Sidemount - why only one long hose?

[KerrenL]

Hi, genuine question here. Will be doing SM training soon and I'm sure they'll answer this, but I'm curious as to the population's input.

Reg config on SM (from what I can tell) follows a similar pattern to primary donate config, i.e. one short and one long hose. I understand this on primary donate as it's well proven that most panicking divers will grab the reg in your mouth as they know it's working. However, on SM you switch regs fairly often so you will spend (theoretically) at least half of the dive with a short hosed reg in your mouth - which a panicking diver would likely try to take and would cause issue due to hose length.

Therefore my question is, why are both hoses not long, with one being kept strapped to the tank and able to be pulled free if needed, the other could be routed in the normal way, or indeed kept strapped to the tank and just clipped off to a D?

Thanks in advance!

 

[Rilelen]

The long hose setup really evolved in cave diving, where the purpose of the long hose isn't to prevent a panicked diver from ripping the reg out of your mouth, but to allow you to share gas in passages that may require you to move single-file down a passage (that is, one in front of the other).

Sidemount diving also evolved in caves, and "borrowed" the short hose/long hose conventions from backmount doubles. There's no reason for this other than consistency across rigs. Notably, some sidemount divers historically have advocated for not using a long hose in sidemount at all, because in theory a team of all-SM divers should all be self-sufficient in managing even a catastrophic loss of gas, since you can feather your valve/switch to fully independent tank & valve, etc.

In short: the purpose of the long hose isn't to control a panicking a diver (although it may help, as a side effect). You can still donate your long hose, even if you aren't actively breathing off it the moment another diver is in need of it - both second stages should be readily accessible to you.

 

[KerrenL]

Ok, that's interesting thank you. So it's not necessarily "designed" but has just come about this way - yes, get the need for long hose for cave diving. You make an interesting point about the ability to swap the donor reg over once the panicked diver has calmed so they can use the long hose. This of course is a sensible option!

Yes, if with groups of SM divers then each should have their own redundancy, but I guess if you're diving with someone with twins and they have a major issue / or other random scenarios.

Is there a good reason why SM setup couldn't be two long hoses both tucked into the tank bands? Or just goes against convention?

 

[rjack321]

Some people do dive with 2 long-ish hoses. Probably the most popular variant there is 2x 5ft hoses

 

[Mobulai]

I believe some SM divers actually use 2 long hoses (but probably 5‘ not 7‘)

 

[JohnN]

Ok, that's interesting thank you. So it's not necessarily "designed" but has just come about this way - yes, get the need for long hose for cave diving. You make an interesting point about the ability to swap the donor reg over once the panicked diver has calmed so they can use the long hose. This of course is a sensible option!

Yes, if with groups of SM divers then each should have their own redundancy, but I guess if you're diving with someone with twins and they have a major issue / or other random scenarios.

Is there a good reason why SM setup couldn't be two long hoses both tucked into the tank bands? Or just goes against convention?

The long hose is typically wrapped around your neck, not tucked into tank bands. You're welcome to use whatever configuration works for you, but a short hose on the right tank clipped to the right D ring works best for me.

 

[Mobulai]

Beat me by a second

 

[The Chairman]

I dive SM with 2 5-foot hoses.

 

[Mobulai]

I gotta say sometimes I hyperbole that I’d have a gas hemorrhage in my long hose tank, AND would have an OOG buddy and I can’t donate the longhose
Far shot, I might try the 2x5 hose thing and see if I’m comfortable there
But a good valve drill skill should also mitigate that risk

 

[KerrenL]

Ok, so if I'm plotting for all worst case scenarios, two long hoses (maybe with one 7' for cave dives) maybe a way to go. Interesting. Ta