does anyone carry second spg

[s7595]

hi all
as I advance in my training and look forward to getting a cave cert in about 18 months .I have looked at the gear setup ,2 tanks,2 regs, long hose ,bungee second around neck, gas managment wich I allready practise. after talking with a couple of instructors telling me storys about there spg failing showing 1000-1400 psi take a breath and nothing.
so if your in a cave watching your guages and time and your buddy is also why not an extra spg to conferm you have air
personly I am strongly considering adding one to my apex reg
sorry for long post

 

[dweeb]

so if your in a cave watching your guages and time and your buddy is also why not an extra spg to conferm you have air personly I am strongly considering adding one to my apex reg sorry for long post

One rationale offered for not having a second SPG is that it is different from the other components. A second stage allows you to breathe, the bladder in a wing keeps you from sinking, etc., but an SPG just furnishes information. What do you do with that information? You make decisions based on it. Once any equipment component fails, the dominant thinking is you abort the dive as quickly as possible - there's only one decision. Hence, if the SPG fails, its decision support role is effectively eliminated.

Of course, your example of an SPG failing and the diver not knowing it militates for having two of them, but then the purpose is to confirm each other's proper function, i.e. to detect, rather than respond to a failure. As such, it's a different type of reasoning that leads to seeing the need for it, which is why it's not as common a practice.

 

[WaterDawg]

I think the more you dive the more you get to know yur own breathing rate if I've been down for 50mins on a single 80 there is no way that
A: I would still have 1500psi
or
B:that my bud would still have 1500psi
If it did we would be close to the NDL anyways and would be ending the dive.

If a HP hose burst your in serious trouble, so having two of them would double that particular risk, ALso having to ck 2 SPG's (to verify each other) would suck. Keep your gear in good reapair and the chances of that happening are LOW.

If you decide that for some reason you NEED this consider getting an air integrated wrist comp and an SPG so you avoid adding task loading and a clumsey second SPG. I would not other wise recomend a air inegrated wrst comp.

 

[Mako Mark]

I carry a spare SPG in my spares kit, it has saved me a couple of times from cancelling a cave dive when the O ring on the swivel has ripped.

It also allows me to change from imperial to metric depending on my dive buddy.

 

[MikeFerrara]

hi all
after talking with a couple of instructors telling me storys about there spg failing showing 1000-1400 psi take a breath and nothing.

Was it cave instructors who told you those stories? I sure hope not.
As some one else mentioned you should have an idea how fast you burn gas but by checking the SPG on a regular basis you'll know if it stops registering anyway.

 

[Dan Gibson]

I always thought LP hoses dump air quicker. The HP port on a reg restricts flow. The size of the opening is a pinhole.

If a HP hose burst your in serious trouble, so having two of them would double that particular risk, ALso having to ck 2 SPG's (to verify each other) would suck. Keep your gear in good reapair and the chances of that happening are LOW.

 

[perpet1]

hi all
as I advance in my training and look forward to getting a cave cert in about 18 months .I have looked at the gear setup ,2 tanks,2 regs, long hose ,bungee second around neck, gas managment wich I allready practise. after talking with a couple of instructors telling me storys about there spg failing showing 1000-1400 psi take a breath and nothing.
so if your in a cave watching your guages and time and your buddy is also why not an extra spg to conferm you have air
personly I am strongly considering adding one to my apex reg
sorry for long post

I recommend talking to the cave instructor you are going to use to see what they recommend and/or require.

As for a pressure guage being that far out of calibration.... If you can not notice that early in the dive (early enough to abort the dive) then you have no business in a cave. Also, if this is such a problem then would you not think that a redundant SPG would be standard equipment for all diving. The reality is that this is a pretty reliable piece of equipment. The failures I have seen have been obvious and did not sneak up on anyone.

 

[samsp]

How reliable are the hosless Air Integrated computers? I could see carrying a small machanical SPG in case that fails. It negates the one less hose argument, but would give some level of redundency.

Sam

 

[s7595]

as for the storys ,one instrutor does not teach cave but is full cave, his spg failed at 200' never found out if he was in ocean or cave, the other was in ocean at 70' lobster hunting and buddy was a litte far so she did a cesa ,thanks for input everyone

 

[The Kraken]

Dive with an Oceanic DataMax Pro-Plus 2, carry a compact SPG/DG as back up on short hose tucked along the left side of my lift bladder.