Spare air or pony

[Thalassamania]

Spare airs are great ... for escaping from helicopters that go down over water. Besides ... shame on you ... spearfishing is properly done freediving.<G>

 

[Diver Dennis]

As a continuation of the other thread, I just spent 3 months diving in Asia and except for diving doubles in the Philippines, I saw no one diving any type of redundant air supply in any of the countries I visited.

 

[Gary D.]

Well, if you happen to have one, I say put it in your car (you drive off a bridge) or in your nightstand in case your house fills up with smoke. They must be good for something. I thought the Marines used them to get out of submerged helicopters?

Agreed, but now we are outside of the diving realm where that thing belongs.

Nothing will replace good gas management or good training, especially a Spare Air which some want to use as a crutch.

Gary D.

 

[neil]

57 breaths is way optimistiic. I got 12 big breaths from one , calmly standing in a nice warm dive shop. Besides the inadequate size factor, the regulator is a finicky POS, IMO. Never owned one, but I used to repair them.

 

[divad]

I've always heard that the crappy regulator are prone to leaking, so they're not even very good to have under your car seat.

 

[Cheekymonkey]

I have also heard that over time they will empty out evad and you have to always fill them recently before needed.

But for you crazy spearfishing scuba diving types I'd suggest something big after seeing some of you boys chase things a little deeper or longer than you should have. A 40CF seems big but you'll hardly notice in the water.

 

[String]

Lets just rehash the maths on this thread as well (its been done before but im bored).

Spare air "300" contains 85 litres of air.

Average person normally breathes 20 or so litres a minute (unstressed).

On the surface that will give you about 4 minutes of air.

Assuming a typical lung capacity is 6 litres its 14 breaths.

Take that down to 10m/30ft and you have 2 minutes of air, 7 breathes

20m / 60ft - 1 minute 20 seconds or 4.5 breaths.

Note thats assuming a roughly NORMAL breathing rate. Now assume the person is stressed. SACs double and in some cases quadruple during these periods.

Assuming a rather modest doubling (Oh ***** im out of air and oh ***** ive got a tiny tiny tank to get me to the surface). At 30ft thats going to give you 1 minute or air at most.

Basically for any depth > 30ft the thing isnt going to get you up to the surface utilising a safe ascent rate and definately not with any sort of safety stop.

The "old faithful" as the website laughable calls it is even worse. 48 litres

2 minutes of air on the surface, 1 minute of air at 30ft assuming a normal breathing rate. 4 breaths at 30ft. Double the SAC due to a problem and youre talking seconds maximum. Not even enough to get up safely from 30ft with a sane ascent rate.

 

[Cheekymonkey]

String if your assumptions are right it probably takes more time to stick it in your mouth than its worth breathing out of at 60ft

 

[String]

Just saw this on their website that made me laugh

Surface Breaths* 57
Water Volume 26.62 cu in / .42 liters

*Based on 1.6 liters per breath

1.6 litres per breath?! Not even an infant has that low a lung volume.

Average person breathing normally uses 3.5 to 4. A full lung is about 6.

The nitrox version is really really making me laugh. Yeah 20 seconds of a nitrox mix will make a REAL difference to the no doubt rapid ascent you just had because you were stupid enough to get OOA with no backup.

 

[mthirsc]

I'm going on a liveaboard trip to Saba and St. Kit's this spring. I understand that there will be a number of 100+ foot dives around Saba. Ideally, I would be doing them in doubles, but since they won't be available, I'm planning on taking along a 19cf pony to sling.

Have you considered independent doubles? They are one solution in a situation like that and have the advatage of increasing your total supply while also giving you the redundancy you need, and can be thrown together with 2 rental 80's very easily.