Category — Configuration

Un an après avoir terminer mon cours de Full Cave Diver chez Protec, je décide d’approfondir mes connaissances de plongée en grotte. Après de nombreuses discussions avec Patrick nous arrivons à la conclusion que la prochaine étape pour moi est le cour Basic Sidemount. Ce seront donc trois jours intensifs de plongée, une  nouvelle configuration de mon équipement et je l’espère, de nombreuses nouvelles sensations. 
Lors de mon inscription à Protect, Patrick me fait comprendre  que la première phase est tout d’abord l’élaboration  de mon harnais pour plonger Sidemount. La solution la plus facile est d’acheter un harnais type Transpac, ou similaire. Nous optons pour une seconde option, celle de le fabriquer nous même. La veille du cours je me procure donc du webbing que l’on découpe à mes dimensions, et bien sûr ma vieille stab.

Premier jour, il est 9 heures de matin et je suis à Protec. On commence par un peu de théorie. Patrick m’explique les différents aspects de la plongée en Sidemount avec ses avantages et ses inconvénients, ainsi que la différente configuration du détendeur. La plongée en Sidemount consiste à avoir ses bouteilles sur les côtés. Le but est de me permettre dans le futur de plonger dans des grottes plus étroites, ce qui m’est pour le moment impossible avec mes doubles bouteilles sur le dos….

Je passe donc toute la matinée  à la fabrication de mon harnais. Après deux heures de travail le résultat n’est pas trop mal ; il y a encore quelques réglages à faire, mais ils se feront après les essais en piscine. Pendant ce temps Patrick s’est occupé de ma stab. Toutes les poches et tous les clips ont été retirés. Petite pose déjeuner, et me voilà dans ma combinaison, mon harnais avec ma stab sur le dos.

Mise à l’eau dans la piscine de l’hôtel Mom’s ; j’attache mes bouteilles de chaque côté et je descends, le temps de faire différents tests de flottabilité. En sortant de l’eau on discute des changements et ajustements que je dois effectuer sur mon nouvel équipement. On va dire que ce sont mes devoirs pour le lendemain.

Deuxième jour, on se donne rendez-vous au magasin pour un dernier ajustement de l’équipement, avant de partir plonger dans les cénotes  Chikinha et Xtabay. Sur place avant de se mettre à l’eau nous revoyons les basics de la plongée en grotte Backmount (signes, position et touch contact), puis les nouveautés du Sidemount (touch and go). Une fois dans l’eau je réalise différents exercices de flottabilité (nager sur le côté et sur le dos), ainsi que retirer les tanks sous l’eau et de les replacer (position du superman). Avant notre première plongée en grotte nous avons effectué plusieurs exercices de touch and go dans la zone de caverne.

Bulble check et gear matching réalisé, nous sommes prêts à plonger. Je suis le guide, lorsque je déploie ma ligne d’ariane, je m’aperçois qu’il y en a déjà une en place, je reste donc à sa droite et la suis jusqu’au moment ou l’on rejoint la ligne principale de la grotte. La plongée dure une heure, et la vers la fin nous faisons quelques exercices en zéro visibilité. Ce fut une très belle plongée. En sortant de l’eau, debriefing de rigueur afin de voir quelles sont les modifications à faire pour améliorer ma flottabilité. Au même moment  sortent d’autres plongeurs, l’un deux est Bill Philips ; petite discussion avant de repartir vers Protec et de terminer cette belle journée.

Troisième et dernier jour ….L, on se dirige vers Chack Mol, pour faire deux plongées. Comme la veille, petit réajustement de l’équipement. Le but  aujourd’hui est de faire deux plongées dans des espaces beaucoup plus réduits ou je pourrais voir l’efficacité de ma nouvelle configuration.

Tous s’est bien passé durant ces trois jours, mais je me rends compte qu’il me faudra  de nombreuses plongées afin de pouvoir véritablement maitriser cette nouvelle configuration  et pousser son utilité au maximum.

Je suis vraiment impatient  de retourner dans l’eau lors de mon prochain temps libre pour améliorer ma technique en Sidemount et surtout de continuer ma formation technique en grotte.

When diving into caves, wrecks or under ice divers are introduced to a number of hazards not associated with open water diving. Some of these are easily managed. Others may be life threatening. General hazards include total darkness, loss of visibility, increased potential for confusion, unexpected currents, cave ins, restrictions, depths, unknown distances, mazes, turbidity / silting, current, sharp surfaces and projections, collapse, debris slides, restrictions minor and major, depth, distance, time.

Darkness

Absolutely no light penetrates most cave systems and one of the first things to realize is that the darkness is total. Not the slightest bit of light penetrates the solid rock ceiling, there are no stars and there is no moon. In caves the prospect of being lost in the dark can have chilling effects. When lost or when loosing ones light stress levels typically climb. Don’t let panic skyrocket. Cave diving requires disciplined self control to function correctly. This discipline must be learned and practiced.

Being Lost

Several common factors, or combinations of factors, contribute to the possibility of a cave diver becoming lost. Becoming lost is a threat on any cave dive. Caves frequently present divers with a number of mazes, dead ends and multiple levels of formation. Accidentally wandering into an unintended passageway can result in dive partners becoming lost. In fact, one of the leading causes of cave fatalities is the failure to follow a continuous guide line and set jump lines that lead all the way back to the surface. Guide lines are the diver’s path back to the entrance, they are a cave divers life line. Guide lines offer life insurance by providing cave divers with a marked path to the surface. It is imperative to keep an eye on these lines at all times. When visibility is good you should swim close to the line at all times so the line can be easily located. It is important not to stray too close to the line neither since the possibility of becoming entangled in it increases. Entanglements can become killers because they can result in broken or loosened lines. When limited visibility conditions occur, one must stay closer to the line. The best technique to stay in touch with the line once visibility has deteriorated is to swim with your thumb and forefinger forming a ring and looped over the line.

Visibility

In explored caves it is common to find permanent lines with arrows pointing toward the nearest route to the surface. Turbidity is caused by stirring up debris on the cave floor due to poor swimming techniques or due to percolation when exhaust bubbles hit the ceiling. It can reduce visibility to zero within seconds. From both a dive safety standpoint and an environmental point of view with cave conservation in mind, it is important for you not to stir up the bottom of a cave. Tannic acid is the color of soil and can be washed into the water by rivers or rain. It has the color of tea or coffee with the same visibility characteristics. A Halocline is the interface of fresh and salt water and when mixed produces zero visibility.

Water Flow

Current in caves can range from none to mild and even to severe. New cave divers are often intimidated by these currents. They tend to overwork and become tired quickly. By carefully employing proven techniques, the work may be reduced to a less demanding level. The best way to beat the current comes with learning to read the cave. Areas where the surface is smooth have been polished by the flowing water. So, you should look for jagged and pitted surfaces. They exist where the current is weakest. Current can also be out flowing or in flowing. Sometimes caves divers may encounter passageways featuring flows differing in direction from the passage currently being explored.

Cave or Wreck Collapse

Cave-ins ( collapses ) are rarely encountered in cave diving. Water pressure acts as a support and stabilizes submerged tunnels. It is only when water levels drop that the possibility of collapse exists. Occasionally, in some caves a small portion of the cave structure will fall in.

Debris

During floods, debris builds up in the down slopes of cave openings and in the runs. When the water table drops, additional debris is blown out of various passageways and is deposited on the cave floor. As these strictures extend toward the surface, more debris builds up in the run. At some point, the volume of these deposits reaches a point where gravity causes it to slide back into the cave. The result, in both cases, is an instantaneous loss of visibility. In fact, on one of these occasions visibility can be so obscured that it would proof impossible to get out if divers hadn’t had the mandatory foresight to install guide lines beginning at the cave opening. In some situations, it is possible that the cave opening actually becomes blocked.

Restrictions

Restrictions are choke points where access is reduced. They can be either minor or major. A minor restriction is a slight narrowing which, although restricted, still allows two divers to pass through it not side by side or on top of each other but in a single file following one another. A major restriction, on the other hand, only allows one diver to pass if the equipment is to be taken off and pushed through the restriction. As a rule of thumb the equipment is never taken off due to potential problems with buoyancy, damage, entanglement and cave conservation. If the need arises to pass through a mayor restriction gear configuration such as sidemount or no-mount have to be implemented. Obviously, the risk associated with a major restriction involves becoming stuck. When entering restricted areas be careful to evaluate the best passage route while also concentrating on relaxed breathing. If stuck, exhale some air and slowly maneuver your body and simply dislodge your self. Do not try to “ power through ” restrictions. You may become severely wedged. We can’t stress it hard enough. Take it very easy when swimming in tight spots. It is very easy to tear a BC bladder or damage your gear. Again, learn to read the cave and avoid abrasive and protruding surfaces.

Depth

Depth in caves can be very deceptive because you have a roof over your head and a floor under your feet. Don’t forget to monitor depth regularly. Depth increases gas consumption, the risk of nitrogen narcosis arises, can cause oxygen toxicity and produces a greater decompression obligation. This is why many cave divers use Normoxic or Hypoxic Trimix mixtures for deep cave exploration.

Distance

When a problem arises we realize it’s a long way back. Distance, in this instance, may produce additional time-pressure stress. In worst case scenarios, your gas supply may be compromised if one team member experiences gas failure. Training and awareness, combined with careful planning, will enable you to deal with the hazard of distance. The ceiling over your head prevents direct access to the surface. This is why highly reliable equipment combined with redundancy is used for cave diving.

Changes in respiratory patterns, such as response to mental and physical stress will also increase gas consumption. When divers slow their pace, gas consumption is reduced. Never forget that your exit speed must match your entrance pace. You must cover the same amount of ground in the same time “coming out” as “going in” to insure you won’t run out of gas.

Air and Team Management

Since dive teams are obviously composed of individuals, a “ team gas management ” rule must be established. This rule incorporates all the factors involving individual considerations with another dimension. This dimension is created by people working together. When diving alone, dive techniques and gas management are different as if diving as a team member of a dive team.

The size of the dive team will dictate effective gas management. Obviously a two person dive team is the most efficient from a dive performance standpoint. It needs less communication and requires less choreography. Both divers know where their partner is. Swim pace is easier to regulate. A small team reduces the level of environmental management needed. For example, silting is just one of many factors that’s easier to anticipate and prevent.

However, there are strong arguments to support the advantages of a three person dive team. The group gas supply can go much further when shared between three people. Two people are usually better able to rescue an individual in trouble. Irregardless, the gas plan to be used must be developed from a swimming based surface rate ( vs. a resting rate ). It must be fine tuned by adjusting anticipated gas consumption against the environmental factors you expect to encounter. Experience has taught us this method is almost always totally accurate for planning dives involving a lot of swimming. To do this right, all dive team members must know their individual RMV’s.

Even with proper gas matching, it is still imperative that all dives remain within normal parameters for these rules to work. When conducting cave diving on your own, or with new team members, it is advisable to add a couple of hundred psig / dozen bars to any turn around point and turn around earlier. This practice should be continued until divers have sufficient experience to develop the discipline to function normally under stress.

Running out of Air

By taking corrective actions with gas supply problems, for example, before things escalate, divers can begin sharing gas before the diver with the problem actually runs out completely. This is good stress management. It allows the distressed diver to use his or her own gas whenever a restricted or hazardous point in the dive is reached and share air in the long, unobstructed passages. Once any member of the dive team is using a back up regulator, the dive should be terminated. All divers should begin their pre-planned exits.

Stage cylinders are generally used in addition to “back mount” cylinders or in addition to “side mount” cylinders while cave diving.  The reasons that cave divers, wreck divers and technical divers use stage cylinders include but is not limited to increase the total volume of gas during a dive so that penetration distances or dive times can be greater, to hold different gas mixes (for example a decompression mix, a travel gas, or a bottom mix), to hold a volume of gas needed for team planning or as a safety bottle, and to provide an open circuit bailout source during Rebreather diving applications, to provide safety air volumes needed when planning dives using DPV’s and calculating for failures requiring a swim out.  The diver throughout the entire dive may carry these cylinders, depending on the objective and dive plan, or they may as well be placed along a cave or anchor/ascent line to be retrieved during the exit from the dive depending on the environment and conditions they are diving. 

Diving with single and multiple stages in the overhead environment (cave, wreck, or decompression) should only be attempted by divers who have perfected diving skills in their back mount or side mount gear.  These advanced techniques are to be used only once a diver has achieved perfection in the environment they are diving and have a real need and desire to progress greater into the dive.  The reasons divers use stage diving techniques may be enticing but as well with these practices comes a greater responsibility and greater risks for divers to be aware of.  Divers are now entering further into the overhead environment, they may be leaving tanks in water filled caves which may impact the cave, and they are increasing task loading during the dive while making a more complex dive plans.  Divers using the techniques and information in this manual must as well understand and completely accept the risks involved in planning extended penetration dives.  

Stage bottles need to be secured to the divers harness via clips to the d-rings. The preferred clip is a bolt clip made out of stainless steel due to a longer life span and ease of use while brass clips become more difficult to operate with time. The size of the clips is depending of the environment, where cold water divers need larger clips due to the gloves or mittens worn. A carry strap can be attached to the stage bottle with the two clips firmly attached to the strap. The strap is used below water to handle the tank and less for the surface. A stainless steel clamp covered in a tubular webbing makes a perfect tank band to hold the strap in place. The connection from tank to clip should be of a cutable kind, a metal to metal connection is not desirable since it can not be cut in case of a clip failure or entanglement scenario when it becomes important to drop or remove the stage tank to solve the problem.

All stage tanks should be labeled clearly in regards to what breathing media is inside the tanks, the marking of maximum operational depth on the side of the tank in large number does have the advantage of the team members being able to see and verify that the correct breathing mixture is being used ant the correct depth.

Each stage regulator does need its own pressure gauge with a preferable short high pressure hose of about 15 cm length. The gauge is bend upward during use and attached to the first stage via a bungee cord or surgical tubing. During periods of non use the gauge can be released to ease the stress on the hose. During the dive when the stage bottle is not in use the valve is to be maintained close, during descent and at maximum depth the valve should be opened shortly to pressurize the first stage, a prevention of water entering the first stage due to pressure differences.

Safety and Deco

Decompression diving and accelerated decompression schedules are in need of a variety of breathing gases ranging from bottom gases to travel gases and a variety of decompression gases. All these breathing media have to be planned, blended, labeled, analyzed and then used at the appropriate time and depth during and according to the dive plan. Depending on the environment dived and the planned bottom times stage tank size and material are of consideration to the diver, while most divers prefer aluminum stages because of their lesser weight and lift requirements.

In ocean drift diving and wreck diving scenarios the decompression stage bottles are usually carried by and with the diver throughout the whole dive, even if that means that the breathing mixture is carried below safe breathing depth. In cave diving scenarios the decompression stage bottles are clipped to the line in a way that not to much stress is exerted onto the line and left at a depth where the breathing gas can be safely breathed, eliminating the potential danger of breathing the wrong mix at the wrong depth.

Extended Penetration

Stage diving must be well thought out. Staging allows the diver to extend the distance of safe exploration. Due to being further into the system it may also produce additional time pressure stress. Training and gradual build up in penetration distances will help offset this stress. In addition stage diving is similar to flying a airplane in that the diver must think well ahead of their position. By thinking ahead and being familiar with stage techniques the diver avoids delays during stage drops and retrievals and the diver will also avoid sudden changes in buoyancy.

Stage and multi-stage diving are other techniques used to further penetration into the caves or wrecks but allows as well longer bottom times during technical dives. When a diver reaches his turnaround pressure but wishes to further penetrate the cave or wreck then a stage or extra tank becomes a necessity. A stage tank can be worn on either side or all on the left hand side depending on configuration preferences. The dive is generally started on the stage tank and when the pre-established turn pressure is reached the diver switches over to another stage or the primary tanks either back mounted or sidemounted. When turn pressure on the primary tanks is reached the diver will turn around and will find his or her stage that was clipped to the line, then change over to the stage tank and exiting the cave or wreck breathing of the stage tank or tanks. Stage diving has a potential high impact on the cave and wreck environment and damage can be extended far into the cave or wreck. Care should be taken not to harm the cave or wreck. Special training is needed to use stage tanks safely in the cave or wreck environment.

Gas and Stage Switching Procedures

How you and your team will switch between your cylinders during the dive needs to be preplanned and practiced in open water situations prior to attempting them in the overhead environment or in real decompression situations.  There are a few common and ¨accepted¨ ways that this can be accomplished.  However your team decides to accomplish gas switches it needs to be remembered that there are many things that can go wrong when switching gases and going to and from regulators.  The end result of an improper switch can end in loss of gas, loss of a way to deliver gas, hypoxic and hyperoxic situations.  Gas switches no matter how done need to have the entire teams attention at 100%.  This is true if you are doing a switch to a bottom gas, travel gas, or a decompression gas.  In addition to verifying your own gas supply and system you must also verify that the other members of your team have made a proper switch as well.

Entire team switching gas and stages

One way that teams prefer to switch gases is the entire team switching at once.  This means that at one point, after the signal has been given and confirmed by the entire team, every member of the team will initiate and switch gases at the same time.  The sequence for this is:

a.     One team member gives signal to switch gases upon arrival at the correct depth or point of dive

b.     Team confirms the need and place to switch

c.      Every diver locates proper cylinder

d.     Divers read labels and check depth vs. MOD

e.     Everyone turns on the correct stage cylinder

f.       Divers deploy regulator of stage and get it into position to breathe

g.     Purge regulator you are planning to breathe from, confirm it will supply gas

h.     Switch to new regulator and breathe prior to storing previous gas (you may need to go back to it)

i.        Store hose that is no longer needed

j.       Trace regulator back from your mouth to the stage bottle and check mix and MOD vs. your actual depth

k.     Check other team members to verify they are doing switches and to proper tank and breathing gas

l.        Once all team members have switched and confirm okay, continue dive or decompression

This type of switch is best accomplished with all the team members facing each other.  While you are completing each of your steps you are as well going to be keeping up to date with what the rest of the team is doing.  How is their buoyancy, are they at the correct depth, are they switching to the correct tank, is the tank on, is somebody out of gas?  The ability for every member of the team to be able to see each other and the cylinder that each member switches to is critical.  A wrong switch to a wrong tank and breathing gas is a life-threatening event for every member of the team.  Every team member must stay in complete control of the procedures during this time of task loading. 

Individual Gas Switches

The second style of gas switching is very similar to the first in the stops but has a different team strategy.  Some teams prefer to switch with one person always acting as observer.  This means that one person will delay their switch and act as an observer until the rest of the team has confirmed their switch.  Upon confirmation of the gas switch of the rest of the team this diver will then switch gases with the rest of the team observing them.  This second way will take a longer time to get the entire team switched but gives you the added benefit of always having one diver less task loaded and paying attention to confirm the switch of the other team members and can respond in case of any failures.

a.     Team member gives signal to switch gases upon arrival at the correct depth or point of dive

b.     Rest of team confirms the need and place to switch

c.      Rest of team locates proper cylinder (leader does not switch)

d.     Team read labels and check depth vs. mod (leader observes)

e.     Team turns on the correct stage cylinder (leader observes)

f.       Team deploy regulator of stage and get it into position to breath (leader observes)

g.     Team purges planned next regulator, confirming it will supply gas (leader observes)

h.     Switch to new regulator and breath prior to storing previous gas (leader observes)

i.        Store hose that is no longer needed (leader observes)

j.       Team traces regulators back to the stage bottle and check mix and mod vs. actual depth (leader observes)

k.     Team members verify they are done with switch and to proper tank (leader confirms or makes any adjustments needed)

l.        Upon completion and confirmation of the entire teams successful switch the team leader will then start at the top of the list and complete theirs with the rest of the team acting as observers.

Once the team leader has switched and now the entire team is on the new breathing gas and or stage tank the dive will continue or the decompression will start.

Either way that you decide to switch gases team members must be responsible for their own switch while ensuring the safety of the other team members.  Regulators will be coming out of mouths making potential out of air situations more likely.  In situations of reduced and zero visibility extreme caution must be used, especially when you are carrying mixes that have maximum operating depths shallower than any parts of the dive.  A wrong switch has been the end of divers lives on more than one occasion, usually involving switches to high oxygen content tanks at depths over maximum operating depths.

Tanks

Configurations vary but easy deployment, easy location and identification has to be of paramount importance. Double tanks with isolator manifold are commonly used, however in recreational diving independent tanks are used. A sufficient quantity of gas must be carried by the diver to allow completion of the planned bottom time, utilizing the minimum gas management rule for the type of diving enrolled in. Furthermore, this gas supply must allow for gas matching between divers.

The first item that needs to be addressed in tank selection for a specific dive is the needed gas supply and with it tank size resulting from factors such as body size, gas consumption, planned depth and duration. Experience has taught that the most logical approach to the question of gas supply can be best summed up by the statement in why there is a need for gas supply requirements. The first step in planning a dive involves computing the amount of gas needed for the dive. This includes primary mixes and decompression mixes. Decompression systems should provide a sufficient volume of gas to complete all appropriate stops with a minimum reserve supply. Each decompression gas cylinder must be appropriately marked as to its use, breathing gas and M.O.D. It’s also suggested that regulators be color coded or coded for easy identification. Mouthpieces should be protected to prevent from accidentally being used with the wrong mix during your decompression at the wrong depth.

The choice between tank materials will be dedicated by the environment and thermal considerations. The diver should be balanced in a way that he or she is neutrally buoyant with empty tanks at 10 feet / 3 Meter, comfortable for prolonged periods of time. In order to archive this diver must balance and trim their rig carefully for the environment one is diving in. Ample emergency gas volumes must be carried for the type of diving engaged in plus a redundant buoyancy device such as a dry suit or back up BCD must be worn on deeper dives.

Steel Tanks

While steel tanks are a great choice for cold water, wreck or cave diving due to their larger volume 104 or 121 cft / 15 or 18 ltr where the weight of the tanks is partially offset by the thermal protection due to dry suit sworn by most divers. Helium based breathing gases do affect weight and buoyancy underwater and must be taken into account.

Aluminum Tanks

Warm water, wet suit ocean diving is best done with aluminum 80 cft / 12 ltr tanks due to their lesser weight and with it lesser negative buoyancy at the bottom phase of the dive. If more gas is needed a aluminum stage tank should be added to fulfill breathing gas requirements.

Harness and Backplate / Softpack

While many dive gear manufacturers offering traditional BCD’s for recreational diving most wreck, technical or cave divers prefer the harness and backplate / softpack combination. Most recreational BCD’s can not be adapted for advanced forms of diving such as cave, technical and wreck diving and when a diver is ready to proceed to higher levels of training a new set of gear has to be purchased. Harness and backplate / softpack combinations eliminate that problem since they can be easily adapted for single tank recreational diving or technical and cave diving activities that may lay n the future.

Harness

A harness is used to attach the tanks to the diver sandwiching the wing style BCD between the tanks and the harness. The harness is attached to a backplate or a soft pack, which is then attached to the single or double tanks. A wing style buoyancy compensator has to be worn, attached to it a low pressure power inflator. The webbing attached to the backplate should be of the all through type with no connections, easy clips, rings or fast buckles intersecting the webbing. Such fasteners who make it easier to get into and out of the diving rig are potential failure points with disastrous potential to loose all of the equipment during the dive and in the long run it is more economic to change a basic webbing when it is worn out.

The crotch strap that has to be worn in order to prevent the unit from “riding up” should be without a clip but made from the closed loop type in order to prevent breaking clips during or prior to a dive. Crotch straps can be used as we for gear storage when a d-ring is attached to it at the back, or to attach a scooter to a d-ring in the front. The all one through webbing allows as well the placement of d-rings at any location throughout the harness to accommodate backup lights, stage tanks on the chest d-rings and gauges or reels on the waist d-ring.

Backplate

Backplate’s are made out of ABS plastic, aluminum or stainless steel. The stainless steel backplate is the most popular one since it is a little heavier and compensates for some of the weight a diver may needs to carry when diving with positive tanks or a dry suit.

Soft packs

The softpack harness systems on the market have the advantage of being well adaptable for the type of diving one is involved in ranging from recreational single tank diving to technical, wreck or cave diving to advanced forms of cave diving such as sidemount diving. The potential downside is the fast clips on the chest that could a dive fast out of the rig but could fail before or during a dive and be difficult or impossible to repair.

Buoyancy device

Back mounted wing style wing’s are known for superior trim characteristics in recreational openwater diving and advanced diving while openwater style BCD’s are not recommended due to limited lift capabilities, buoyancy characteristics, tank attachments and d-ring placement specially in advanced forms of diving such as technical, wreck or cave diving. The lift of the wing needed is depending on equipment weight, tank weight full and empty,  scooters and stages if worn. Oversized wings and tight bungeed wings do have a tendency to create more drag in the water resulting in more energy spend and potential exhaustion of divers. All wing inflator and dry suit inflators if used should have the same connector to insure interchangeability of hoses and gas supply.

Wing style BCD

Wings are coming in a variety of lift capacities, styles and some sport a choice of features. The chosen wing should have the right amount of lift for the equipment, tanks and environment dived in. The corrugated hoses should be not as long as to touch the floor when diving close to the bottom and stirring up silt, damaging the environment or entangling the diver. Shorter size corrugated hoses are available to change the log size hose. In demanding environments such as inside wrecks or caves it is a good idea to have the inner bladder protected against puncture. Dump valves in the corrugated hose assembly can fail and present a potential problem. Dump valves on the bottom of the wing should be streamlined by cutting of the plastic knob to prevent entanglement.

Back up wings are recommended in deep dive applications or a dry suit can be used as a back up buoyancy device however dual bagged bladders are potentially creating added drag and degrade performance, this will in the end may slightly increase in gas consumption. The advantage of a dual bladder in the event of a BC failure is that the diver may still function normally and make a safe ascent. Diving with a single bagged bladder provides less drag and maximizes performance. Given a choice, most divers would prefer a configuration that reduces drag. But, if there’s a chance the single bladder could fail and this failure could be life threatening, it makes good sense to sacrifice being streamlined by increasing redundancy. By opting for greater redundancy, divers need to recognize this will increase their gas consumption. They must also realize it’s going to slow them down a little. Keep in mind dry suits can be used as a backup buoyancy control device.

Lift

Depending on fresh water or salt water diving, choice of tanks used, including exposure suit selection the amount of weight can vary greatly. Carrying to much weight should be avoided while conducting buoyancy checks before diving activity striving for a balanced rip that can be use with neither to much weight or to much gas in the lifting device. Drop weights can be used in stable depth caves and left close to the entrance when maximum depth is reached. V-weights can be used for double tanks used in-between double tanks and kept in place by the wing and harness while weight belts should be avoided.