Safety stop deco bottle

[Blackwood]

I would think the only need for a stage bottle would be in an air leakage problem, or an oog situation.

A stage bottle is used to extend bottom time.

 

[diver 85]

I've never heard of this. Can you even suck air out of a second stage at depth if the first stage is on the surface? That doesn't seem possible; don't both stages have to be close to the same ambient pressure for the system to work?

Back to the original post - I've never used hang bottles, not at 130' at the Blue Hole, not at 90' at my NAUI AOW class deep dives - never.

Yes, here's a pic from last summer in Little Cayman of a 2nd stage hooked to a topside boat tank @ the 15' depth...1st time I ran across this was in Grand Cayman in early '86 @ Spanich Cove Resort......

 

[String]

Seen some operators abroad use them. Generally caters for holiday style divers with lower than average skills so more likely to be low on gas. In rough seas the things swing around waiting to break masks,noses or other limbs if it hits a diver who gets too close.

Not used here as no dives end with a return to the boat - if you think you need it you take it with you on the dive and not rely on something just being there if you get back to the boat.

 

[foles1972]

I once had a regulator failure on a 100 foot wreck dive. I was able to get my buddies attention and we shared his air while doing a normal ascent. Now I generally use a pony bottle on dives over 60 feet, and I sling it from my BC. A pony bottle won't be any use to you if it is 60, 70, or 80 feet above you on the anchor line.

I do not, however, use the extra air on a normal dive. Emergencies only.

 

[MikeFerrara]

This should be a good thread! Thanks for bringing it up.
I have never heard of that before, but it definitely makes sense. I would think the only need for a stage bottle would be in an air leakage problem, or an oog situation. Does anyone have any reasons why this would NOT be useful, other than the bother of bringing along a stage bottle?

The reason that it isn't very useful is that there isn't any reason to be certain that youll be coming up that line.

We do leave stage and decompression gas behind in a cave when we know that we're coming back the same way we went in or aren't comming back at all.

In OW, you best carry any gas you think you'll need. That includes stage gas, decompression gas and any other emergency gas.

 

[DA Aquamaster]

I agree with Mike, but that is a very tech answer. The truth is the average diver on the boat is recreationally OW or AOW trained and is not equipped to deal with the results of the extra 5 minutes they just spent on the bottom, in a current or with a freeflow on their single tank and no pony system.

In that case, having a bottle hanging at 20' may mean the difference between the diver having a safety stop or not. It's cheap insurance for an average trained and average prepared diver and even if it does not come up with the diver they can still save the gas in they have left in the tank for a normal ascent and inflate at the surface or can come up with a buddy.

 

[MikeFerrara]

I agree with Mike, but that is a very tech answer. The truth is the average diver on the boat is recreationally OW or AOW trained and is not equipped to deal with the results of the extra 5 minutes they just spent on the bottom, in a current or with a freeflow on their single tank and no pony system.

I don't really disagree but if they aren't trained or prepared for the problems they are liable to run into, maybe they're diving beyond their training/experience in the first place?

As I see it, without redundancy and the skill/training to use it and you're best to dive shallow enough that the surface is your backup.

In that case, having a bottle hanging at 20' may mean the difference between the diver having a safety stop or not. It's cheap insurance for an average trained and average prepared diver and even if it does not come up with the diver they can still save the gas in they have left in the tank for a normal ascent and inflate at the surface or can come up with a buddy.

It doesn't hurt to have it there but it might not help either.

 

[Blackwood]

... the average diver on the boat is recreationally OW or AOW trained and is not equipped to deal with the results of the extra 5 minutes they just spent on the bottom...
[snip]
In that case, having a bottle hanging at 20' may mean the difference between the diver having a safety stop or not.

...If they find it. I don't boat dive very often, but it always seems that when I do many of the divers surface everywhere but near the boat.



Is it reasonable to assume that the diver who doesn't have the presence of mind to navigate back to the boat is the same diver who isn't equipped to deal with problems on the bottom?

 

[Colliam7]

Saw a bottle (with 2 second stages) hung at 20' on a charter of the NC coast several years ago. I no longer recall which charter operator it was, but haven't seen one hung by any other operator since. Seemed like an interesting idea, and I recall seeing several people use it, possibly just to try it out.

 

[Boxcar Overkill]

This seems like such a clever solution for a problem that doesn't really exist that much for your average rec diver.