Posted by mike on August 21, 2001 at 21:22:36:
In Reply to: Since no one has given you a good answer yet.... posted by Randy Medaris on August 21, 2001 at 18:21:32:
DIR (which is an acronym for "doing it right") is often associated with a particular gear configuration, but it is also a sort of philosophy or mind set that seeks to keep things simple, reliable, safe (as humanly possible) and most especially, to solve problems before they arise.
In the DIR config (AKA, Hogarthian configuration, after a Florida cave-diver named William Hogarth Mee) the BC would consist of a 316 stainless steel (ss) backplate (which looks like a torture device, but which in fact, is quite comfortable to most who try it). The ss backplate weighs in the neighborhood of 6 pounds or roughly 3 kg. that 6 lbs can come directly off your weightbelt. There are also aluminum backplates (2 lbs or 1 kg) and ABS (a type of plastic) backplates (1 lb or 0.5 kg) for warmer water locales.
The backplate harness consists of a single piece of 2 inch webbing with three stainless steel D-rings: one in front of, and below each shoulder and one on the left hip, towards the back. There is only one belt buckle, which should be made of the virtually unbreakable stainless steel.
A crotch strap will run from the base of the backplate, through one's crotch, and then terminate in a loop, which goes around the belt, just to the left of the buckle. This makes the whole rig rock-solid. It stays on your back, doesn't wobble or slide and practically feels like it's a part of you. The knife should be a small little thing that holsters onto the left side of the belt portion of your harness. The crotch strap may also contain a D-ring on the front (for attaching to a scooter or DPV or dive propulsion vehicle) and a D-ring on the back, where some cavers like to attach extra reels (not my cup o' tea just yet... not many big caves in the Peoples' Republik of California).
The whole rig should be sized such that you can easily slip out of the thing by shrugging your shoulders, leaning forward and wriggling a little, when you're back on the boat or shoreline
The ss backplate ahould have a number of holes and slots for the webbing. An air bladder (known as a wing) is attached to the back of the backplate via two screws. The wings come in many different flavors, depending on whether one is just doing warm-water diving with single tanks or whether one is wearing twin steel 104s on the back for a trip down into some cave or wreck or deep pinnacle. There are small, streamlined wings with 18 lbs of lift, and big whopping ones with 65 lbs of lift. AVOID WINGS WITH ELASTIC RETAINING DEVICES such as bungee (aka bondage) wings. The bungees create drag in the water and may interfere with oral inflation should the bladder get torn or punctured and things not be adjusted properly.
A single tank or a set of double tanks will then attach to the backplate and wings via those same two aforementioned screws.
OK, thats it for the BC! nice and simple and robust. best thing about it is that should you decide to take up tek diving, you can still use the same backplate and harness...just buy a new set of wings for $382.00 max, rent a set of doubles and you're ready to go! No $700.00 BC required : )
Regs, now thats a different story! I will let others on the board fill you in on the regs of choice, but generally, the Scubapro MK20 G250 or similar product is preferred, with a lower performance reg being preferred for the octo. Regardless of the choice of regs, the primary 2nd stage (your high-performance adjustable baby) is attached to a 5 foot or 7 foot long hose (the term "long hose" may refer to the primary second stage and the hose to which it is attached). The hose travels down the right side of your body from your first stage, across your waist or stomach, up the left side of your trunk (behind your left arm & shoulder) over the back of your neck, and around to your mouth, where it does its work. The octopus is attached to a relatively short hose that simply goes around one side of your neck. The octopus is held in place by a simple band of elastic cord (bungee) tied to the mouthpiece (but not in such a way as it would interfere with breathing). The rest of the elastic cord goes around your neck like a necklace. WOOPS! its late here on the west coast and i forgot to mention, when gearing up, put your octopus in place around your neck first, THEN place your long hose reg.
The rationale behind this seemingly counterintuitive regulator arrangement is as follows: In an out of air emergency (OOA), a panicked diver is most likely to grab the first reg that he/she sees, which is the one in your mouth. The additional benefit lies in the knowledge that this regulator is fully functional, because you've just been breathing it the whole time. OK, so now some freaked-out diver swimming at death's door has just ripped YOUR reg out of YOUR mouth, and is sucking on it wide-eyed for dear life. What are you supposed to do? Very simple, just look down, and grab your octopus (which you wear like a big pendant around your neck) and grab it, preferably with your mouth...no hands if necessary! Give 'er a good purge and start breathin! What about the panicked OOA diver that is inhaling your remaining air supply at warp-speed? Well, duck your head, let that long hose unfurl from behind your neck, out of your waist band/belt/harness/cannister light/weight pouch (more about all this in a second!) and the panicked, wild-eyed OOA diver will then fall away to relatively safe 5 to 7 foot distance from you (at least they won't be thrashing around in your face).
Lets get back to the rig: on your right chest D-ring, you can clip a small backup light (Halcyon Scout light...but i currently have a UK mini Q-40 which was all i could afford) which will then be held to the strap by a small loop of bungee material. Through your left chest D-ring, you will pass your BC (wing, really) LP inflator hose (which by the way, will be attached to the left side of your primary reg). You may also attach another backup light here if need be (i personally don't like anything there, but then, i'm not penetrating wrecks or caves yet either). There will be another elastic ring around your left chest strap, which will hold your corrugated BC hose(and it's low-pressure hose to your reg) in place. Your corrugated BC inflator hose should not be so long that it bunches up. It should be just long enough for you to vent ALL the air in an upright position. This way, you can still vent your air if you find yourself ascending a little too fast for comfort, and at the same time, not have the inflator valve dragging on and scarring 700 year old coral formations. Speaking of gauges and consoles that drag and tear up the Acropora, the SPG (brass Scubapro: cheap plastic ones need not apply) should be clipped to the left (and only) hip D-ring.
OK, thats it for the basic BC/reg kit. Most DIR folk use the Halcyon ACB integrated weight system, with perhaps, the addition of more weight behind the backplate if needed. Most will also have a rather expensive cannister light worn on the right side of the belt portion of their harness. That aforementioned 5 to 7 foot long hose can either have a small loop tucked into the right side of the belt, or it can go snug between the cannister light and the outside of your right leg.
There are many more issues with regards to DIR, including the use of computers, mounting of compasses, gauges, etc and combining dry suits with steel tanks versus aluminum tanks with wetsuits, single tank with Y-valve or H-valve, or doubles with isolation manifold /w/ rubber tank knobs, choosing the right gas mixture for the dive (what percentage EANx, what percentage trimix...etc), the carrying of stage bottles, SUICIDE CLIPS versus piston-bolt snaps, break-away o-ring ties, NO metal to metal connections, opinions of redundant air sources (some don't like pony bottles) choice of fins (Scubapro Jetfins /w/ spring straps) type of lift-bags to be used (closed circuit only) and where to store 'em when you're not using them (behind your back) Also, NO SOLO DIVING! (can't say as i practice what i'm preachin' here:-)
and others.
DIR is more than just backplate, wings and long hoses. As a mind-set or way of approaching things (much of it basic common sense really), it seeks to minimize risk to the diver when the fit hits the shan, minimize damage to the environment (no dangling gauges, buoyancy and trim are IMPORTANT!!!) Maintain neutral bouyancy (don't land on the bottom, break off chunks of coral older than your grandmother, or stir up clouds of silt). Maintain your compass (left hand) and depth gauge & bottom timer or computer (right hand) on your wrists where you can see them on a split-seconds basis. Have redundant lift in the form of a drysuit or at the very least Al tanks, which will be positively buoyant when empty (heaven forbid should things ever lead to that, but if they do, at least you'll have additional lift). Your buddy is your source of redundant equipment and air, so choose your buddy wisely and don't dive with "strokes" (the term "stroke" is insulting, and refers to among other things, a person who has an unsafe attitude towards diving..like that fellow on this board who was inquiring about diving under the influence of marijuana) Harden yourself psychologically against mishap (practice your contingency plans should your mask come off in COOOOLD water, know how to use a compass and use it! practice OOA drills)
for additional info, check out http://www.gue.com, and be advised that while much of the DIR stuff was developed by people who like to dive to 300 feet in dark scary caves for six hours at a time, the mindset and basic configuration also apply quite nicely to shallow recreational diving, both here in California where we have these magnificent kelp forests, and as i found out recently, over shallow coral reefs in tropical waters.
hope this little primer helps.