DIR- Generic SPG dir requirements

[DavideShardana]

Hi All.

Question from a newbie. Are there specific requirement for what kind of spg we use in cave diving?

I am still a recreational diver, and with my friend ( GUE instructor) we where having a debate about the type of SPG to be used. It all come out because i have actually a air integrated dive computer (Suunto Cobra 3) since I want to transition to side mount, I really wanted to keep the computer, for the following reason:

1) respect Hoghartian principle regarding carrying less equipment since you have a computer and a spg in one.
2) I was thinking about to buy a second one in this way I have a redundant computer, to be placed on the second tank. I can solo dive easily also.
3) Free your wrist for other equipment.
4) researching on internet (no formal training) I could not find any information about strict requirement

Speaking with my sidemount and cave instructor (not my friend another one), He was not thrilled about the idea and he was almost concerned about streamlining and entanglement hazard.

Your Thought

 

[jborg]

You want a simple brass & glass SPG. A computer on your wrist is fine, there's not that much other equipment you need to put there... DIR in general, and probably especially in cave diving or bigger dives, favours interchangeable equipment. Your computer being screwed into your regset makes it not interchangeable. Air integration loses most of its value when you start carrying and using stages.

 

[DiveLikeAMuppet]

I would go with a simple mechanical SPG.

Your computer belongs on your wrist - you should be able to use it for timing ascents, not sure how would you do that with a computer that you cannot see at all times as it’s attached to one of your tanks on a short hose (sidemount) or clipped to your left D-ring (backmount).

Air integration is not great in terms of building habits - you should get an OCD habit that forces you every 5 minutes to check your runtime and average depth, calculate your expected gas consumption in your head and then check the SPG to confirm it. Not sure if air integration helps with building the habit.

 

[DavideShardana]

Now makes more sense thanks

 

[rongoodman]

What you need to be thinking about is how that proprietary Suunto algorithm is going to work in conjunction with the computers of your team mates. I'm thinking not well.

 

[DiveLikeAMuppet]

What you need to be thinking about is how that proprietary Suunto algorithm is going to work in conjunction with the computers of your team mates. I'm thinking not well.

Something like Suunto Zoop is a brilliant and cheap bottom timer, no problems there... The problem with this console computer is that you cannot put it on your wrist, so it's a bit recreational junk.

 

[Lorenzoid]

https://www.gue.com/standards-appendix

"The first stage must also supply an analog pressure gauge ...."

This is GUE's standard, but I would guess most divers who dive DIR-style similarly tend to stick with an analog SPG.

To me, the old "brass and glass" gauge is fun. Steampunk dive gear!

 

[AJ]

What you need to be thinking about is how that proprietary Suunto algorithm is going to work in conjunction with the computers of your team mates. I'm thinking not well.

Plan your dive, dive your plan. It does'nt matter what the computer says, the team is diving the plan or we're not going to dive anyway. A problem with Suunto computers is that they like to decide for you what's the best deco strategy. This may be different than your team plan, with the risk of being locked out by the computer.

https://www.gue.com/standards-appendix

"The first stage must also supply an analog pressure gauge ...."

This is GUE's standard, but I would guess most divers who dive DIR-style similarly tend to stick with an analog SPG.

To me, the old "brass and glass" gauge is fun. Steampunk dive gear!

AI is creeping into the DIR world also I dive AI only on my CCR. D12 I dive with AI (convenient) and SPG ( old habit).

AI is more reliable and precise than SPG imo. One advantage of AI is, when it craps out you will know it. An SPG can give you false information. Hence first the guestimation first, then confirm the expected gas pressure at the SPG. If they differ too much, abort the dive because you know you have enough gas to reach the surface, but you don't know how much exactly.

In the end: it does'nt matter how do it, as long as it's safe.

 

[Lorenzoid]

AI is creeping into the DIR world also I dive AI only on my CCR. D12 I dive with AI (convenient) and SPG ( old habit).

AI is more reliable and precise than SPG imo. One advantage of AI is, when it craps out you will know it. An SPG can give you false information. Hence first the guestimation first, then confirm the expected gas pressure at the SPG. If they differ too much, abort the dive because you know you have enough gas to reach the surface, but you don't know how much exactly.

All true. I was simply pointing out that GUE's standards continue to specify an analog gauge, and many divers continue to prefer them (some, like me, for a completely subjective, non-technical reason).

 

[PfcAJ]

Plan your dive, dive your plan. It does'nt matter what the computer says, the team is diving the plan or we're not going to dive anyway.

Eh…if you have a tool, use it. If the computer spits out something different than what you expect, you should investigate why and make an educated choice on if to follow it or not.