Category Archives: Equipment

MC90 mCCR – Dive buddy perspective

This past Tuesday, I dove with Andrew and the new UTD MC90 mCCR.

Since its announcement to the world, it’s caused more than a few amusing posts on Internet forums. The comments ranged from interested, to wait and see, to let’s give the MC90 a chance, to WTF are these guys thinking.

Like any configuration, I assume that it has its plus and minuses. And for what it’s designed for, I bet it meets its needs. Since I don’t do deep expedition in remote locations, I’m not the best judge of success. However, there are a few aspects of the MC90 that I do appreciate:

  • Similar protocols to OC – I like the similarities of handling issues from OOG to rock bottom. I’m sure the consistency is nice for those who dive both rebreathers and OC, but I also like it for the ability to dive in mixed teams. I don’t want to miss a dive because I don’t have a rebreather.
  • Gas extension – Not unique to the MC90, but I’ve always been fascinated by the recycling aspects of rebreathers. Lower gas usage and lower costs (in the long run) are intriguing.
  • Variable P02 set points – Hadn’t thought about this till we spoke about rebreathers on the drive down to Monterey. Current models and decompression schedules are based on changes in pressure and the P02 of the gases breathed at specific depths. The ability to change P02 at any depth opens up a lot of possibilities for decompression diving.

Find more videos like this on Unified Team Diving

Hog looping – misinformation about the Hogarthian configuration

This week, BSAC’s “Technical Group Leader” sent a message to their technical instructor corp regarding BSAC’s position that the hogarthian configuration should not be taught.

While BSAC has prerogative to make any ruling on gear configuration or teaching methods and philosophy, it’s the misinformation about the Hogarthian gear configuration and the OOA procedure that’s unforgivable.

As the result, their decision has caused a justifiable stir on the Internet:

Below is the message originally sent to the BSAC technical instructors:

Dec 2009

“Hogarthian rigging” and “Primary take” when teaching “out of gas response” on BSAC courses

Dear BSAC Instructor,

The recent introduction of the BSAC Sports Mixed Gas course and the subsequent automatic upgrading of all Extended Range Diver Instructors with a mixed gas qualification to Sports Mixed Gas Instructor have highlighted a problem. This problem concerns the teaching of “Hogarthian rigging” and “Primary take” within BSAC courses in general and on BSAC Technical courses specifically. Instructors who have qualified via the instructor workshop or observed course routes will be familiar with the BSAC policy regarding these techniques. However, it transpires that many of you who have automatically upgraded from ERD Instructor or those of you who teach within the regular Diver Training Programme (OD, SD, DL & AD) may not. I am therefore taking the opportunity to remove any ambiguity by explaining the BSAC policy and the reasoning behind it.

Definition of terms:

“Primary Donate” is the technique of a donating the demand valve the donor is breathing from to an out of gas casualty, the donor then resorts to his/her alternative gas demand valve.

“Primary Take” is the technique were an out of gas casualty snatches/takes the donors regulator independent of any action by the donor, the donor then has to take up his/her secondary demand valve.

“Hogarthian Rigging” is the technique of routing a long (1.5 metre – 2 metre) primary regulator hose from the cylinder valve, under the right armpit, around the front of the body, around the back of the neck and culminating in the primary dmand valve being the one the diver is breathing from.

BSAC has conducted field trials and as a result have arrived at the conclusion that “Hogarthian rigging” and “Primary Take” are incompatible with techniques taught within BSAC training programmes, do not work efficiently without significant donor input in some circumstances and are incompatible with some equipment types.

BSAC is aware that these techniques are taught and promoted exclusively by one US technical diving agency and favoured by some technical diving instructors from other agencies which, whilst not necessarily promoting it do not proscribe it either. Therefore I would like to take the opportunity to clarify BSAC policy as it is important to ensure you all understand why BSAC has taken a firm position on these particular techniques.

Some instructors from other training agencies teach and promote “Primary take”. This is where the casualty is taught to take the primary demand valve from the donor’s mouth. Incident statistics have indicated that this has the potential to have serious and dangerous consequences. Most divers have not been conditioned to cope with such an event and there is an element of transfer of the problem from casualty to donor within this procedure. Fortunately current incident reports dicate that “Primary Take” is not a common response and most out of gas casualties have resorted to their conditioning by training to give the appropriate signal and accept donation. It can be readily seen however that “primary take” is completely incompatible with rebreathers. For all of these reasons BSAC does not support or allow this technique to be taught by BSAC instructors to BSAC members or on BSAC courses.

“Primary donate” clearly ensures that an out of gas casualty will receive a working demand valve that supplies a breathable gas and if confronted with an out of gas diver the donor will choose whether to donate his/her primary or secondary demand valve. As long as the secondary demand valve is readily and easily accessible and the donor is well practiced in dealing with it this is workable. However, it is worth noting that this is not the only method of ensuring this desirable result. An alternative gas demand valve prominently placed within the triangle of access can achieve this equally well and has the advantage that the donor does not need to remove his/her own regulator and thus possibly exacerbate the problem. This latter is also a system that recreational divers will be conditioned to and familiar with, a benefit in terms of reduced training requirement when moving to upgrade their diving skills but also a system they are familiar with if confronted with an emergency underwater.

BSAC fully approves and supports the use of long hoses (1.5 metres – 2.0metres) to allow freedom of movement between donor and casualty in any out of gas situation. However the question of whether the diver breathes from the long or short hose arises when a long hose is fitted. Divers using independent twin-sets have a dilemma in that they have to swap demand valves at intervals during a dive. Since with independent twin-sets both regulators are in effect primary regulators the only complete solution in this case is to have long hoses on both regulators such that which ever demand valve is donated there is a long hose to facilitate freedom of movement.

In the case of a twin-set fitted with an isolation manifold there is a primary and secondary regulator and many divers employ a long hose on one and a standard hose on the other. The decision as to whether to breathe from the long or standard length hose is defined by whether the diver chooses to adopt primary donate or alternative gas source. However, instructors and divers should consider that swapping demand valves at least once during the dive to prove bothregulators are in full working condition at depth is good practice. Having both regulators fitted with long hoses covers all bases and is worth consideration even with this configuration.

The field trials BSAC conducted with “Hogarthian rigging” revealed a number of issues. The primary and essential criteria when considering hose routing and stowage for the donation demand valve must always be ease and efficiency of deployment covering the widest possible range of deployment situations. Re-stowage is not and cannot be the defining criteria.

“Hogarthian rig” is favoured by some for the simple reason that it is by far the easiest method to restow, the donor can easily re-stow the hose without assistance. An instructor may demonstrate deployment and re-stow a number of times without difficulty. However, re-stowing is of little significance compared to efficiency of deployment. In a real out of gas emergency the out of gas casualty needs a quick, seamless and efficient deployment to facilitate a successful result. Having completed the donation and with the out of gas situation fully resolved it is unlikely that donation will be required again in the dive therefore the hose may then be re-stowed in any convenient way.

Deployment of a Hogarthian rigged demand valve can be problematic in some circumstances. The ideal situation is for both divers to be more or less horizontal and facing each other. In this situation the hose should deploy easily. Where both divers are vertical and facing each other in the water it will be necessary for the donor to rotate forward to facilitate deployment over the head. There is a possibility of dragging the donors mask strap off but this can be avoided by wearing the mask strap underneath the hood. If the casualty approaches from the left side of or from behind however, the donor must quickly rotate forward and to the left to allow deployment of the long hose. If the casualty approaches from below the donor then it is necessary for the donor to roll forwards to facilitate deployment. In these cases the donor has to take significant action to enable the technique to work and this becomes proportionately more of a problem with the level of stress and urgency being experienced by the casualty. BSAC does not advocate that Hogarthian rig cannot be made to work, it is merely that it is a
system that may require significant and speedy action from the donor to ensure it works, without such donor input there is significant potential for snag and pocedure failure.

In contrast an alternative gas demand valve placed within the triangle of access combined with a long hose, stowed carefully under elastic bungees, either on the side of a cylinder or under the elastic ties of a wing or indeed any other method of hose stowage that can be relied upon to deploy efficiently without any action needed by the donor to ensure rapid deployment, works effectively and efficiently in all circumstances and with all equipment types or configurations, including rebreathers. An added benefit of the above system is that all recreational divers will have been trained in the use of alternative gas source. Minimal retraining is required as the only new element is the long hose and method of stowage.

In summary, it is clearly desirable that consistent and uniform emergency response techniques are established. The advantages of adopting a system that is widely taught and understood world wide at recreational level therefore requires minimal reconditioning through training and works efficiently without donor input with all equipment types and configurations are self evident. Therefore on the basis of trials and evidence BSAC has opted to teach as a preferred technique:

1. Alternative demand valve stowed within the triangle of access
2. The donation of a demand valve when required
3. The configuration of a long hose/s stowed in elastic bungees such that it/they will deploy efficiently and seamlessly when required.

This preferred technique does not involve the use of “Hogarthian rigging” or “primary Take”. BSAC standards and policy require that these techniques cannot be taught by BSAC instructors to BSAC members or on BSAC courses. The various BSAC Course Instructor Manuals provide clear guidance on preferred techniques to be taught on BSAC courses.

I hope this has clarified the situation and given an understanding of the reasoning behind it.


Mike Rowley
NDC Technical Group Leader

The Bogaerthian Configuration

While backmount cave divers have mostly adopted the Hogarthian gear configuration, sidemount divers’ kit remain very individualistic. Without commercially available units, each sidemount diver built rigs based on different levels of knowledge and experience, different environmental challenges, different goals, and different ideas on how best to realize them.

In the past, many of the pioneering sidemount divers were dry cavers. As the result, they were comfortable building their own gear and this gear had to work in both the dry and wet sections of a cave.

When there were no readily available units, sidemount divers would either build a system from scratch or adapt an existing non-sidemount specific kit for their needs.

Even with the introduction of commercial systems (see the explosion of systems at DEMA 2009), many sidemount divers choose to modify and extend. This speaks heavily towards a strong individual streak in sidemount divers.

But it could also mean that no one has come up with a holistic gear configuration to meet most sidemount divers’ needs. While the Hogarthian backmount system is common these days, we must remember that it is a relatively recent innovation. Standardization in sidemount configuration is where backmount was 10-15 years ago.

After taking a sidemount course with Steve Bogaerts, I believe that his configuration does provide a holistic and standard system for sidemount divers.

Steve’s gear configuration shares a few key similarities to the Hogarthian backmount rig:

  1. 7′ long hose and shorter 22″-24″ hose, necklaced (“Basic” sidemount configuration).
  2. Single continuous 2″ webbing harness and a crotch strap.
  3. Minimalist approach to dive gear and set-up.

Hose routing
For sidemount divers diving at the basic level or in mixed teams of backmount and sidemount divers, the 7′ long hose and shorter 22″-24″ necklaced hose keeps OOG and gas-sharing protocols almost the same as in the Hogarthian gear. OOG diver receives the long hose, and the donating diver breaths from his short hose.

The difference for sidemount is that the donator may not be breathing the long hose when an OOG situation occurs. However, OOG situations are usually not without advance notice and the divers can plan accordingly. In addition, one breaths the long hose at the beginning and end of the dive, the most likely times of OOG situation.

Routing of the hoses on the sidemount diver is similar as well. The necklace is routed from the left tank, around the back of the neck, and delivers from the right side. The 7′ hose is partially tucked into the right tank’s bands, brought across the chest, around the back of the neck, and delivers from the right side.

When not in use, the 7′ hose is clipped to the right shoulder D-ring, with a breakaway connection. The boltsnap is close to the second stage to prevent dangling, but far enough to allow breathing from the stage without unclipping. If gas sharing may be required, then the long hose should be unclipped in preparation for easy handoff, unless it’s already in the diver’s mouth.

Each tank has an SPG attached to a 6″ HP gauge. The gauge is not tied back up to the first stage and remains flushed against the tank. The handwheels are positioned on the diver’s outside, and the valve stems face inward.

The first stages are faced up (towards the diver) and the SPGs rests on the tank. When the sidemount bungees are attached to the tanks, they rotate 45 degrees placing the handwheel in the armpit and the SPG between the tank and the diver’s body. This reduces entanglement and keeps the gear streamlined. To view gas, the diver flips the gauge up from the outside.

It is important to note that sidemount tanks should be considered your primary tanks, and set-up should not be confused with stage tanks and stage tank configurations.

After a couple of years of field trials, Steve’s harness is complete. He has dubbed it the “Razor Harness.”

Unlike the other sidemount harnesses currently available, the Razor is extremely minimalistic – A single 2″ webbing harness, a separate crotch strap, and two small stainless steel plates to give the harness shape. To hold the neck of the sidemount tanks, the Razor has one continuous bungee with a bolt snap on each end. Custom sized D-rings and two special tri-glide with an attached D-rings complete the harness.

Each shoulder contains a 1″ D-ring. The smaller D-ring minimizes movement of gear, and is the attachment point for the bungee and stages. In addition, they also function as a temporary work space, similar to backmount. When not using a helmet, I attach my backup lights to the shoulder D-rings as well.

The bungee is an in-water replaceable unit and is attached to the shoulder D-rings with a small bolt snap on each end. The custom length allows it to be as tight as possible, keeping the sidemount tanks secure to the body.

A primary cutting device is attached to the waist. Or Steve’s preference of the wrist.

Waist D-rings on the side of the body secure the bottom of the sidemount tanks. This is similar to carrying a stage in a backmount set-up. The significant difference is the Razor uses small 1/2″ D-rings. These very low profile D-rings reduce tank movement as it limits the distance between tank and diver. In addition, the bolt snap position on the sidemount tanks is different than a stage tank, and this further reduces tank movement.

Additional low profile D-rings are positioned between the hip and diver’s midpoint. These are used to secure butt light tanks in a horizontal position when they start to float. In reviewing other sidemount harnesses, the Razor is the only harness that has this feature.

Weights are threaded on the harness, generally on the back waist or on the back center piece. If more heads down trim is required, then weights can be placed on the shoulder straps where they exit the Razor’s Delta Shoulder Plate. The diver is weighted to be neutral in water, without tanks. Tanks are kept streamlined, and no weights are attached to tanks.

When the weights are back waist mounted, then triglides with small D-rings (Drop Attachment Points) help lock the weights in place. However, if position of weights makes DAPs location non ideal, then regular tri-glides may be used.

The Bogaerthian method mounts a detachable flat pouch to the DAPs. The pouch contains backup safety items as well as wetnotes. Backups include spare bungee, double ender, zipties, and a 2nd cutting device. This set-up is very streamlined, using 2 attachment points with double enders.

The small D-rings can be used as additional holds for spools or reels. I found these triglides with small D-rings very convenient as a temporary hand. Others use the DAPs to attach a canister light.

A butt mounted D-ring is available for additional space or longer term storage. Primary and exploration reels are best stored on this D-ring.

Personally, I chose to keep my contents in thigh pockets. This kept my backmount and sidemount configurations even more similar. However, there was a benefit to using the pouch, as it can be detached and brought in front of the diver. Then an item can be extracted and the pouch returned to the back position.

With thigh pockets, extracting items is by feel only. In addition, Steve notes that thigh pocket access becomes more difficult when carrying multiple stages. My short arms don’t help, but this is something I’ve worked on in BM configuration.

The Crotch strap serves multiple purposes. A smaller canister light is butt mounted on the crotch strap, and a larger canister via the DAPs. With the crotch strap on top of the canister, the canister is more securely held in place. The crotch strap also contains a scooter ring – for tow behind scooters. Lastly, the crotch strap keeps the harness snug and can provide a tie point for the BAT wings.


To reduce any chance of entanglement or line traps, tanks are streamlined. The only connection point is a small bolt snap attached to a line, held in place by a hose clamp. The line is as short as possible, only exposing enough to be able to cut in case of bolt snap failure.

The left tank has one hose retainer. When not in use, the regulator is tucked into the retainer. The retainer also serves as a back-up attachment point, in case of bolt snap failure.

The right tank has two hose retainers in the Basic configuration. The 7′ hose is tucked into the retainers, and they also serve as back-up attachment points.

Backplate and Pack

In order to carry necessary scuba diving gear as a carry-on (as well as save a little weight from luggage), Jeanna and Brian of Frogkick Diving made a backpack for their backplate.

For the technical scuba diver, a backplate and pack makes a lot of sense. I saw Jeanna’s design while at the UTD Symposium 1.0.

Backplate and pack front

Backplate and pack back

After seeing Jeanna’s and Brian’s design the prior year, fellow UTD instructor James Mott made his own version – with support for fins.

backplate and pack - with fins

Even though I joked about it to my wife and Dennis Weeks a few years ago while traveling in Mexico, I never took action. Seeing Jeanna’s design got me off my butt and I made the following from a computer bag. I loose style points, but gain laptop portability.

backplate and pack - computer bag

Staying hydrated – Technical Dive Ninja SIGG

Okay, this is a total self promotional blog.

As scuba divers, we know that hydration is incredibly important before and during the dive day.

Lately, I’ve been bad to the environment by buying bulk packs of water from Costco. Going through 3-4 bottles a dive day is definitely not ecologically sound (or financially smart).

The alternative was to bring either a Nalgene or SIGG reusable water bottle. Dissatisfied with available designs, I made my own – “It’s Okay, I’m Ninja” with a technical diving ninja (doubles, canister light, and Jet Fins).

It's okay, I'm Ninja - technical diving SIGG

I made it available via CafePress, but it’s a little pricey. If there’s real interest, I can consider an alternative source for my It’s Okay, I’m Ninja – technical scuba diving SIGG.

Sidemount helmet

Sidemount diving seems like the last refuge of individualized gear. Whereas back mount cave divers have more or less adopted the hogarthian configuration, side mount set-ups are quite varied.

Even the newly off the shelf units such as the Golem Gear Armadillo and Dive Rite Nomad are constantly being modified or “improved” by their owners.

The first thing that most sidemount divers tackle is making a helmet. The base helmet is either a kayak helmet, prostate climbing helmet, artificial construction helmet, or skateboard helmet.

I chose a kayak helmet since they are designed for in water usage and I thought that the foam liner would be more secure than the suspension liner of other helmet styles. And if I didn’t like the foam, I could rip it out.

With price being a major consideration and preexisting holes being another, I selected the Pro-Tec Ace helmet. At $40 and free shipping, it wasn’t going to break the bank.

For my head size, I chose a Medium helmet. After the modifications and with the use of a hood, a Small would have been a better purchase.

sidemount diving helmet - dac

First step was to drill four holes on each side to mount the back-up lights (BUL). Since BULs mounted on the harness is not optimal (they are blocked and interfere with the side mount tanks), the helmet use have two BULs attached. Steve Bogaerts recommends mounting then so that there is no glare and the focus is 10 feet away.

After securing the BULs, the next step is creating a mount for the canister light head. This is accomplished by cutting the appropriate sized PVC tube or coupler and then drilling 4 more holes into the left side of the helmet. Placement is immediately above a BUL.

Once complete and tested on dry land, it was time to hit the water. Immediately, the helmet was too buoyant. The closed cell foam designed to protect against impact made me head light. To a surprising degree too. While this may be a nice feature for paddlers, it is obviously not good for divers.

To resolve this, I removed all the side and back foam. I kept the top foam to provide a place for my head to fit. Plus, this would insure that the height of the helmet was correct. Removing the top foam piece would have caused the helmet to ride too low.

With the foam removed, the helmet is neutral in fresh water with my UK SL4 BULs.

sidemount diving helmet - smb

How to mark a stage or deco bottle

Brian of Frog Kick Diving in the Pacific Northwest has a good article on how to mark a stage and deco bottle. In addition to the how, he also explains the whys, which is equally important for the thinking diver.

For all countries, O2 bottles are to marked with “OXYGEN,” in English. This is to avoid any confusion when diving mixed nationality teams.

For those diving Metric, standard practice is to mark the depth with an “M.”

How to rig a stage or deco bottle

Andrew recently put together a video blog on how to rig a stage or deco bottle. This is useful viewing for anyone getting ready for technical diving and setting up their own stage or deco bottles.

Find more videos like this on Unified Team Diving

Here is a another very good reference for making your own stage bottle rigging. The bottom knot is a little more fancy, but both solutions are acceptable.

DIR Equipment Configuration: Light Head

While Internet forums are filled with discussions on DIR/UTD equipment configuration, I typically ignore most of the banter. Often times, these threads end up as nit picks on fine details, but miss the overall goal and value of DIR. However, the best discussions are typically improvements or recommendations that enhance the way we dive.

Based on recent discussions, we updated our light head configuration with a double-ender and bungee overtop. This equipment configuration now successfully serves multiple purposes.

  1. Light can be clipped with head up on the D-ring
  2. Light can be clipped with head down on the D-ring
  3. Bungee provides convenient thumb loop
  4. Bungee allows for temporary holds of cookies/arrows
  5. Prevents Salvo lighthead from accidentally on unsnapping from the handle*

DIR Equipement Configuration: Light head

There’s a recent video on the UTD site about this DIR goodman handle light head configuration.

Equipment needed:

  1. Stainless steel double-ender
  2. 1/4″ bungee
  3. Cave line
  4. O-ring

*Personally, I think that if the Salvo clamp on the handle was a little bit longer, more of “C” shape instead of a “U” shape, it might make the accidental unsnapping a non-issue.