Sidemounts and Manifolds

[Reg Braithwaite]

I don't cave dive, so this question sprang fully-formed from a vast pool of ignorance on the subject. But in a thread about a PADI Side-mounting Distinctive Specialty, somebody mentioned that side-mounted tanks are always independent doubles.

My question is, what prevents a side-mounter from hooking up a manifold using an extension hose, something like the doo-hickey Halcyon uses for bailout with its RB-80? Are there some massive disadvantages for using an extension hose? Is it that any cave with restrictions tight enough for side-mounting necessitates removing the tanks at some point? Is the hose too vulnerable to entanglements or rupture?

Just curious, really. But has this been tried and found wanting??

 

[LiteHedded]

from what I've heard, the reason is that if you get jammed in a restriction you won't be able to remove the tank

 

[ianr33]

One of the big advantages of sidemount is that the tanks are completely,100% independant.It is impossible for one failure to lead to loss of all gas. Join them together in some way and you lose that advantage.

 

[rjack321]

I don't cave dive, so this question sprang fully-formed from a vast pool of ignorance on the subject. But in a thread about a PADI Side-mounting Distinctive Specialty, somebody mentioned that side-mounted tanks are always independent doubles.

PADI has a sidemount class wt*f for??

what prevents a side-mounter from hooking up a manifold using an extension hose, something like the doo-hickey Halcyon uses for bailout with its RB-80?

Nothing, but what issue are you attempting to address with this flexible hose?

 

[SuPrBuGmAn]

I know of atleast one person who's using a block and quick disconnects that act as a manifold, but also allow for the hoses to be disconnected without a gas loss.

 

[battles2a5]

As others have stated, part of the beauty of sidemount is that it is truly redundant, unlike manifolded doubles. So there's really no need to join the tanks since you should never be in a position where you don't have enough gas to get out given the proper gas planning. Manifolds and gas switching blocks would tie the two together and you will lose some of the 1-mount/ no-mount flexibility, although superbugman's friend seems to have that covered (not sure I'd want/need that approach though). Granted, I doubt padi will be teaching superman or no-mount procedures in their OW (***?) sidemount class.

 

[Reg Braithwaite]

PADI has a sidemount class wt*f for??

I believe it's a "distinctive specialty." The deal is that PADI instructors are strongly encouraged to teach a lot of specialties. So, if you are an instructor and there's something you want to teach that isn't part of the standard curriculum, you can design your own curriculum and apply to have it recognized as a "distinctive specialty." Now PADI gets another dollar and your PADI students get it recognized as part of their advanced or master ratings. I think there are a lot of these things, even a Manatee Diver Specialty

So if you teach PADI and perhaps you also teach cavern in your area, you can teach a sidemount distinctive specialty as part of your students' progression towards a proper cave course. Note that I am explaining what I think is going on, not endorsing or criticizing it!

Nothing, but what issue are you attempting to address with this flexible hose?

I was just wondering about the benefit of being able to use the gas in both cylinders if you suffer a failure the requires you to shut one down. With manifolded doubles, if you don't lose the valve and have to isolate, you draw from both cylinders in a balanced manner.

I was thinking that with independent doubles slung, if you lost the functionality of one reg for some reason, you lose the gas from that tank or have to try to swap regs under water.

Are these simply not considerations? Again, just curiosity here, no caves to speak of in Ontario...

 

[Standingbear56]

PADI has a sidemount class wt*f for??

I believe it's a "distinctive specialty." The deal is that PADI instructors are strongly encouraged to teach a lot of specialties. So, if you are an instructor and there's something you want to teach that isn't part of the standard curriculum, you can design your own curriculum and apply to have it recognized as a "distinctive specialty." Now PADI gets another dollar and your PADI students get it recognized as part of their advanced or master ratings. I think there are a lot of these things, even a Manatee Diver Specialty

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Sidemounting is catching on in recreational diving. Besides the advantages sidemounting is traditionally known for, it also enables people with bad backs or injuries to dive doubles where they could not using the traditional back mount configuration. I myself sidemount due to a back injury. Sidemounting is no longer just for cave diving. Hopefully the cave training agencies will follow PADI's lead and allow sidemounting to be taught as a regular class instead of as an advanced cave diving class. That way recreational divers can Put Another Doller In their coffers.

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I was just wondering about the benefit of being able to use the gas in both cylinders if you suffer a failure the requires you to shut one down. With manifolded doubles, if you don't lose the valve and have to isolate, you draw from both cylinders in a balanced manner.

I was thinking that with independent doubles slung, if you lost the functionality of one reg for some reason, you lose the gas from that tank or have to try to swap regs under water.

Are these simply not considerations? Again, just curiosity here, no caves to speak of in Ontario...

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These are considerations. You've already stated the option of swapping regs underwater. 2 other options are 1) utilize H valves and/or 2) a bail out bottle.

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[rjack321]

sidemounting a cavern would be a stretch even for PADI

no caves to speak of in Ontario...

Actually there are quite a few. Mostly sidemount, no vis, solo affairs. Talk to JimC on TDS, he dives them alot.

 

[Reg Braithwaite]

ctually there are quite a few. Mostly sidemount, no vis, solo affairs. Talk to JimC on TDS, he dives them alot.

Generally locations with those characteristics are kept strictly secret from bumbling n00bs like myself. The old hands are sick and tired of squeezing past the carcasses of those who have no business off a leash...

This contrasts with the free and easy spirit amongst mountaineers. The skeletons of those who climbed above their ability level are usually festooned with slings and the femurs make good makeshift protection for wide cracks.