Nekton

Breathing and donating the long hose is something I was taught by my OW Instructor (NAUI) and this has always seemed to me to be the most obvious and logical response to an OOA scenario. The diver in most immediate need quickly receives a known working regulator. I can donate my primary reg and retrieve my backup almost instantly, (no delay while you go through some sort of elaborate dance to find an "occy" and unclip or remove it from a pocket).

The movie below is at "demonstration speed" I can deploy the reg faster than shown.

Because I am asked a lot of questions about my equipment this series of discussions is, hopefully, intended to go some way towards answering them. Remember though, I'm still only learning about this stuff myself. (I've only taken the most basic level GUE course to date). Don't take my opinions as gospel, seek information from a range of sources and use your own common sense - or save yourself the angst, contact GUE and do a course! (In some sections, I have also included links to web resources that I have found useful.).

Regulators/hose layout
In DIR diving, the diver donates the regulator in their mouth to the out of air diver and retrieves a backup that is kept in place by a piece of bungie cord around the neck. This approach to air sharing is a central tenet of DIR. The placement and routing of hoses is important, as

By donating the regulator in your mouth, the OOA diver immediately receives a known working regulator. Because the backup regulator under my chin is MY regulator in the event that I need to donate my primary, I check that it works properly on every dive. (How often are occy's checked? What guarantee they won't fall out of a retainer and drag in the sand or get hooked up somewhere hard to reach? I've tried just about every type of retainer on the market, none are fool proof) In an OOA emergency the OOA diver is likely to take the regulator out of your mouth, so it pays to be ready for this. DIR divers practice "modified S-drills' on every dive and full air sharing drills regularly.

A balanced piston or diaphragm first stage is preferable to an unbalanced first stage, particularly if you plan to do more challenging diving later on. Non-swivel first stages, such as the Apeks US4, DS4 or TX100 - I'm not familiar with the ATX range - or Oceanic equivalent are preferable. I use Apeks US4 or DS4 first stages. Swivel first stages introduce an additional failure point, (the swivel O-ring) and I also find they make reaching the tank valve much more difficult, even for a buddy, as the regulator hoses bunch up against the valve. Being able to reach your tank valve/s while fully kitted up is an important self-aid skill to master. I don't see the advantage of swivel first stages as the inflator hose usually prevents the swivel from moving in single tank diving, thus negating any supposed benefit.

A seven-foot hose provides ample space to share air without swivels. The only possible exceptions are the Scubapro, Atomic and, possibly, the AirDive swivel first stages that have a port in the top of the regulator, facilitating
neater hose routing with a single first stage (see below).
I have had better service out of my diaphragm regulators,
however, than my older piston regulators, so wouldn't go back
to this style of regulator.

There is some debate over the use of dual-outlet (H and Y) valves. I'm undecided, but certainly agree that dual outlet valves do not circumvent the need for twin tanks and an isolation manifold in overhead environments, including deco diving. Nor do they circumvent proper buddy or team diving skills. However, I do feel that using a dual outlet valve makes hose routing a lot cleaner compared to a single first stage (see below). There is also redundancy between wing and dry suit inflators and primary and backup regulators. Meaning that in the event of a first stage, hose or o-ring failure, air supply and buoyancy control can be maintained. This is an aspect of my gear that a lot of people focus on but it's really of little relevance.

Second stages should be simple to service and maintain in the field without requiring special tools. If the diaphragm cover can be easily removed sand and grit or other obstructions that might interfere with the function of a regulator, (causing leakage or affecting the water proof integrity of the rear valve) can be dealt with, even underwater. I prefer regulators with proper exhaust ports, ensuring that bubbles are directed away from the divers face, unlike many compact regulator designs now popular. The primary regulator should be air balanced for comfort and performance, while the backup regulator should be unbalanced or have diver adjusted cracking pressure (adjusted down) to prevent leakage and free flow. Again, my regulator of choice is the Apex T or TX series (T20, TX40 and TX50). I have also heard good things about Oceanic and Atomic and I have some Scubapro regulators that still work OK.

Hose length is important. While a 38 or 40-inch primary hose can be used, (I dived with one for 6-8 years) there is no way that I would now go back to one. The shorter hose usually ends up sticking out at the side and becomes an entanglement hazard. Some divers use shorter hoses with elbow joints so that they can be routed under the arm, but this introduces an additional failure point. The longer hose, ideally 7-foot, on the primary is brilliant in that it offers plenty of room to swim beside an OOA diver away from trouble, or control a panicked diver. Everyone who has seen me in action with a long hose has appreciated the benefits. The longer hose can also be more neatly routed without the need for elbow joints or other modifications. A 7-foot hose is essential for any overhead diving in that it facilitates a single file exit from a restriction. Routing the hose under a canister light is preferable, but running the hose under the knife works fine when there isn't a canister.

Correct hose routing is important. Correct hose placement facilitates a rapid response to a problem. Keeping everything close to your body not only helps prevent entanglement, but, in combination with the tape harness and wing, provides a clean, low drag setup. Excess hose length introduces clutter and potential entanglements, so I buy custom length hoses. I currently use a 7-foot (80inch) primary hose, 24-inch backup regulator hose and 24-inch SPG hose. My wing inflator came from Halcyon - it's either 22 or 24-inch - and the dry suit inflator (if used) is 28 inch.

Gauges and attachments
I use stainless steel bolt snaps (bought from a local chandlery) ONLY for attaching hoses or accessories. These are the only reliable option. So called "suicide clips" or gate clips are an accident waiting to happen and have no place in diving. Likewise, those fancy plastic clips with quick release buckles or retracting cords. Plastic clips will break at the worst time, and anything that looks complicated or relies on some sort of mechanism to retract cord will inevitably jam up. The ocean is not the place for unnecessarily complicated solutions. Keep it simple and reliable.

Even when using high quality stainless steel bolt snaps it is possible to have a clip lock shut. It's important that any gear can be quickly pulled - or cut - loose if necessary. Never have metal-to-metal attachments.

My primary regulator and pressure gauge are attached using a breakaway tank O-ring. The idea being that a hard tug should break the O-ring. Obviously, it is critical to be able to get a regulator loose quickly if needed.

Nylon line, (cave line) is used for my strobe, torch and other accessories that can be cut loose if necessary. I have also used a loop of bungie cord, (tied with a double fishermans knot or a square knot) to attach some heavy items or other items on the fly, like spare weights on charter dives and tape measures.

Placement and attachment of gauges...

I have always tried to prevent my equipment from dangling down below me. Dangling gauges can catch on reef or wrecks, damaging both the equipment as well as benthic organisms. (I used to use a gauge cage, but these simply make matters worse). Gauges can also get "lost" if they become caught up on your gear. One solution is to attach your console to your harness, but with the long hoses needed to effectively use gauge mounted compasses, the boot - that obscures hose damage or loose fittings - and the weight, this is really a sub-optimal solution. In addition: depth is a critical parameter. If the depth gauge is on a console stowed in a pocket; clipped to a BC; or hanging down below the diver from a hose, it cannot be effectively monitored. The diver becomes overly dependent on visual references such as the reef or wreck, an anchor line or their buddy.

The best solution is to put your compass and depth gauge on your wrists and just use a simple analogue pressure gauge with a hose that is just long enough, (24-inches works for me) to allow you to read the gauge when unclipped. Some consider integrated pressure gauges on computers to be a good way of streamlining gauges, but I have seen and heard about lots of problems with integrated units. Relying on electronic devices for a critical parameter like gas supply is also, in my view, fundamentally flawed. On several occasions I have seen electronic contents gauges fail or give spurious readings. (And because I don't see many people using these devices it's not a good average!) I started using a separate contents gauge and wrist mounted depth gauge well before I heard of DIR. It's much more streamlined and functional than trying to put everything onto a console. Key dive information is right there in front of you all the time. Notice also that I don't have any boots or consoles around the pressure gauge. These hide damage to hoses and can even disguise the fact that a hose is working loose. On one occasion I saw a divers SPG come off completely (with obvious results) during a dive, because the thread had worked loose and the boot disguised the fact.

I attach my compass and depth gauge, (OK! Computer, but I use it in gauge mode as the only reliable computer is the one between your ears) to my wrist with a continuous loop of bungie cord tied with a double fishermans knot.

Bungie cord is cheaper, (less than $1 vs $40+ for a standard strap); safer, (much less likely to break than a rubber strap and if a pin breaks or falls out the computer stays on my wrist); quicker to don and doff and no mucking around with buckles; and presents less risk of entanglement than the buckles and other hardware on conventional straps. It also means that paranoid people like me can forget about using lanyards as a backup for unreliable wrist straps. Lanyards are a bad idea. They add to the clutter and create an entanglement risk. Set up your gear correctly and they aren't necessary.

Accessories in pockets...
Pockets should be on the exposure suit not on the BCD. Whoever decided that pockets belong on the front of a BCD clearly had no concept of drag or ergonomics. If placed correctly on the sides of the suit, pockets produce minimal drag and are much easier to access. Most people keep keys and wallets in their pant pockets on land, so the outer thigh is a natural, intuitive place for pockets to be placed. Being on the side of the body, pockets remain in the slip stream of the divers shoulders, minimising drag.

I don't carry a lot of accessories, so currently only have one pocket on my wetsuits and two on my drysuit. (I mostly just carry a spare key for my car, wetnotes, whistle, lift bag or surface marker buoy and spool). When diving dry, I carry the spool, scissors and safety sausage in the left (bellows) pocket and wetnotes, key and whistle in the right (non bellows). I think that this works out OK. As a general rule equipment that is used regularly should go in the right pocket and spare gear (eg. spare mask), used less frequently, in the left. All pockets have velcro closures. Zippers should never be used as sand can easily jam them in either the open or shut position. (Once again, I can't fathom why manufacturers put zippers on pockets? If you bother to carry something, it's presumably important enough that you want to be able to access it during a dive and not be prevented from doing so by a pocket that's jammed shut by sand?) The following site shows the type of pockets to use and what goes in each...

http://www.wkpp.org/articles/Gear/equip_moreimages_2.htm

You need to be able to cut accessories free if necessary, so bungie cord is better than any type of metal attachments in a pocket. I use small bungie loops close to the top of the pockets. I burnt the holes for the bungie loops with a soldering iron and then coated the edges of the holes inside and out with Aquaseal (to form a grommet). Obviously you can attach stuff to the loops with bolt snaps but for some items that I don't need to remove in general use I attach them to the bungie cord with an O-ring and cable tie or cave line.

Weighting and thermal protection

Most new divers, and many experienced divers, use a lot more weight than is really necessary. In addition, weight and buoyancy is often poorly distributed over the diver's body with virtually all of the weight usually contained in a weight belt positioned low down on the divers hips and all of the buoyancy up around the chest with the lungs and the BC. Sometimes weight is contained in a heavy steel tank that makes the diver unstable underwater and potentially overweights the diver, preventing a safe ascent to the surface if a problem occurs. Divers often fail to consider the implications of other equipment choices (such as tanks and lighting systems) on weighting. Choosing the right tanks and exposure suit, and distributing weight correctly, can significantly improve trim and comfort in the water.

There are two important principles to keep in mind when discussing weighting...
Firstly: Open water divers should strive to be neutrally buoyant at the end of a dive, (with low tank pressure (35 bar) and no air in the wing/BC or exposure suit) and be able to float comfortably during a safety stop without struggling to stay down. At the surface, with no air in the wing, a neutrally buoyant diver will float at eye level rising and sinking with each breath. Fins should be kept pointing downwards and at rest while testing for neutral buoyancy.

Secondly: For safety, divers should retain sufficient weight in a ditchable form so that if a wing/BC failure occurs at the start of a dive - when a diver is at their heaviest with full tank and compressed wetsuit (if used) at depth - they are still able to ascend and float comfortably on the surface. This is not quite so critical with drysuits as these provide redundant buoyancy, and both the wing and suit failing on a dive is unlikely (particularly if they are supplied from different first stages. Nevertheless, for safety, trim and to maintain a consistent equipment layout, I still consider the use of a weightbelt essential when using a drysuit.

When determining the appropriate weighting, divers need to consider the type of tank and exposure suit appropriate for the dive. Divers also need to consider how much extra weight must be added to their rig and how that weight should be distributed.

Prior to the development of BCD's, divers predominantly controlled their buoyancy with lung volume. (Experienced divers will be aware of the importance of breath control in controlling ones position in the water even with a BC). The right aluminium tank provides a shift in buoyancy from three pounds negative to three pounds positive, keeping the diver close to neutral throughout the dive and preventing over-
weighting at the start of the dive that could not be compensated for by the divers lungs or by swimming up with the fins.

Unfortunately, while BCD's have significantly improved diving safety and comfort they can instil a level of dependency. Divers will often carry more weight than they need, or perhaps a heavy steel tank or other heavy piece of equipment, and compensate by adding air to the BC. Unfortunately this approach has a number of problems. By adding more air than otherwise needed to the wing/BC, the diver significantly increases drag and swimming effort - and air consumption! Having a lot of air in the BC also results in rapid shifts in buoyancy as a larger gas volume expands or contracts, (often causing divers to believe that they need more weight when, in fact, they need less). Using a steel tank with a wetsuit or neoprene drysuit can leave a diver dangerously overweighted in the event of a BC failure.

In my view BCD's should be used sparingly. If you're using the right tank and are correctly weighted you should only need to put a small amount of air in the BC to compensate for the extra weight of gas you are carrying and the compression of the exposure suit, (if applicable). Aluminium tanks that remain close to neutral and offer a shift in buoyancy from three pounds negative to three pounds positive (like the SA80 made by Luxfer), are the best choice for openwater diving (single tank) and twin tank diving with a wetsuit.

Exposure suits

Choosing the right exposure suit requires a lot of thought. Things to consider include; the temperature range you will be diving in; the duration of the dives; your level of activity and other issues like comfort. Wetsuits are the main stay of the diving industry, but now that I own one I love my drysuit. I wouldn't go back to a two-piece 5mm suit, (although I do still use semi dry suits a fair bit - particularly for working in the dive shop and research diving, where the suit gets a lot of rough treatment and I'm very active). I feel that there is a critical point where adding additional layers, or thicknesses, of wetsuit becomes counter productive and the weight required to sink the suit together with the restriction of movement make wetsuits a poor choice.

Whatever the decision, however, the exposure suit must keep the diver comfortable for the duration of the dive and the trip back to shore. I don't care if people berate me for wearing a drysuit at times; if I stay warm, I can do more diving; I don't get as fatigued; and I stay healthy. It's my experience that getting cold during a day's diving often results in flu like symptoms on subsequent days, interfering with my comfort and productivity, or, when I'm travelling, my desire to do more diving. Getting cold can also increase your chances of DCS or injuries due to poor mental function or dexterity.

I've owned a number of wetsuits. At least four two piece 5mm suits, a few semi-dries and a number of surfing and warm water suits, along with a range of accessories. I've yet to come to any firm decisions on brands of wetsuit but I prefer properly fitting semi dry suits to two piece wetsuits for their comfort and flexibility in terms of the additional thermal layers that I can add under the suit.

As temperatures drop I now tend to add several thin, close fitting layers of neoprene under the suit, (focusing on the areas that lose most heat; the head and torso, upper arms and legs) rather than single thick layers. It's hard to quantify how successful this approach is, but I feel that it works. A zipper less under suit (1-2mm), thin arctic vest (2-3mm, 5mm for colder diving) and a 5-7mm semi dry over the top is about as much as I'd use. In the tropics, I sometimes use a 3mm shorty, with 1mm under-suit and "rashie". Again, the layers seem to work well in reducing water flow over the skin and therefore heat loss.

The optimum choice in drysuit diving is a trilaminate shell suit. Neoprene suits compress with depth, requiring divers to carry extra weight to compensate for the buoyancy of the suit at the surface. This results in a considerable change in buoyancy as the suit compresses, requiring the diver to add excess air to the BC to compensate. If correctly used the buoyancy of shell suits is constant throughout a dive.

Contrary to many training programs, the drysuit should never be used for buoyancy control, with only enough air added to prevent a squeeze. The wing is the primary buoyancy device. Teaching divers to use the suit for buoyancy results in greater dynamic instability during the dive, (as air migrates over a larger distance that it would in the wing); risks an uncontrolled feet up ascent; and will not work in more challenging diving like cave and technical diving, where the weight of equipment carried would require an excessive amount of gas to be added to the suit. Training should always reflect the real world application of skills. Teaching divers the wrong approach at the beginning requires them to relearn important skills later on, which is fraught with risks and a needless waste of their time and effort.

Shell suits are much more comfortable and allow the diver to vary the level of thermal protection for different diving conditions. The DUI TLS350 is the dry suit of choice for DIR divers. A "cave cut" suit is best, (for closer fit), with the older style, high profile Apeks shoulder dump valve and older style self donning zipper. The suit should have a standard DUI velcro pocket on the right hip and a bellows pocket on the left. I have a shoulder entry version of this suit which is not such a close fit. The extra expense for the cave cut TLS350 is worth it. (I'll get one eventually). I have added CF200 (crushed neoprene) boots to my suit. These boots are more comfortable than rigid rubber boots; allow you to use the same size fins used for wetsuit diving, and minimise air trapping in the boots. I'm not sure what DIR divers commonly use, except that Rock Boots are frowned upon. A P-valve and catheter are essential for comfort and to allow the diver to remain adequately hydrated throughout the dive. Dehydration increases the risk of DCS and dehydrating yourself to avoid the discomfort - or flooding your suit from the inside - is a very bad idea. A balanced P
valve, (like the one made by Halcyon) is best. It should have a balance chamber and one way valves to prevent the suit flooding if the catheter breaks and to help prevent bladder infections).

The best place for pockets is on exposure suits. By putting pockets on the outer thigh, accessories can be easily and comfortably reached and the pockets remain in the slip stream of the shoulders, minimising drag. DUI pockets can be retro fitted to wetsuits or drysuits if need be. Choose pockets with velcro closures ONLY, zippers can jam. I am constantly amazed at manufacturers who put zippers on pockets. If an item is important enough to carry you need to be able to get at it immediately. Zipper pockets can easily jam shut with sand rendering any items in the pocket inaccessible. The correct DIR pocket layout is standard velcro pocket (CLF200) on the right hip and bellows velcro pocket on the left.

Trilaminate drysuit thermals (DUI 200 and 400 gram jump suits) are the optimum choice for drysuit divers. These are made with boot thinsulate (B series). This material maintains it's loft better under pressure, (requiring less air in the suit) and works effectively with argon for long exposures in technical and cave diving. Even when a suit is flooded, this combination can keep the diver warmer. Quality thermals are essential with a membrane suit and the extra expense is worth it.

Divers should endeavour to add a minimum amount of gas to the suit during the dive and dive the suit "shrink wrapped". I don't usually start adding air to my suit until I reach 8-9 metres and then only enough to avoid squeeze. By reducing the amount of air in the suit divers prevent the dynamic instability that results from a large air bubble moving around the suit. I can easily invert myself without any problem, (my boots don't fill up with air).

As I don't require a lot of weight when diving either wet or dry, I mostly use an aluminium backplate, rather than the more popular and heavier stainless steel, so that I can retain a good proportion of my weight in a ditchable form (weight belt or light canister). Backplates can be bought in a range of weight configurations - although 3 pound aluminium and 6 pound stainless plates are most common - and additional weight added, if required, in the channel of the plate, (again without creating additional drag).

The amount of ditchable weight required depends on the exposure suit used and the weight requirements of the individual. I use around 6-9 pounds with a 5-7mm semi dry; about the same with my drysuit and thin thinsulate (9-12 pounds with 400 gram thinsulate). This is something that can only be determined on an individual basis. Ditchable weight is best distributed between a weight belt and canister light.

Divers should be aware of the weight characteristics of other items of gear used. A canister light for example can be up to three pounds or more negatively buoyant and can allow further weight to be removed from the weight belt. In fresh water a canister light is all the weight that I need with a drysuit, light thermals, aluminium backplate and aluminium tank. Canister lights can   be considered part   of your ditchable weight if properly configured, (on the waist belt of a harness).

Some commercial BCD systems have integrated weight pockets on the back, front or sides. These not only add complexity to the whole set up, but also increase the profile for drag. I also believe that most are ill conceived. All divers are trained how to ditch a weight belt during training. Therefore, everyone should know how to ditch a weight   belt. Most integrated systems   on   the   market   use   different   release mechanisms. Some are barely recognisable as weight systems. While familiarising one's self with a buddies gear prior to a dive is essential, it may well be that a divers buddy is not the one called upon to perform a rescue. Also, should a diver be called upon to remove their kit underwater during a dive, an integrated system would leave a diver greatly under-weighted, (and their kit overweighted); a dangerous position to be in.

The weight system should be retained on the diver. For these reasons, (and the fact that I hate lifting integrated BCD's onto dive boats) I do not recommend the use of integrated weight systems. Weight belts are also considerably cheaper and easier to replace, (unless you   insist on paying more for one by choosing some sort of convoluted design with weight pockets or the like).

With a metal backplate (aluminium or stainless steel), the right wing, the correct amount of weight on a weight belt and the right exposure suit you get excellent balance in the water; you swim horizontally rather than feet down/head up, like a conventional SCUBA setup where all the weight is in a belt around your waist and all the buoyancy in the BC, (usually up round your chest). Horizontal trim is very important in minimising fin damage and silting and for improving efficiency. A horizontal diver presents less surface area for drag and will move through the water much easier.

Find out more �

In Part 4, of this series, Simon talks about stability, trim, finning techniques and accessories, but to find out more about DIR diving and its underlying philosophy, he recommends the following web pages as a good starting point:

What is Doing It Right Diving? by Jarrod Jablonski
Beyond Hogarthian...Doing it Right by Dan Volker
Doing It Right Gear Configuration by George Irvine
Halcyon FAQ page
Transcript of George Irvine's lecture to BAUE
Online video streaming of DIR 1 and 3 video's by George Irvine (note you may need to install Windows Media Player on your computer and use Internet Explorer (DIR 3 is aimed at recreational divers))
NEW DIR books (Fundamentals of Better Diving, Tech 1 and Cave 1 manuals) by Jarrod Jablonski (available for online purchase)

Simon Hartley is an Associate Lecturer in the School of Environmental Science and Management; teaching computing, statistics, geographic information systems (GIS) and remote sensing and undertaking undergraduate and postgraduate supervision. He is currently undertaking a Masters by research examining the marine benthic communities of Julian Rocks (Byron Bay). His research interests include marine science and GIS. Simon is an experienced scientific diver with over 13 years diving experience. He has been involved as a research diver or team leader on many staff, undergraduate and postgraduate projects in the School including; several coral community studies from the Solitary Islands to the southern Barrier

Reef, work on shallow water Rhodoliths in Moreton Bay, underwater heritage studies in Byron Bay, work as a team leader for a Marine Archaeology field school in South Australia, turtle tagging and monitoring studies, surveys of wobbegong and grey nurse sharks off Byron Bay and ongoing work on the effects of trawling in Moreton Bay. Simon has a diverse range of diving skills and interests including; underwater photography (still and video), general marine survey techniques, use of light tools and lift devices and maritime archaeology. As the President of the North Coast Chapter of the Australian Marine Sciences Association, Simon is involved with promoting postgraduate and undergraduate marine research on the North Coast of New South Wales. Simon has worked part time in the recreational dive industry for six or seven years and has also been active in a number university and private dive clubs over the years, including being on the executive of the Southern Cross University dive club for five or six years. He has taken part in a number of community based projects, including population studies of the grey nurse shark and the development of the code of conduct for recreational diving with sharks, and fosters links between the dive industry and university. He can be contacted at: shartley@scu.edu.au or visit his website at: http://www.scu.edu.au/schools/esm/staff/pages/shartley/projects/gear/