but still very noticeable.
Diver-Drex
Contributor
I do not put ether hose around my neck. I don’t see the point as the hose is well managed under the tank bands. I can donate either hose, they aren’t getting tangled and it doesn’t matter which reg I’m on.
The other advantage of two long hoses is if you end up shutting down your right post in BM, you have nothing to share because all you have is the short hose. In SM with two long hoses, I can shut down a tank and still be able to buddy breath or to let a buddy use if I’m on a deco gas.
The other advantage of two long hoses is if you end up shutting down your right post in BM, you have nothing to share because all you have is the short hose. In SM with two long hoses, I can shut down a tank and still be able to buddy breath or to let a buddy use if I’m on a deco gas.
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