Matching regs on doubles?

[Eric Sedletzky]

Just wondering, why is it mandated that 1st stages exactly match on a set of doubles?
I would think that as long as both sets are of top quality then what's the difference as long as they work.

 

[Gombessa]

Just wondering, why is it mandated that 1st stages exactly match on a set of doubles?
I would think that as long as both sets are of top quality then what's the difference as long as they work.

Mandated? Where so?

 

[DevonDiver]

The obvious benefit is that of inter-changability. One spare parts set. One tools set.

Depending on the regulator/s concerned, there may be benefits with hose routing.

Also, if identical, both regulators would have the same performance characteristics.

 

[Thalassamania]

I must have missed the memo, I've often "mismatched," sometimes for a reason ... to clarify bottom mix and travel mix.

 

[RJP]

I must have missed the memo, I've often "mismatched," sometimes for a reason ... to clarify bottom mix and travel mix.

OP's talking about on a set of manifolded doubles.

 

[Eric Sedletzky]

I must have missed the memo, I've often "mismatched," sometimes for a reason ... to clarify bottom mix and travel mix.

You carry bottom mix and travel mix both in your back gas? Are you isolating your doubles to keep them apart?

 

[Eric Sedletzky]

Mandated? Where so?

When I took some tech classes my instructor wasn't too concerned about having missmatched 1st stages on our doubles, but his instructor was pretty adamant about it. For what reason I'm still trying to understand. There was another thread here on SB that was discussing this topic and some were suggesting that even to have two regs of the same brand but slightly different models, for instance a MK20 and a MK25 teamed up was somehow unacceptable. I'm trying to understand the logic behind this. It seems from what I've gleaned in my travels is that a matched set of first stages is prefferable, and a set of Apex regs is the most prefferable.
I personally don't see a logical reason why let's say an Atomic couldn't be used on one side and a Scubapro MK20 on the other side. Asside of the identical parts issue, I don't see how there could be any safety or performance issues with miss matched regs in any brand that is rated for this type of diving..

 

[elan]

My guess would be that each reg has it's own properties and having 2 regs with different properties would require more thinking and accounting for them. One thing would be servicing them.
Not sure if it matters much but that's how that can be logically explained.

 

[Gombessa]

It seems from what I've gleaned in my travels is that a matched set of first stages is prefferable, and a set of Apex regs is the most prefferable.

Well there's a huge difference between mandated and preferable, and I think many have answered the question on the latter. I've looked through the GUE/UTD equipment configuration pages and standards manuals and can't find anything that suggests first stages be the same. I see a lot of Apeks and Scubapro regs on doubles (including some mismatches) but I don't know of any collective preference for one brand over another that's not a regional thing (Apeks may be cheaper in the UK, etc.).

 

[Thalassamania]

You carry bottom mix and travel mix both in your back gas? Are you isolating your doubles to keep them apart?

Independent doubles with a 40 of backup bottom mix and of oxygen.