1. Dry Suit Diving Techniques

2. Objectives
To develop the student’s knowledge of dry suits - When to use dry suits, types of dry suits available, their maintenance
To develop the student’s ability to perform effectively in a dry suit
To enable the student to plan, organize and conduct SAFE operational dives
Upon completion of the classroom training, the student will be able to:
Describe the planning and organization of a dive utilizing a dry
suit
Describe the types and styles of dry suits available
List the features found on a typical dry suit and the appropriate
supporting accessories
Describe the suitable insulation combinations for various water
temperatures and determine your personal needs
Explain the problems or hazards associated with using a dry suit
and explain how these may be avoided or overcome
Explain the safety procedures to be used while diving in a dry suit
Describe equipment concerns and integration for dry suit diving
Describe causes of leaks, their identification/recognition and their
prevention
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3. Why Dive a Dry suit? Environmental protection Thermal protection
Physiology of cold exposure
Unearned fatigue
Increased bottom time - cold, air consumption
Diver Performance - comfort and safety

4. Environmental Contaminants
Biological
Chemical
Nuclear

5. Minimizes Exposure to:
Gasoline & oil
Sewage & waste water
Agricultural run-off
Human tissues/body decomposition
Bacterial infection

6. Thermal Protection
With proper insulation, dry suits provide excellent thermal protection in cold water.

7. Advantages of Diving Dry vs. Wet

8. Wet Suits (Foam Neoprene)
Insulating ability determined by thickness of suit
Insulation and buoyancy
DECREASE with INCREASING DEPTH
Allows skin exposure to contaminants
Allows water against skin (Cold)
Requires a good fit
Must dry before repair
Wet Suits
Foam neoprene
Max insulation determined by thickness of suit
Insulation decrease with increasing depth
Buoyancy decrease with increasing depth
Requires perfect fit
Degradation of performance with use
Drying time requirements before repair
Cold water against skin - uncomfortable
Increased air consumption
Wet suit performance degradation - prediction from the Personal
Insulation Guide

9. Dry Suits Control of insulation and buoyancy regardless of depth
No skin contact with water
No increase in air consumption
Rugged, longer life, more durable
Variable insulation options
Does not require perfect fit
Can be repaired quickly
Dry Suits (misnomer - most leak a little)
Rugged outer shell - longer life, more durable
Variable insulation
Insulation constant regardless of depth
Buoyancy constant regardless of depth
Does not require perfect fit
Performance does not change with use
Can be dried and field repaired quickly
No cold water against the skin - comfortable
No increase in air consumption
Dry suit performance constant regardless of depth - prediction from the Personal
Insulation Guide
Dry Suit Style and Materials
First attempt - latex
Old style
Foam neoprene
Pack cloth
Modern style
Rubber-coated
PVC
Woven fabric
Trilaminate
Polyurethane laminate
CF-200

10. Thermal Comparisons Wet Suit Dry Suit 1st 2nd 3rd 700F 100% 600F 90%
# of Dives/ H2O Temp
Wet Suit
Dry Suit
1st
2nd
3rd
700F
100%
600F
90%
80%
500F
70%
50%
400F
25% *
85%
75%
320F
55%
* Not recommended unless involved in a life-saving rescue.

11. Dry Suit History
Commercial heavy gear, which has been around since the 1890’s was the earliest attempt to keep divers dry. Long underwear was worn under the canvas suit for warmth.
Early dry suits for sport diving were not very good. They were difficult to seal. There was no way to introduce air into the suit to prevent the suit from squeezing the diver.
Commercial divers used hot water suits. Hot water is actually pumped to the diver through a hose attached to the suit.
Today’s dry suits are much better than the old dry suits. Most of today’s dry suits have waterproof zippers for easy entry and exit and low pressure inflators which allow the diver to add air to the suit.
For more information on the history of dry suits refer to the NOAA Manual

12. Dry Suits Were Originally Made From
Packcloth
Latex
Neoprene
Rubber
Types of Dry Suits
Neoprene
Fabric material
Vulcanized rubber

13. Modern Dry Suit Construction
Crushed neoprene
Coated or laminated fabric
Polyurethane laminate
Vulcanized rubber
Other special design (military)

14. Crushed Neoprene Characteristics of Neoprene Dry Suits Great stretch
Insulation varies with depth
Buoyancy varies with depth
The unisuit - a neoprene dry suit was one of the first dry suits
distributed nationally
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15. Coated Material Also known as Laminate or Tri-Laminate
A hood should be worn at all times!
Characteristics of Fabric Material in Dry Suits
Low initial cost
Little stretch
Highly flexible
Telescoping torso

16. Vulcanized Rubber for Severe Contamination

17. Vulcanized Rubber Dry Suits Offer
Good environmental protection
One piece construction
Inflation/exhaust valves
Rugged and flexible
Attached boots
Dry hood

18. Polyurethane
Offer many of the same benefits of a vulcanized rubber suit
Fast and simple to repair
Slightly less flexible than rubber suits
Lighter weight than rubber suits

19. Insulation Options Thinsulate Radiant film Open Cell Foam Polartec
Types
Pile
Open cell foam
Thinsulate
Commercial non-diving sources - mountaineering, ski, etc
Layering combinations
Determining personal needs
Fine tuning and adjusting
One piece is the most desirable when diving at deeper depths
Considerations
Thermal considerations - thickness requirements
Environmental conditions
Dives per day
Workload
Personal set point - susceptibility to cold
Dry suit fabric - preference, comfort, availability
Material - performance, comfort, availability
Style
Interchangeability
Ability to dry quickly between dives
Insulating properties when wet
Additional features
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20. Thinsulate

21. POLARTEC

22. Open Cell Foam Open Cell Foam
No longer available, but still widely used.

23. Dry Suit Care Lubricate neck and wrist seals with talc
Wax zippers, store open
Wash and thoroughly dry inside and out
Inspect for tears in seals
Inspect valves
Avoid exposure to UV rays, oil & harsh chemicals

24. Wax Zippers After Each Use
To wax, completely close the zipper, and work wax into zipper from both sides. Store with zipper open.

25. Talc Powder Unscented
All latex seals and parts should be powdered once the suit dries.

26. Hang To Dry Hang in a cool dry place to let suit dry.
You can use a towel to dry inside and put back in service.

27. Why Dry Suits Leak Zippers Seals Valves Fabric Zippers Seals Valves
Not fully closed
Damage failure
Not fully open when dressing and undressing
Sand, dirt and salt
Improper lubrication
Careless closing - undergarment snag
Overstress
Old age
Seals
Insulation garment extending under seal
Hair under seal
Folds in seal
Improper adjustment - tendons
Age cracks, tears and snags
Over-trimming
Valves
Dirty
Improper adjustment of adjustable exhaust valve
Exhaust valve stuck open (exhaust valve will exhaust air faster than inhalation port can
supply it
Minor leakage upon closing of exhaust valve
Valve not properly secured to suit
Suit/Fabric
Seam failure or chafing
Tears, punctures or splitting
Inflate valve stem
Abrasion from sitting or scraping against sharp objects
Delamination

28. Donning Determine need for thermal insulation
Smooth neck and wrist seals against skin
Zip closure
Check exhaust valve
Crouch and “Burp”
Attach Low Pressure hose
Check inflator valve
Some seals are supposed to be flat and others are designed to be folded over.
flat: bell cuff
Operational Procedures - Diving a Dry Suit
Donning and doffing
Weighting - do not overweight
Maintaining neutral buoyancy and buoyancy control
Public Safety Divers must wear a BC while dry suit diving
Suit and buoyancy control device combined
Inflating and deflating
Discussion Topic – According to NOAA, “controlling two independent flotation systems (the dry suit and the buoyancy compensator) at the same time is considered an advanced skill and requires additional training and practice.” Other considerations for wearing a BC include possible suit flooding, valves sticking and orally inflating a BC following an emergency ascent.

29. Donning Suspenders

30. Cuff Seal – Apply talc prior as a dry lubricant

31. Pull Neck Seal, Turn Head, Check Seal.

32. Pull Zipper with Finger Inside suit
Finger keep the undergarment from getting caught in the zipper.

33. Squat to Bleed Out Air

34. Use Buddy System to Don B/C
Left side first, over exhaust valve on the Dry Suit.

35. Diving Equipment Considerations
Weight systems
Buoyancy Compensation Devices (BCD’s)
First stage regulator (L.P. ports)
Fins
Weight System
Waist belt
Standard weights
Shot
Single pocket
Individual weight pouches and pockets
Maximum load
Ankle weights
Weights attached to BCD
Integrated with back pack
Ease of adjustability
Tank size commonly used
Fresh water/salt water
Go Over Weighting Hand Out
Other Equipment
Style of BC
Scuba harness and straps - location and adjustment
Regulator LP Ports
Adequate number
Location
Tanks commonly used - tank buoyancy, buoyancy swing
Fin size and strap length
Go over weighting handout

36. Important Features Attached boots Attached hoods Waterproof zipper
Attached gloves (cuff rings)
Reinforced stressed/abrasion points
Hoods
Replaceable hood and neck seals
Neck dam for Superlite Helmet
Gloves
Standard
Gauntlet
Dry
Five finger
Three finger
Hood
Warm neck
Attached
Face seal or cover
Self-venting
Full-face mask

37. Attached Boots

38. TLS seal

39. Zip Seal Gloves

40. Gloves Fit Over Cuff Ring

41. Optional Accessories Suspenders Ankle straps Telescoping torso
Knee pads
Pockets
Relief zipper
Additional Accessories
Cuff rings
Gloves
Hood liner
Neck warmer
Inflation hose
Maintenance kit

42. Customizing Your Dry Suit
Neck seal
Wrist seals
Hood
Neck and wrist seals can be trimmed to fit. Let new suits stretch before trimming them.
Unscented talc is the best lubricant for donning latex suits.
Although it is possible to “don” by yourself, a tender will ease the process and help solve many of the potential dry suit leak problems.
On shoulder entry suits, the legs go in first with the wrist next and the head last. Do not use finger nails on the latex seals or pull with excessive force.
We recommend removing all jewelry
Set the wrist seals properly, striving for a wide, smooth seal.
Spread the neck seal and pull it over your head.
The neck seal is always folded down and in on a dry suit. The seal should lie flat against the diver’s neck.
Your buddy should zip your suit, in order to prevent your underwear from getting caught in the zipper.
Open your exhaust valve, squat and force the air out of your suit.
Most divers require some additional weight when using a dry suit
compared to a wet suit.

43. Neck Ring System

44. Maintain Proper Positioning
Maintain head up/feet down orientation
Control buoyancy with BCD
Add air to dry suit to prevent squeeze
Vent excess air through exhaust valves to prevent uncontrolled ascent
Ascending and Descending
Suit squeeze
Manual valves
Adjustable valves
Buoyancy compensator
Volume of air in suit
Emergency procedures
Properly weighted, a diver should just begin to sink upon exhaling.
To descend, the diver should vent air from the suit by opening the exhaust valve until the diver just begins to sink.
The diver should add air to the suit at depth to prevent suit squeeze and maintain comfort.
Upon ascent, the diver must vent excess air from the suit. If your suit is equipped with an automatic buoyancy valve, make sure it is at the highest point.

45. Dry Suit Diving Requires Control and Composure
Dry suit operations require a strong foundation of basic scuba skills on which to build advanced level skills.

46. Emergency Procedures
Going The Wrong Way
Too Fast!!!

47. Inverted Assent

49. Knowledge of dry suit operations will help avoid potential emergencies
Learn the specific emergency procedures for these situations.

50. Emergency Procedures Inflator valve stuck open… Disconnect L.P. hose
Assume proper position and utilize exhaust valve
If severe enough allow air to escape by releasing neck or wrist seals (WATER IN)
If air cannot be vented, utilize “FLARE” position
Examples of Emergency Procedures
It is rare for a diver to overinflate a dry suit, but there are several ways to correct this. Air can be vented from the wrist seal if necessary
Air can also be vented from the neck seal if the exhaust valve is not working properly

51. Dry Suit Emergencies

52. Disconnect Inflator Hose

53. Emergency Procedures Slow leak in inflator valve…
Determine extent of leak, terminate dive.
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54. Emergency Procedures Inflator valve stuck closed…
Stop descent and terminate the dive
Use BCD as needed to control buoyancy
Return to the surface venting expanding air as normal
Exhaust valve stuck closed
Control ascent by allow expanding air to escape or use flare position if air can not be vented.
Use ascent line if available.

55. Emergency Procedures Exhaust valve stuck open…
Determine the extent of leak
Terminate dive
Exercise the valve
Increase valve spring pressure

56. Emergency Procedures Exhaust valve leaking… Determine extent of leak
Terminate dive
Use BCD in controlling buoyancy as needed

57. Emergency Procedures Exhaust valve stuck closed…
Control ascent by pressing exhaust Valve to allow expanding air to escape or use “FLARE” position if air cannot be vented
Use ascent line if available

58. Emergency Procedures Inverted position from air in the feet…
Forward swim-out roll (Tuck & Roll)
Backward swim-out roll
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59. Emergency Procedures Inverted position from air in the feet…
Forward swim-out roll (Tuck & Roll)
Backward swim-out roll
If the diver works in an upside down position, most of the air in the suit will rush to the feet. This is not a problem if the diver has a minimum amount of air inside the suit. Even if there is a lot of air in the suit, the diver can tuck the legs close to the body and roll to an upright position.
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60. Air in legs

61. Emergency Procedures Loss or failure of air supply…
Control ascent rate by venting air from suit as you ascend
Venting air by manually activating exhaust valve may be required
Ditch weight belt to assist with ascent if needed. Stress the importance of flaring while ascending.

62. Emergency Procedures Flooded Suit… Use BCD to control buoyancy
If additional buoyancy is needed, drop weights
Control buoyancy by venting suit or BCD as needed; suit may maintain a large volume of air
Attempt to minimize the effect of leak by positioning it low if possible

63. Emergency Procedures Dropped or lost weight belt or weight system…
Attempt to recover weights
If unable to recover weights, control ascent by exhausting air from suit with valve
If unable to release air from the suit, or ascent is too rapid use the “FLARE” to control ascent

64. Conclusion Thermal and environmental considerations Dry suit selection
Undergarments
Care and maintenance
Emergency procedures