DIR compliant regulator?

[RTodd]

On deep dives with high helium mixes (where anything breathes well) and on OW dives where the time on the backup reg and stress would be fairly low for more experienced divers there used to be a preference for "crappy" backup regs because they didn't free flow every time you bumped them or the prop wash hit them.

However, for a newer diver probably just go with two of the same. Piston SP Mk25 G250 for diaphragm Apex DS4 TX50. There are plenty of others that will do fine but if you just want them listed for you those are the two most common.

As for taking them apart, you really do want to be able to do that. Keep in mind this stuff scales up. Putting up with a reg that is breathing poorly because the diaphragm has something stuffed in it is no big deal on a relatively short OW dive. It can royally suck and is worth being able to easily fix on a 4 hour exposure such as a deep ocean dive or long cave dive where it is one of the regs you will be spending significant time on..

 

[DIR-Atlanta]

I have personally only ever had to take a second stage apart on two occasions during a dive, but in both cases it made the difference between continuing the dive and aborting.

Once was on a cave dive at Twin Cave in Marianna, where my buddy and I had canoed over with our gear fully assembled and no easy way to go back for tools or spares. Everything tested fine at the boat launch, but when I jumped in the water at the dive site, one of my second stages started acting up, and I had to effect a field repair on the spot. The other time was at the start of an OW dive in the Bahamas, where I purge tested my backup, only to have the purge button stick, causing a continuous freeflow. I stopped it by unscrewing the cover and working the purge until I unstuck whatever was in there. In both those cases I was able to continue the dive without incident, and also without getting out of the water to fix the problem.

So needless to say, I am kind of a fan of being able to unscrew the cover without tools. It's not something you will need to do often, but in cases where you do, it is a nice option to have.

 

[DA Aquamaster]

Don't get too hung up on the book. Most people are not using balanced/unbalanced 2nd stages as described (anymore). I happen to, but mostly because I bought mine long ago.

Exactly, as I stated it made some sense when the G250 or G200 could be paired with the nearly identical except unbalanced but still high performance G200. Now it is much less comon to be able to find a high performance second stage from any manufacturer that is unbalanced.

And in the distant past the politics and driving personalities of DIR and Scubapro aligned to a great degree so basing reg choice on availabel SP options was not uncommon. Then they had a falling out, it mattered a lot less what SP sold.

 

[DA Aquamaster]

I have personally only ever had to take a second stage apart on two occasions during a dive, but in both cases it made the difference between continuing the dive and aborting.

Once was on a cave dive at Twin Cave in Marianna, where my buddy and I had canoed over with our gear fully assembled and no easy way to go back for tools or spares. Everything tested fine at the boat launch, but when I jumped in the water at the dive site, one of my second stages started acting up, and I had to effect a field repair on the spot. The other time was at the start of an OW dive in the Bahamas, where I purge tested my backup, only to have the purge button stick, causing a continuous freeflow. I stopped it by unscrewing the cover and working the purge until I unstuck whatever was in there. In both those cases I was able to continue the dive without incident, and also without getting out of the water to fix the problem.

So needless to say, I am kind of a fan of being able to unscrew the cover without tools. It's not something you will need to do often, but in cases where you do, it is a nice option to have.

To each his own but personally, I am not sure I would have started a dive with a potentially faulty reg givne that the problem was evident on the surface.

I would have done more or less the same thing, but I would have also popped the purge button and spring out and inspected to ensure wahtever caused the problem was no longer there - even if it meant climbing back out of the water for a couple minutes for any needed disassembly or adjustment. I'd prefer my buddy took the cautious approach too as it is my reserve gas he has on his back that is at risk if a fault occurs again later in the dive.

If something similar were to happen during the dive, an abort is in order. I can live without completing whatever dive it is I am doing that day, as long as I am prudent and live to come back to do it again another day. So in effect, if a diver makes an underwater repair and then pushes on with the dive rather than abort, some divers would argue that diver is on a fairly slipperly slope where a combination of being goal oriented and willing to accept excessive risks may get him or her or their team in trouble when one small problem becomes part of a longer chain of problems leading to an accident.

 

[ShagMan]

I have personally only ever had to take a second stage apart on two occasions during a dive, but in both cases it made the difference between continuing the dive and aborting.

Ditto, I don't even have that many dives, have already experienced this... had a reg with a hunk of debris that had found its way to the exhaust diaphram... being able to take off the cover and extracate it was the difference between calling the dive (2 hour boat trip) or fixing it and getting the dive in.