New to DH - questions on safety or reliability when using DH setup

[sidemount]

My understanding is that the modern octo's purpose is to make buddy breathing easy, and is generally unnecessary and was only introduced by the first cave/solo divers in case their primary reg failed (and they had it on a separate tank so it was relevant?). It does just attach to the same air source. I also understand making the octo a requirement is a great way to sell the same thing twice and is a point of contention in some circles...

In the highly unlikely event that your DH regulator fails, you just have to go to a buddy to buddy breathe (or will it fail "open" and freeflow 99.99% of the time?). Is this correct? i.e. 99.99% of the time, I'm diving a rental tank in really easy conditions (>78deg water, <150ft depth, swim throughs only). If I buy a DH regulator "ready to go" and completely overhauled, and keep it in pristine condition, will I ever have to abort a dive due to reg failure and do a CESA if I can't find my buddy? I suppose I can just turn the tank off and remove the regulator, and just breathe off the free flow directly from the tank if that's the case. Will I need to bring a second DH rig or modern reg when I travel to keep my wife from being able to say "I told you not to buy that old crap"? If so I'll be bummed - I'm hoping to hear these things are absolutely bullet-proof since they were used by the Navy for like 50 years, and not having to carry an octo in my carry-on bag will save me a lot of space.

Thanks in advance!

 

[herman]

. forget about stopping your wife from nagging, that's not going to happen.

SO, first off, there are basically 2 types of DH regs, single stage and 2 stage. With the single stage (USD Mistral, Voit 50 Fathom,Healthways and others) you do not have an option of an octo since there is no IP. Tank pressure is reduced directly to ambient. You must resort to buddy breathing for OOA. Many DH divers prefer the simplicity of the single stage, I would not suggest it for a first DH and esp not a travel reg. It's not elegant but the Mistral is considered the AK-47 of the vintage regs, it works under almost any abuse.

With 2 stage regs (USD DA Aquamaster and Royal Aquamaster and the Voit equlivants you have some options. First off, you can add a octo to the hookah port of these regs, giving you an octo if you like. Or IMO a better option is to upgrade a DA to a Phoenix which will open up a lot of options for you, more on that shortly.

There are a lot of "issues" when diving with a DH hose that you may not be considering. When DH regs were in common use, SPGs, BCs and octos were not standard diving equipment like today and most DH regs simply do not have provisions for them. For gas management, you have to use a J valve tank (almost unheard of in rental tanks today) or the later addition, a banjo. A banjo is a device that goes between your tank and the reg, providing you a sampling port for you tank pressure. In addition to no octo, you also do not have any source of air for BC inflators. This requires you to either orally inflate or forgo the BC altogether (my preferred option). These differences bring with them a lot of issues. Diving with unknown buddies, you really need an octo. Not for you but for them because they will have no clue how to buddy breath (with an octo, it's share air not BB). Then there are the issues with dive ops. Show up with no BC, no SPG and no octo and most will not know what to do, many of them will not allow you to dive.

My solution is to carry a fully tricked out Phoenix. With it I have a SPG, an octo and a LP inflator hose so I can gear up with all the modern bits and pieces to make the dive op happy and/or to keep the gear somewhat familiar to an insta buddy- although a "how my stuff works" conversation is important. If I am diving with know buddies and if the dive op is agreeable to it, I drop the bits I don't need. I typically dive a Phoenix with just a SPG, no octo or BC. While on the subject, modern BCs do not work well with DH regs so plan on changing BCs as well.

As for safety, a restored and properly maintained DH reg (USD or Voit- parts for the rest are not really available) is just as reliable as a modern reg. Fact is, the internal parts of a Royal Aquamaster are the exact same ones in a AL Titan or Conshelf. Freeflows are handled the same way as with a modern reg, just keep breathing from the mouthpiece, any excess air will just be vented out the exhaust. The failure modes are pretty much the same as is the likely hood of having problems. No reg is 100% reliable but a restored DH is no more likely to fail than a modern reg. From a personal safety standpoint, I trust my DH just as much as my Apeks, from an unknown buddy standpoint, not so much.

Bottom line, a DH will in all likely hood increase your gear amount, not reduce it. Besides being physically larger, the hoses take up a good bit of room, to meet the requirements of many dive ops you will need to carry BCs,Octos and the rest of the modern bits and pieces anyway. Then on top of all that, you will have to learn to dive a DH reg, just connecting it to a tank and BC does not cut it. That is a fairly long discussion in itself. For what it's worth, I always carry a modern first and second stage in my checked baggage just in case I run into a totally unreasonable dive op that will not allow my DH reguardless of how it's configured. I just swap the SPG, LP inflator and octo off the Phoenix, dive and then find a different op.

 

[Bob DBF]

. forget about stopping your wife from nagging, that's not going to happen.

It's going to take a while to get all the coffee out of the keyboard.

There is a third option for SPG for personal use. There are a number of old J and K valves that have a HP port on the valve itself.

I dive with an LDS on occation and show off the DH. On these trips I carry a pony and add an inflater hose for the wing to keep the instructor happy. And lets face it, if a diver trained today had an OOA and was offered a double hose to buddy breathe it would not be pretty.


Bob
-------------------
I may be old, but I&#8217;m not dead yet.

 

[captain]

If the issue of BC, SPG and octo are removed from the equation the reliability is increased because all those things add failure points to the system. The double hose regulator is more reliable than a single hose simply because of its simplicity. Only one O ring in the system at the tank to regulator connection, no hoses at above ambient pressure to rupture. The only realistic failure mode is the diver himself.
If you want to become a better diver learn to dive a two hose without the need for all the add ons. The add ons are for convenience not safety.

 

[simonbeans]

Herman
Be sure to copy and paste your reply in your files on your computer so that you can return to your explanation for the next newbie. Nice job.
I would only add one item and that would be for newbies to go to Vintage Scuba - Vintage Scuba Gear at Vintage Double Hose and search/ask there where the majority of DH divers group.
As for this: And lets face it, if a diver trained today had an OOA and was offered a double hose to buddy breathe it would not be pretty.

My buddy and I were diving Devil's Den in Grand Cayman. After passing through a small opening, I turned to my buddy to see him searching for his reg which had dropped away from the mouthpiece still in his mouth. I turned, dropped slightly below him, lifted my DH mouthpiece to him. By lifting the mouthpiece above my head, it went into a free flow which cleared it. My buddy took a welcomed breath of air while I retrieved his reg, shoved the mouthpiece back on and continued the dive. He had never dove a DH, never BB on one and it was as pretty a "recovery" as can be. By the way, mouthpieces on a DH are not prone to slip off a 2nd stage like a single hose.

 

[sidemount]

If the issue of BC, SPG and octo are removed from the equation the reliability is increased because all those things add failure points to the system. The double hose regulator is more reliable than a single hose simply because of its simplicity. Only one O ring in the system at the tank to regulator connection, no hoses at above ambient pressure to rupture. The only realistic failure mode is the diver himself.
If you want to become a better diver learn to dive a two hose without the need for all the add ons. The add ons are for convenience not safety.

Excellent!

 

[Sitkadiver]

Sidemount,

I cannot add any more or better information than what Herman already said.

As a new DH guy let me just say though, that you should be patient and take the time to learn how to use it, where to place it on your back and give yourself some dive time with it. They really grow on you though, so don't be surpirsed when you end up with 5 or 6 of them.

You asked about safety and all I can say is that my Pheonix has become my goto reg. I use it all the time. Since I do light commercial work, I use an AGA mask in some of the harbors and around outflow pipes, but the Pheonix has handled everything I've thrown at it so far.

Here are some pics of the regs in action to back up my claims:

This was taken on the way up from 147ft. reg worked great. The second dive that day was to 120ft. but I had to turn around at 110 when my buddy, who was using modern gear, began to run low on air.

I used my other Pheonix to raise a boat a few months ago and had to run a pneumo line off the Pheonix in icy water and had no issues. It breathed great the whole time:

Pulled this up Tuesday while using a DH reg.

Last weekend I used my Phoenix to recover dished from an old WWII dock site. Didn't get photos since the viz was crap, but used a lift bag again. Here are some old photos of the dish dives, this is a New England Divers reg, which is the same as a Sportsways Hydro-Twin, they have 2 LP ports and a HP port on the 1st stage if that makes your life easier - but those regs are hard to find:

If you get a DA Aqua Master, you can get the adaptor for the hookas port in order to run an inflator hose or octopus. This reg came back to life with just a tune up after it had been a wall hanger for 20 years: The guy diving it is our former LDS owner.

Voit Navy's also have a hooka port and are mechanically the same as the DA. I used my Voit Navy to do some zinc work on a crab boat earlier this year and you can see the drysuit inflator hose coming off the hooka port.

All I can conclude with is that DH regs are completely safe. I will be diving mine again tomorrow while I'm working on the Sea Life setting anchor chains and doing underwater video.

 

[sidemount]

Thanks Herman, my hope is to just carry the DH and a banjo/SPG when I travel - no more BC/octo. So I'm not sure I'd need the Phoenix (although the new $50 widget looks cool, and I may need to buy the special tool from you to service it...). I never dive with an operation where I don't know the owner (or can't talk to them on the phone beforehand) so I'm not hyper-concerned about being put out to pasture. And I never get to dive without my wife (!) so the insta-buddy thing doesn't really come up for me either.

Thanks also for the note on reliability compared to Apeks. I think I'm headed towards a Mistral (AK47) instead of the DA Aquamaster (M16) now...

---------- Post added May 4th, 2012 at 01:01 PM ----------

Awesome pics Sitka, thanks! Damn, now I'm thinking it'd be nice to have an extra port in case I do want to dive a BC or throw an octo on there, and I wouldn't have to worry about a separate banjo fitting to keep track of for the SPG...I guess I have to go with the DA Aquamaster to make the Phoenix happen then.

---------- Post added May 4th, 2012 at 01:06 PM ----------

Herman
Be sure to copy and paste your reply in your files on your computer so that you can return to your explanation for the next newbie. Nice job.
I would only add one item and that would be for newbies to go to Vintage Scuba - Vintage Scuba Gear at Vintage Double Hose and search/ask there where the majority of DH divers group.
As for this: And lets face it, if a diver trained today had an OOA and was offered a double hose to buddy breathe it would not be pretty.

My buddy and I were diving Devil's Den in Grand Cayman. After passing through a small opening, I turned to my buddy to see him searching for his reg which had dropped away from the mouthpiece still in his mouth. I turned, dropped slightly below him, lifted my DH mouthpiece to him. By lifting the mouthpiece above my head, it went into a free flow which cleared it. My buddy took a welcomed breath of air while I retrieved his reg, shoved the mouthpiece back on and continued the dive. He had never dove a DH, never BB on one and it was as pretty a "recovery" as can be. By the way, mouthpieces on a DH are not prone to slip off a 2nd stage like a single hose.

Nice! Nothing screams quality like your mouthpiece falling off your regulator while it is in your mouth. Also, I searched both forums and couldn't find this type of "hold my hand" info, maybe a sticky at VDH would be good.

 

[herman]

IMO go with a Phoenix with a small SPG. You can alway remove what you don't want and simply plug the holes and in the event you are forced (or feel you really need one) you can rent/borrow an octo or LP hose. It is the best breathing of the DH regs and since the internal parts are AL Titan, you can find service parts all over the world in the unlikely event you need to repair it.. I carry a spare HP seat and balance chamber orings on every trip...never needed them however.

 

[SwimJim]

The Phoenix is a great addition to any 2 stage USD or Voit DH reg and opens a world of options. My personal recommendation is to read all you can on the use of DH regs and if possible, find someone to mentor you. That would shorten the learning curve a bunch. Vintage Scuba - Vintage Scuba Gear at Vintage Double Hose has tons of info. Go to the main page and you'll see what I'm talking about. I don't know where your from, but theres double hosers all over the place these days. I hail from Wisconsin and if your in my area, pm me and I'll show you the ropes.

Jim