HOW TO: SET UP A TWINSET - PART 5: REGULATORS

The information below is based on how I dive and how my equipment is configured (unless teaching where agency standards dictate otherwise), however other methods are available.

Overview

On my previous blogs we’ve discussed a Hogarthian setup, chosen and setup twin cylinders (here), wings (here) a one-piece harness and backplate (here) and a suit inflation cylinder (here).  Now we’ll discuss regulator configuration.

This article will differ slightly from my previous ones as I will discuss both Primary Donate (Hogarthian/DIR) and Secondary Take (BSAC).  Equipment configuration is such a varied and topical subject, and in particular regulator configurations make up a large part of this.

Happy reading.

Regulator Choice

The majority of regulators used by technical divers seem to be either Apeks, Scubapro, Halcyon and more recently Tecline.  Manufacturers are also designing regulators with technical divers in mind with features such as first stages which offer better hose routing or second stages that can be configered left or right handed.  Although personally I am an Apeks fan there are a number of factors when considering which regulator is best for you:

·     What other regulators do you/your team/your buddy use?  If all regulators are from the same manufacturer, and of a similar model, faults can be much more easily fixed on the spot as the odds are higher that there will be a compatible spare in your kit/within the group.

·     What regulators does your instructor use and more importantly why?  Don’t just blindly follow.

·     The most expensive regulators are not always the ones you need to buy.  For example do you need to pay extra for a regulator that can be configured left or right handed?  On the primary donate example below you do not.

·     Test any new configeration in a sheltered water environment first.

·     And finally, regardless of what regulators, or configuration you select, remember to keep the hose routing streamlined.  It gives the diver easier access to the cylinder valves if required and ensures nothing protrudes that could impact or snag with the outside environment.

Termonalogy

Below are a few terms that may be unfamiliar which will appear later on in this post:

·   Right post.  The right cylinder valve behind the divers head as they wear them.  This can also be known as the primary post as all the primary equipment is connected to it.  This is because this cylinder valve will ‘roll on’ (see below) therefore all of the primary equipment will always be working.

·     Left post.  The left cylinder valve behind the divers head as they wear them.  This can also be known as the backup or secondary post.

·     Roll on.  Based on forward propulsion, the cylinder valve would roll (turn) on if it were to make contact with an overhead environment (see diagram).

·     Roll off.  Based on forward propulsion, the cylinder valve would roll (turn) off if it were to make contact with an overhead environment.

·  Primary regulator.  The one that the diver is breathing during normal diving.

·  Backup regulator.  The one that is not being breathed.  The ‘backup’.  Usually located under the divers chin.  In recreational terms this can be known as alternate source (AS), alternate air source (AAS) or octopus.

·     OOG.  Out of gas.  Sometimes referred to out off air. 

Why the Long Hose

“A long hose is for technical divers.  I’m still doing recreational diving, but I want to stay down a bit longer.”

Personally I’m a fan of the use of the long hose (primary donate) at ALL levels of diving as it has a number of advantages.  Most boat skippers (or holiday dive guides) insist of ascending up a shot line or a DSMB.  If not, it’s still good practice to as it ensures there is no surface traffic above.  In an OOG situation, where you’re face to face with your buddy, with little room, it is going to be extremely difficult, and stressful, to deploy a DSMB.  The advantage a long hose brings is it gives added distance between the 2 divers, increasing comfort and reducing stress levels. 

A long hose also has advantages in an overhead environment when exiting, even at recreational wreck diving level.   As an example, the Scylla in Plymouth is one of the most popular wrecks in the UK.  With depths ranging from 14-23m it sits within recreational levels.  However if one were to have an OOG situation inside, despite the multitude of exits, swimming out whilst adopting the traditional AS would be a struggle.

“I’ll have a long hose on my AS.  That’s ok isn’t it?”

Most training agencies configure recreational divers with an AS clipped off somewhere within the ‘triangle of access’ which the OOG then takes, and this method works fine for the majority of divers.  Fast forward to a trimix diver who is carrying a number of stage/decompression cylinders.  Despite divers carrying out a buddy check before diving, an OOG diver may be panicking, and with a number of regulators in view, may accidently take the wrong one.  This could mean attempting to breathe from an empty regulator (cylinder turned off), or (accidently) breathing from a regulator that contains a poisonous gas mix (for that depth).  And even if the OOG diver takes the correct regulator, it could be ‘rolled off’.  By donating the regulator in your mouth, the OOG diver knows he is getting a. a working regulator and b. one which is safe to breathe.  You then simply go to your backup (under your chin).  Even if this has ‘rolled off’ you can calmly turn it back on instantly. 

“But I don’t carry stage cylinders.”

Even if you don’t carry additional cylinders, by having the AS in a clip, on a breakaway, or even in a necklace under your chin can cause delays in the OOG diver receiving it.  First you have to locate it (doesn’t apply to a necklace).  Is the AS hanging where you expect it to be?  Has it come off?  Then disconnect it, and then donate it to the diver (if they haven’t already taken it).  An easy task on the surface that can become more difficult if stress is involved.

What if the OOG diver takes the regulator from your mouth, without warning?  The same situation applies as you need to locate, disconnect and replace your AS, but now you may be panicking as well.

For all of the above reasons, my preferred configuration is primary donate.  There is an argument against this method as it means both divers, for a split second, do not have a working regulator in their mouth.  Agreed.  But it is only a split second, and the pros out way the cons in my opinion. 

“What length hose should I use?”

Traditionally 5ft/1.5m and 7ft/2.1m hoses are available.  I would always choose the 7ft/2.1m hose for 2 reasons:

Video screenshot of an OOG scenario
on my Cave course

·  When swimming out of a narrow overhead environment, a 5ft/1.5m hose is not long enough for 2 divers to swim out one behind the other.

Long hose tucked behind canister

 on a single cylinder setup

·     A 5ft/1.5m hose is not long enough to be stowed around the divers body neatly using a ‘hog loop’ (Hogarthian/DIR).  Although this method can be used, the hose is free to move and potentially either snag, or ride up behind the divers head.  By using a 7ft/2.1m hose, it can either be secured inside the waistband of the harness or tucked under the primary light canister.

Long Hose Stowage

“So where do we store this long hose?” 

We mentioned on one of the earlier paragraphs about keeping our hoses streamlined to ensure access to the cylinder valves and to remove snag hazards.  It also needs to be easily deployed and re-stowed.  This gives us 2 options; hog loop or bungee.

In my first twinset blog (here) I briefly covered the Hogarthian setup, what is DIR and William Hogarth Main.  In this configuration the long hose goes under the divers left arm, secured inside the waistband of the harness or tucked under the primary light canister (depending on hose length), across the body, around the back of the divers head and feeding into the divers mouth from their right hand side.  To deploy, simply grab the regulator hose with an over grasp grip, pass it forward to the OOG diver briefly ducking your head, all in a single movement.  Only then once the hose is clear can you go to your backup regulator.  Once the OOG diver has the regulator and is breathing, you can either deploy the remainder of the hose from inside the waistband of the harness or tucked under the primary light canister, or try and fix the problem.  Re-stowing the regulator after use is the reverse of deployment.  This method has the advantage that it will always deploy.  The only thing the diver needs to be aware of is their drysuit hose or primary light cable, which can trap the hose if not properly checked.

Continuous loop

When bungeeing the long hose (either primary donate or secondary take), it can either be done on the wing (if it has bungees) or on the cylinders.  I have found the latter the most popular.  I have tried 2 different methods, a continuous loop and a horseshoe.  My personal opinion is that the horseshoe gives a much smoother deployment, and helps prevent snagging, as if the hose not stowed with care, the continious loop can snag on itself and not deploy (see picture).  This disadvantage means that it is impossible to guarantee deployment until it is required.  There is also the disadvantage that bungeeing the long hose require 2 divers to re-stow it after use, for example switching onto a stage/decompression cylinder.  It also means that S-drills are often skipped pre-dive.

Horseshoe

Snag

SPG – 1 or 2?

“So how many SPGs should I have?”

Sometime I see people with 2x SPGs and when I ask them why there is never a strong argument, with answers such as “That’s what I was taught” and “If I have a failure I still know how much gas I have left”.  Unfortunately the former shows a poor understanding of the divers equipment.  With regards to the latter, providing correct gas planning was carried out prior to the dive, as long as no team member broke the rule of thirds, there is sufficient gas left to exit the water.  No additional SPG is required. 

By only having 1x SPG routed on the left post it brings the diver many advantages:

·     More streamlined and less chance of a snag.

·     Less failure points.

·     Allows the diver to look at it whilst using a spool/reel or a DPV (these are right handed operations).

·     Allows problem solving.  Lets look at this more closely:

·     Closed isolator valve.  Because the SPG is on the left post (see below), if the isolator valve is closed the cylinder pressure will not drop, indicating this problem.

·     Closed left post.  Either, the cylinder pressure will not drop, or, the SPG will read low or empty as the backup regulator loses pressure, again indicating this problem. 

·     These problems may be missed if the diver is looking at an SPG coming off the right post.

Equipment List

To have you regulators set up in the configurations below you will need the following:
1. 2x regulator first stages.

2. 2x regulator second stages.

3. 1x 7ft/2.1m low pressure regulator hose (as per the reasoning above).

4. 1x 22”/24” (depending on body size and regulator type) low pressure regulator hose.

5. 1x 22” low pressure wing hose (plus 2 strips of innertube if not already on the corrugated hose).

6. 1x 26” low pressure drysuit hose (if not using a suit inflation cylinder – blog here).

7. 1x 24” high pressure SPG hose.

8. 1x SPG.  Usually the boot or console is removed as these are heavy, can drag underneath the diver and damage the environment.

9. 1x necklace as per my blog here.

10. 2x p-clips/bolt snaps and cave line as per my blog here.  

Primary Donate

Below is my configuration as per a Hogarthian/DIR setup.  Before I explain what goes where, lets go recap some of the reasonings behind the configeration.  If we start with the long hose, based on primary donate and the ‘roll on’ principle, this is connected to the right post, meaning the backup regulator is connected to the left post.  Our primary buoyancy is the wing so this is connected to our right post, so our drysuit (which can be used as reserve buoyancy) is connected to the left post.  Finally, as reasoned above, the SPG is connected to the left post.  Below we will discuss the routing in much more detail.

Right Post:

·     Primary regulator.  This is connected into the rear most port on my first stage (Apeks DS4) as it naturally routes the hose downwards.  The hose then runs down the back of the wing and is hog looped as per my previous statement.  Finally a p-clip/boltsnap is added at the end of the hose so that it can be clipped off onto the right should d-ring when not in use.

·     Wing hose.  This is connected onto the front port on my first stage as it angles the hose forward slightly.  The hose then runs behind the divers head and down the corrugated hose.  It is secured into position on the corrugated hose by 2 strips of innertube.  The LPI is secured into the harness by a large O-ring/bungee loop on the left shoulder d-ring as per my blog here.  Some divers prefer to have wing hose running directly off the left post reasoning it is more streamlined and much simplier.  I admit that I used to do this, however another reason for having the hose come off the right post is if the diver had a failure in the schrader valve, resulting in the wing automatically inflating.  If this failure were to occur, you could simply disconnect the hose from the LPI, but by this point positive buoyancy will have occurred which could result in an unplanned ascent.  Instead, by shutting off the right post and dumping from the left kidney dump on the wing, buoyancy can be maintained.  Once the valve is completely turned off, switch to the backup regulator and try to resolve the problem.  If you were to configure your wing hose on the left post your drysuit hose should be swapped over to this port.

Left post:

·     Backup regulator.  This is connected into the rear most port on my first stage as it naturally routes the hose down.  The hose then runs behind the divers head (some divers prefer to have it running under the corrugated hose), around the right hand side, and is secured in a necklace under the divers chin.  Although previously I mentioned that this hose should be 22”/24” long, to check it’s the correct length, with the regulator in the divers mouth it should not drop off the right shoulder, and when looking left it should not pull out of the divers mouth.  When kitting up this must be placed on before the primary regulator so that it sits underneath and does not restrict the donation movement.  Some divers prefer to have the regulator fed over the left shoulder if the regulator can be configured that way, again reasoning it is more streamlined and simpler. I have also done this.  For this method to be streamlined, you would require an extremely short hose.  By having the backup regulator routed over the right shoulder, you reduce the snag hazard, and maintain similarity across all second stages (primary, backup, and stage/decompression).

·     Drysuit hose (if not using a suit inflation cylinder or wetsuit).  This is connected onto the front port on my first stage as it angles the hose forward slightly. The hose then runs under the left arm, inside the harness (to prevent trapping the backup light) and is connected to the drysuit.  When kitting up this should be placed on first so it sits underneath the long hose and does not restrict the donation movement.

·     SPG.  This runs down the divers left side, close to the body, and is clipped to the left hip d-ring by a p-clip/boltsnap.  Some divers prefer to have this clipped off on their left shoulder d-ring as it makes it easier to see.  I prefer not to, as a. you should only be confirming what you think your SPG should be reading, and b. once you add stage/decompression cylinders, the left shoulder d-ring becomes very cluttered and has a number of SPGs there.  Some divers then add “I’ll move it down when I start carrying stage/decompression cylinders”.  In addition to learning this new skill, they have to learn to clip off the SPG in its new position, which is now slightly more awkward as there is a cylinder there.  By clipping the SPG off on the left hip d-ring from the start the diver builds muscle memory.

Secondary Take

In 2009, the British Sub-Aqua Club (BSAC) released a clarification statement on Alternative Supply training and going diving (link).  In summary, it said that BSAC’s policy is “to teach a simple consistent method for dealing with an out of gas situation for a buddy. That system should be consistent with the most common method taught worldwide and workable with all types of equipment configuration. BSAC aims to maintain consistency throughout its training courses and its safety advice to members.”  Because BSAC teach secondary take across all levels it does not support the teaching of primary donate as it is not compatable with their policy.  With regards to diving within a branch, they do go on to say “divers who have been taught alternative methods through other training agencies are not banned from using those techniques within BSAC”.  Although I understand with BSAC’s reasoning, (in my opinion) they have managed to alienate themselves within the technical diving community. 

If we think back to Primary Donate we started off with the long hose (primary regulator).  Lets again start here.  Should the long hose (AS) be connected to the right post so it always ‘rolls on’, or should it be connected to the left (backup) post?

When required to do so, below is the configeration I believe works best:

Right Post:

·     Primary regulator.  The primary regulator, this time on the short hose, connects as per my previous statement.  It would arguably be better to have the backup regulator (AS), this time on the long hose, attached to this post so it never ‘rolls off’, BUT, when dealing with failures, the standardisation of the right post remaining the primary is key, especially when muscle memory kicks in.  As before, a p-clip/boltsnap is added at the end of the hose so that it can be clipped off onto the right should d-ring when not in use.

·     Wing hose.  No change.

Left post:

·     Backup regulator.  The backup regulator, this time on the long hose, connects as per my previous statement.  It is then bungeed to my left cylinder in the Horseshoe method as previously shown and is secured in a necklace under the divers chin.  For this method to work, you will require a regulator that is reversible such as the Apeks XTX series.  Some divers have this clipped off if they do not have a reversible regulator, but I do not like this as a necklace has the advantage of being instantly assessable to the diver in an emergency.  You’ll need to find it fast so it’s important you know exactly where it is.   

·     Drysuit hose.  No change.

·     SPG.  No change.

Finally

The explanations and pictures above are based on Apeks DS4/XTX series regulators.  If you have another model first stage, or regulators from another manufacturer, the orientation of the hoses may change slightly however the principle is the same.  A few final thoughts are:

·     Ensure you have spare hoses of the correct length.  Ideally per diver but if not per team.

·     The hose lengths listed are very specific, especially the low pressure hoses.  If you have existing hoses, why not shorten them as per here.

·     All the hose protectors have been removed as they can hinder hose routing and hide hose damage.

·      When not in use, the long hose is always clipped off on the right shoulder d-ring with the hose tied in an overhand knot.  This prevents the hose snagging during transit and the second stage falling from the dive platform onto the floor and getting damaged.

I hope you enjoyed this article and no doubt some of the above will create some discussion. The above 2 configurations are how I dive, and are the result of many different configurations, in the same way as my back plate, wing and harness setup.  But I have an open mind and am happy to discuss any configuration questions you may have.  Lastly, regardless of which method you decide to use on your own equipment, always get formal training from a qualified instructor.

The boring bit!

All opinions expressed in my articles are my own and may differ to other instructor’s and agency guidelines; by no means are they wrong and I would not wish to disrepute any of them.  This article is for information only and should not replace proper training.

Safe diving!

Timothy Gort

BSAC, PADI & SDI/TDI diver training

l Mob: 07968148261 l Email: tim@rectotec.co.uk l