Presentation on theme: "Dry Suit Diving Part 2: Techniques"— Presentation transcript:
1 Dry Suit Diving Part 2: Techniques This PowerPoint presentation was compiled by Terrence M. Rioux from the following sources:Barsky, S. The NAUI Dry Suit Diving Specialty Course National Association of Underwater Instructors. Montclair, CABarsky, S., D. Long, B. Stinton Drysuit Diving – A Guide To Diving Dry. Watersport Publishing, Inc., San Diego, California.Long, R., M. Flahan Instruction Manual and Backup Materials – DUI’s Dry Suit Instruction Program. Diving Unlimited International, Inc. San Diego, CAScales, T. Dry Suit Diving Powerpoint British Sub Aqua ClubSellers, S. Dry Suit Diving PowerPoint East Carolina UniversityT. Joiner (ed.) NOAA Diving Manual - Diving for Science and Technology, Fourth Edition. Best Publishing Company, Flagstaff, Arizona.Photos attributed to Mr. Steven Barsky are from the NAUI Dry Suit Diving Course slide set, 1994.With emphasis on the use of the CF200 dry suits manufactured by Diving Unlimited International, Inc. (DUI)Photo by Steven M. Barsky
2 Training Goals Upon completion of this session, the student will be able to: Discuss the importance of Boyle’s law with respect to dry suit divingDescribe how to determine proper weightingList normal predive procedures.Describe how to inspect, prepare, and don the dry suit.Describe the proper way to enter the waterDescribe how to begin the descent and how to control the descent.Describe how to control buoyancy at depthDescribe how to control buoyancy during ascentDescribe how to maintain buoyancy at the surface
3 Training Goals, Continued Upon completion of this session, the student will be able to: Discuss dry suit leaks, their cause and preventionDescribe how to remove a dry suitDescribe normal post-diving procedures and proper storage of dry suits.Describe proper maintenance of dry suitsDiscuss the problems associated with diving in extremely cold waterList and describe emergency proceduresInflator and exhaust valve problemsLost weight beltFlooded suitUncontrolled ascentInverted ascent
4 A dry suit is not just a piece of clothing to be worn; it is a buoyancy device that the diver must control.
5 Review of Boyle’s Law Depth 0 feet 33 feet 99 feet 66 feet 2 ATM 3 ATM Air VolumeAbsolutePressure1 ATM11/21/31/4Volume of a gas is inversely proportional to pressure
6 Pressure and buoyancy Diver in a dry suit is surrounded by air Air changes volume as pressure changesAs diver sinks …pressure increasesair compressesvolume gets smallerbuoyancy reducessinks even fasterAs diver rises …pressure decreasesair expandsvolume gets biggerbuoyancy increasesrises even faster
7 Pressure and buoyancy Controlling the suit … Inflate on descent to avoid squeeze and slow rate of sinkVent air on ascent to slow rate of riseNote how easy it is to lose control …Vicious circle during both sinking and risingRate of sink/rise increases if not correctedBiggest pressure & buoyancy changes near the surface
8 Dry Suit WeightingThe goal is to dive with the minimum amount of weight possible, resulting in the minimum volume of air inside your suit.This will simplify buoyancy control – a diver with excess weight will have to put excess air into the suit to become neutral.When this air bubble shifts in the suit it can create buoyancy control problemsWear only enough weight to allow you to make a safety stop at the end of your dive (15 – 20 ft) with 500 psi of pressure in your cylinder.
9 Estimating Weight Requirements Generally, you will need 4 to 10 lbs more weight than you wear with a 7mm wetsuit. How much weight you need depends on a variety of factors including:The type of dry suitThe type of undergarmentYour personal buoyancyThe type of cylinder you useAll cylinders become more buoyant as the air inside the tank is usedHow much more depends on the cylinder material and volumeWhether you’re diving in freshwater or saltwaterMore weight is needed to dive in saltwater (Table 2 – next slide)
10 Table 2. Adjusting weight from fresh to saltwater Diver’s weight* Additional weight125 lbs lbs.155 lbs lbs.186 lbs lbs.217 lbs lbs.*includes weight of diver plus equipment
11 Estimating Weight Requirements Check the manufacturer’s specifications for your cylinder to see how the buoyancy changes from the time the tank is full until it is empty. This change in buoyancy must be considered for proper weightingaluminum 80ft3 Luxfer and Catalina tanks become approximately 6 lbs. more buoyantFaber steel 98ft3 tanks become approximately 8 lbs. more buoyant
12 Checking BuoyancyPlace regulator in mouth and breathe normally. Vent all the air out of your BC. You should still float.Vent any remaining air from dry suitIn a vertical position – you should float with your eyes at water level with a lungful of air, and you should begin to sink slowly after exhaling all the air from your lungs.If you sink rapidly you are too negative.Add or subtract weights as necessary.Now add weight to account for the change in buoyancy of your tank as you breatheAdd approximately 2/3 the weight of the buoyancy change of your scuba cylinder from full to empty (you may find you have to adjust this slightly).You should be able to become neutral at a depth of 10 feet when you have 500psi of air in your tank.Once you have determined your buoyancy for a given suit/insulation system, make a logbook entry so you will know how to weight the next time.
13 Prediving Procedures Prepare suit Remove suit from storage bag and unrollInspect body of suit for obvious cuts, damageInspect zippers for corrosion, frayed or cracked rubber sealing surface, missing teethInspect seals for deterioration (cracking or gummy spots on latex), cuts, other damage. If using Zip Seals, ensure security of cuff/seal interfaceCheck inflator button function; if using swivel type valve, make sure it moves smoothlyCheck that exhaust valve rotates smoothly and push button to check function
14 Prediving Procedures, Continued Prepare suit, continuedLightly rub wax onto outside surface of zipperLubricate the seals with pure talcum powder (do not use scented talcs which contain oils that can damage seals). This will allow you to get through seals easier. Soapy water may be used as well.Remove all watches and jewelry including earrings, necklaces, bracelets and rings. Any of these may tear a dry suit seal.Photo by Steven M. Barsky
15 Prediving Procedures, Continued Assemble and inspect other equipmentFins large enough to fit over dry suit bootsBC large enough to fit over dry suitDry suit l.p. inflator installed onto regulatorAssemble all undergarment components and inspect (zippers, Velcro, etc.)Rock boots, if usedInspect and assemble all other SCUBA equipment as usual
17 Donning a Dry Suit Put on undergarments Invert top of dry suit down to crotchSit downArrange suspenders behind the suit so they don’t get tangledInsert legs, making sure that your socks/booties don’t fold over your toes (they will cramp during the dive!)If your suit has ankle straps, secure them. If your suit has rock boots, put them on and lace themPut on ankle weights if you choose to wear them.Pull up bottom, arrange and adjust suspenders over shoulders
18 Donning a Dry Suit, Continued Extend torso, put arms into sleevesWhen putting hands through wrist seals, extend fingers (including thumb) and squeeze them together – this will give your hand the smallest diameter for getting through the seal.With your free hand, either grab the outside of the wrist seal and pull it over the hand inside the suit, or alternatively, slip two or three fingers of the free hand inside the opening of the wrist seal and pull the seal over the hand inside the sleeve. In either case, do not dig your fingernails into the seal.Ensure no undergarments extend through wrist seal.Ideally, at least two inches of seal should be in direct contact with your skin.Photo by Ray SharfPowdering the seals greatly eases the donning process.
19 Donning a Dry Suit, Continued To spread the neck seal, reach through the seal with both hands and spread the neck seal by pulling against the palms of your hands. Avoid digging your fingers into the latex.Pull the neck seal over your head.Photo by Steven M. Barsky
20 Donning a Dry Suit, Continued Ensure that long hair and collars are not caught in the seal.Neck seal should lie flatPhoto by Steven M. Barsky
21 Donning a Dry Suit, Continued Close waterproof zipper, making sure that you check to make sure that the glider is fully docked onto the rubber stopIf your suit is equipped with a zipper guard, zip that as well.Fold telescoping torso, secure and adjust the crotch strapInsure both inflator and exhaust valves work before entering water.Photo by Steven M. Barsky
22 Donning a Dry Suit, Continued Vent the suit.makes the suit more comfortable to wear on deckprevents air from escaping from the neck and creating a leak upon entering the water.Squat down, cross your arms over your chest and either manually open the exhaust valve, or let air out through the neck.Close the exhaust valve by rotating clockwise until it stopsPhoto by Steven M. Barsky
23 Entering the Water Perform normal buddy checks BC should be used for surface flotationYou will notice 2 things when you enter the water:No icy streams of water entering your suit! Nice!When vertical at the surface, you will feel the suit compressing your feet and legs as the air migrates upwards
24 Diving a Dry Suit – Check for Leaks Do not dive if your suit is leaking. Upon entering the water, take a moment to check for leaks. If you feel water coming in, take the time to fix the problem – a small trickle on the surface may get worse at depth, and will certainly continue throughout your dive.
25 Diving a Dry Suit – Starting the Descent Vent all the air from your BC.Open automatic exhaust valve by rotating it all the way counterclockwise. Leave it open throughout the dive.Lift your left shoulder (thereby making the exhaust valve the highest part of the suit) while keeping your arm bent and your hand pointed towards the bottom. You will hear air hissing out of the valve.Exhale, and if you are weighted correctly, you will begin to sinkPhoto by Steven M. BarskyThe bubble to be vented must be directly below the exhaust valve.
26 Diving a Dry Suit – Descending As you sink through the water column you will begin to feel “squeeze” on your body. Add just enough air to relieve the pressure and control your descent using short bursts.Be aware of the position of your exhaust valve. Lower your left shoulder to retain air and raise it to vent air.As you near the bottom shift to a horizontal position to avoid stirring up sediment.Photo by Steven M. Barsky
27 Diving a Dry Suit – Controlling buoyancy Maintain a minimum volume of air inside the suit – there should not be a large bubble of air inside your suit, nor should you notice massive air shifts as you change positionControl buoyancy at depth using only your dry suit. Do not add air to your BC to control buoyancy – it is very difficult to control buoyancy in 2 separate compartments simultaneously.Maintain a constant awareness of the state of your buoyancy
28 Diving a Dry Suit - Ascending Ensure that automatic exhaust valve is open before ascending.As you ascend and gain positive buoyancy, raise left shoulder so valve is higher than rest of suit. Keep your lower arm pointed down -Do not extend the rest of your arm higher than the valve or air will rise to your wrist and bypass the valve.Control buoyancy by raising and lowering position of exhaust valve. You should be able to stop and hover at any time during the ascent.If you find you are ascending faster than you should, raise the valve higher and air should vent faster. If air still isn’t venting fast enough, vent the valve manually by pushing down on the valve.Photo by Steven M. Barsky
29 Diving a Dry Suit – On the surface Upon reaching the surface, close the exhaust valve at the surface by rotating it all the way clockwise.Inflate your BC at the surface – it is more comfortable to move on the surface this way rather than inflating your dry suit.If the dive is over, exit the water as normalBecause of heavier dry suit weight systems, when diving from a small boat:If using a DUI Weight and Trim System or weight integrated BC, pull each lanyard and hand weights up, or hook a snap from a boat lanyard and remove entire systemAlways remove weights before removing air/BC system
30 Dry Suit Leaks All dry suits leak a little. When the suit is closed up, the humidity inside raises to 100%. Even when not perspiring, moisture is constantly coming from the skin pores. Body heat moves the moisture to the cool inside surface of the suit where it condenses. It is common to find moisture on the inside of the suit after a dive.Flexing your wrists and turning your head allow water to enter around pronounced tendons. This is normal, and can be avoided with knowledge and practice.Remember, “damp is OK as long as you are warm.”
31 Removing a Dry SuitIf you suspect that you have a leak in your suit, undress carefully and assess where the wet is as you undressUnfasten crotch strapUnzip zipper guard if installed. Unzip waterproof zipper.Simultaneously tuck your chin to your chest while sliding the fingers of each hand down between your neck and the seal. Grasp firmly (careful with fingernails!) and spread the neck seal with your hands, lifting the seal up over your head.Slide left hand out of seal (insert 2 fingers of right hand under the wrist seal with the fingernails against the wrist, slide the fingers of left hand down past the seal, grasp the sleeve of the suit, and pull your left arm out of the sleeve). Carefully shrug off shoulder and remove arm.Remove right arm from sleeve.Invert suit down to crotch and pull off suspendersSit downRelease ankle straps if installed, rock boots and ankle weights if usedGently place the toe of one foot on the heel of the other, point your toe and pull out of the drysuit leg. Repeat with the other foot.Instructions specific to the DUI front self-donning dry suits with latex zippers.
32 Post-dive ProceduresRinse all equipment in fresh, warm (if available) water as normalOperate valves as you run water over them – rotate automatic valves and push the inflator button several times.It is usually easier to hose the zipper while wearing the suit, but if you remove the suit before washing close the zipper and the seals with rubber bands first to prevent water entry.If suit or seals have been contaminated by oil, gently wash with mild soapy waterPhoto by Steven M. Barsky
33 Post-dive Procedures, Continued Hang suit over a large diameter roller in a dry location away from direct sunlight, ozone, high heat, etc.Remember also to turn the suit inside out to dry (keeps the mold and smell down)When fully dry, roll as per owner’s manual instructions and store in dry suit bag.Photo by Steven M. Barsky
34 Storage of Dry Suits Store in a cool, dry, dark place Store away from heat, chemicals, petroleum, solvents, electric motors and other producers of ozone – ozone deteriorates latexAvoid storing in direct sunlightCover valve stemStore rolled in the proper drysuit bag or flat, never folded (can develop permanent creases) or on a thin metal hangar (creases and rust)Do not bend zipper in storage – store suit with zipper open to avoid creating a permanent compression set on the sealing surface and reducing the life of the zipper.
35 Maintenance of Dry Suits Zipper lubrication – zippers should be lubricated either before or after you dive. Use bees wax or paraffin wax – never use silicone spray or grease on your dry suit zipper. (Also, be sure to remove any excess paraffin wax – otherwise it will cause deterioration of latex seals if let in contact with the seal for long periods of time)Close the zipper and only lubricate the outside – if you lubricate the inside dirt will collect and cause the zipper to fail.A thin film of wax is sufficient
36 Locating leaks Close seals with rubber bands and close zipper. Assemble regulator and cylinder with dry suit inflator attached. Turn on air. Attach inflator to suit and push button just enough to lightly inflate suit.Brush soapy water and observe any bubblesMinor leaks can be repaired with Aquaseal and Cotol. Suit must be completely dry.Major leaks or damage should be returned to dealer or factoryPhotos by Terrence M. RiouxNote: the pictures illustrate Viking vulcanized rubber dry suits. Vulcanized rubber suits are repaired by patches very similar to innertube patches.
37 Lifting Heavy ObjectsDo not lift heavy weights by inflating your dry suit or BC – if the weight drops you will become dangerously buoyant.Use proper procedures, such as lift bags or lift lines to raise heavy objects.Photo by Steven M. Barsky
38 Polar and Ice DivingWater colder than 39°F (4°C) is an extreme environmentAn unprotected person (i.e., falling over the side, major dry suit leak) will be rendered helpless within minutes and this will result in a life-threatening situation.Equipment problemsSCUBA regulators and inflator valves may freeze, resulting in severe free-flowLowered battery life (e.g., computers, lights)Many materials become stiff or brittle in extreme coldWinter (February is coldest month) in New England approach polar conditionsDiving under an ice ceiling is an advanced skill and requires special training and equipmentPhoto by Judy Harbison
39 Regulator FreezeupCompressed air released from first and second stage valves is cold because of adiabatic coolingThe colder the water, the more readily ice formsExhaled breath is saturated and may freeze on valveHeavy exertion and breathing increase coolingIce forms, preventing valve from seating and creating a free-flowFree-flow increases cooling, resulting in more ice formation, resulting in uncontrolled free-flowBC and dry suit inflator valves also susceptible to freezingPreventionSecond stage must be completely dried between divesAvoid breathing into regulator until you leave the surfaceAdjust any small air leak before beginning diveBreathe slowly and calmly during diveSome brands/models have better cold resistance than othersConsider using completely redundant systems in very cold water (‘Y’ valve or pony bottle) Inflate BC & dry suit using short burst, not longAbort dive if you detect any leaks
40 Severe regulator freeze-up Ice completely filled second stage due to uncontrolled free-flow. Obviously, the cylinder was emptied very quickly.Icing around the first stage, however, is normal in very cold water.Photos by Terrence M. Rioux
41 Emergency Procedures Inflator valve stuck open Causes Corrosion, silt or sand buildup in valveFreezing causing ice to build up in valveThis will cause your suit to inflate continuously.immediately attempt to disconnect your inflator hoseAssume proper position and vent excess air through the exhaust valveIf severe enough, pull neck or wrist seals open (water will enter suit)If air cannot be vented, extend arms and legs in a horizontal position to create drag (flare position)Note: In exhaust valve management, it is assumed that the diver is using an automatic exhaust valve. If using an old-fashioned push-to-dump valve (e.g., diving the Unisuit), the diver would need to disconnect the inflator hose, assume a position with the air bubble to be vented under the valve, and press the exhaust button.
42 Emergency Procedures Inflator valve stuck closed Cause: poor maintenance and corrosion build-upThis should be detected during the pre-dive inspection!If it does happen on the dive:Stop the descent and terminate the diveUse BC as needed to control buoyancyReturn to the surface venting expanding air as normalRemind yourself to do a better job during the pre-dive inspection next time!
43 Emergency Procedures Exhaust valve stuck closed or clogged Cause: improperly maintained valveA very rare occurrenceResult: exhaust valve may fail to exhaust airIf your exhaust valve fails, you should immediately stop your ascent, if possible. Rotating or manually operating an automatic valve may get it to work.If your valve still does not function properly pull neck or wrist seals open to vent – you will get wet doing this.ascend an anchor line or some other fixed objectLittle can be done to get a push-to-dump valve to work properly once clogged.
44 Emergency Procedures Leaking exhaust valve Cause: dirt, lint, sand buildup in valveDetermine extent of leak, terminate dive if neededUse BC to control buoyancy if necessary
45 Emergency Procedures Dropped/lost weight belt at depth If unable to recover weights, you will become very buoyant and ascend very rapidlyIf you are right next to an anchor line or fixed object, hold on and try to shimmy up.Exhaust expanding air as rapidly as possible and vent from seals.If ascending rapidly, use flare position to slow ascent by increasing dragRemember to exhale!
46 Emergency Procedures Rapid ascent Flare position: you may slow your ascent dramatically by holding your ankles rigid with your fins parallel to the bottom (the fins act as “water brakes”), arching your back, and holding your arms out parallel to your body.Another technique for slowing a rapid ascent is to swim horizontally, so your body presents a greater surface area.
47 Emergency Procedures Righting yourself It is possible for excess air to move to the feet of your dry suit, potentially making it difficult to return to an upright position.To right yourself in this situation, tuck your body into a ball, give a slight kick, and roll to an upright position. Once you are upright immediately vent your suit through the exhaust valve to regain control.Photo by Steven M. Barsky
48 Emergency Procedures Complete dry-suit flooding Occurs only rarely, possibly from the complete failure of a zipper, blow out of a neck seal, or the destruction of a valve. Total flooding of your dry suit may cause you to become negative depending on what kind of undergarments you are wearing.Usually you will be able to achieve neutral or positive buoyancy by inflating your BC.A flooded dry suit may make it extremely difficult to exit the water – someone may have to puncture the leg of the suit to drain water.
49 WHOI Dry Suit RulesCertification from DSO must be obtained before usage.Advance notice via dive plan must be given.Dry suits must be signed out – and in - when returned.Project may be liable for any damage incurred due to user negligence.Dry Suits will be properly cared for, cleaned and dried before storage.Always clean at end of diving day, just as you would with personal diving equipment.Hang up to dry both inside and outside.When dry, please store in the proper bag (they are marked) and put away.Please keep the inflator hoses with the dry suits; do not leave them on the regulators.Keep track of all of the components, including booties, hoses inflator plugPlease return the powder bags and wax!Dry suits may not be loaned out to unauthorized persons.
50 ReviewWhy is Boyle’s Law so important to learning how do dive in a dry suit?How do you determine your proper buoyancy?How do you prepare a dry suit for diving?List the steps involved in donning a dry suit.Before entering the water, what is the position of the exhaust valve?How do you start your descent?What is the role of the BC in dry suit diving?
51 Review, ContinuedHow do you control buoyancy while descending? While ascending?What two steps do you take when you first reach the surface?List the steps in removing a dry suit.List at least 5 maintenance procedures.How can you reduce the incidence of regulator and inflator valve freeze-up when diving in very cold water?What do you do if your inflator valve gets stuck in the ‘open’ position (can’t turn off the air)What do you do if you are rising with your feet above your head?