1. Surface-Supplied Diving

2. Sources
Joiner, J.T. (ed ) NOAA Diving Manual - Diving for Science and Technology, Fourth Edition. Best Publishing Company, Flagstaff, AZ.
US Department of the Navy US Navy Diving Manual. Revision 4. NAVSEA 0910-LP Naval/Sea Systems Command, 2531 Jefferson Davis Hwy, Arlington, VA.

3. Objectives After completing this training module you will be able to:
List four advantages and four disadvantages of surface-supplied diving compared with scuba
List seven considerations for pre-dive planning of surface-supplied dives
Give three examples of appropriate warning displays for surface-supplied diving activities in high marine traffic areas

4. Objectives After completing this training module you will be able to:
List at least two methods for supplying gas to a surface-supplied diver
Discuss the features of a surface-supplied diver’s harness and the importance of a snap shackle
Provide the important features associated with a bailout bottle

5. Objectives After completing this training module you will be able to:
Describe and list two functions of a manifold block
List the personnel requirements to deploy a surface-supplied diver, and describe the basic responsibilities of each assignment
Explain the importance of checklists

6. Objectives After completing this training module you will be able to:
Explain basic line pull signals from tender to diver and diver to tender
Describe why knowing how to properly ventilate a free-flow and demand style helmet or mask is important to a surface-supplied diver
List five surface-supplied diver emergencies and describe actions to be taken

7. Objectives After completing this training module you will be able to:
Describe procedures used during the ascent and post-dive phase of a surface-supplied dive
List at least four considerations or procedures for umbilical diving from a small boat
State at least two basic supply pressure requirements for both Free Flow and Demand style surface-supplied systems

8. General
One of the diving modes of choice for underwater work that requires the diver to remain submerged for extended periods of time is surface-supplied diving
This module describes some of the techniques and procedures for divers engaged in basic surface-supplied diving

9. History
Prior to the development of surface-supplied diving, underwater work was performed by breath holding and/or work from diving bells

10. History
A critical piece of the groundwork for effective surface-supplied diving was laid in the late 18th century with the development of pumps capable of delivering air under pressure

11. History
Augustus Siebe is credited with the first major breakthrough in surface-supplied diving in 1819 with the invention of a waist-length jacket with a metal helmet sealed to a collar and fed air from the surface by force pump

12. History
Siebe later modified his design incorporating the design for a smoke apparatus developed by John and Charles Deane producing a closed suit design with attached helmet; the direct ancestor of surface-supplied diving systems used by the US Navy until the early 1980s

13. History
No major developments occurred in hard-hat gear until the 20th century with the advent of mixed gases

14. Advantages
Advantages of surface-supplied diving over scuba diving are that it:
Provides a direct physical link to the diver
Permits hard-wire communication between the diver and the surface
Provides an assured, continuous breathing gas supply and thus, longer bottom time
Provides depth control

15. Disadvantages
The disadvantages of surface-supplied diving compared with scuba diving are:
The surface-supplied diver’s mobility and operational range are restricted by the length of the umbilical
The drag weight of the umbilical
The large amount of equipment required to support surface-supplied diving

16. Planning the Dive
The success of any dive depends on pre-dive planning considering dive objectives, required tasks, environmental conditions, hazardous activities at or near the dive site, personnel, equipment, and availability of emergency assistance

17. Planning the Dive
For areas with high marine traffic, an appropriate warning display shall be exhibited near the work site in clear sight of all personnel in the near vicinity
This may include, but not limited to, shapes, lights, flags, or placards
A rigid replica of the international code flag “A” not less than one meter in height should be exhibited during all diving operations

18. Planning the Dive
The dive supervisor should complete a Pre-Dive Environmental Checklist for every surface-supplied dive before deciding on personnel and equipment needs

19. Planning the Dive
Surface conditions have greater effect on the tender and other support personnel than the diver
Accurate depth measurements are necessary for dive planning, as well as information concerning bottom type, tides and currents, marine life, gas requirements, and underwater obstructions

20. Minimum Equipment for Surface-Supplied Diving
Compressor, air banks, or a combination
Diving Control System
A Mask or Helmet
Umbilical
Harness
Stainless Steel Snap Shackle
Bailout Bottle
Manifold Block with Non-return Valve
Exposure Suit (as needed)
Weight (as needed)
Fins or Boots
Dive Knife

21. Gas Supply
A low pressure compressor designed for surface-supplied diving can be used to supply gas to the diver(s)
These compressors must be properly filtered and use special oil designed for breathing air compressors, and must have a volume tank
A bank of cylinders or a combination of bank and compressor can also be used to supply gas to the diver(s)

22. Schematic of a Low-Pressure Compressor-Equipped Gas Supply System

23. Schematic of a Typical High-Pressure Cylinder Bank Gas Supply System

24. Dive Control System
A Dive Control System connects the gas supply to the umbilical
It provides information on the diver’s depth through the pneumofathometer hose; controls the flow of gas to the diver(s); and can include two-way hard wire communication
These systems range is size from portable to built in and range from simple to complex, depending on the application

25. Key Features of Diving Helmets

26. Lightweight Surface-Supplied Masks
Band Mask
AGA Mask
EXO 26 Mask

27. Umbilical Components
The diver’s gas supply hose needs to have a smooth inner bore of at least 3/8 in (9 525 mm) inner diameter
The umbilical can be assembled bundled or twisted with the strength member separate or combined with the communication hose

28. Snap Shackle and Harness
The harness is usually made of flat nylon webbing and is outfitted with stainless steel D-rings that can be used as attachment points
A quick release snap shackle attaches the umbilical to the diver’s harness
This reduces the stress placed on the attachment points of hose to diver
The shackle is designed to remain closed under stress, but can be released under tension if necessary

29. Bailout Bottle
The Bailout Bottle is an emergency air supply in case there is a total failure of the surface-supply system
Or if the divers hose is severed
Or in the event that the umbilical becomes hopelessly entangled and cannot be freed

30. Bailout Bottle
The Bailout Bottle must be of sufficient volume to act as an emergency gas source and may vary in volume capacity depending on the diving depth and working conditions
The Bailout Bottle is equipped with a separate first stage
When attached to a Bailout Bottle, this first stage should be equipped with an over pressure relief valve
This valve is necessary in case the first stage develops IP “creep” that could cause the pressure in the hose from the bottle to the manifold block to increase to the point of bursting

31. Manifold Block
The umbilical is threaded on to the one-way, non-return valve of a manifold block
The manifold block is attached to the divers harness for use with lightweight masks like an AGA or EXO 26, but is part of the helmet assembly of the Superlite or Band Mask

32. Manifold Block
The diver’s mask and bailout bottle are attached to the manifold block
The knob on the manifold block opens and closes a valve
When closed, the valve isolates the bailout bottle and keeps it from being breathed down during the dive

33. Selecting the Dive Team
The number of personnel necessary to conduct surface-supplied operations depends on:
The equipment being used
The environmental conditions
Dive depth and platform type
How the diver(s) will be deployed and retrieved, and the number of divers being deployed

34. Selecting the Dive Team
Deployment of one surface-supplied diver could require as many as six people, depending on the conditions and the complexity of the dive:
Working diver
Dive tender
Dive supervisor
Standby diver
Standby tender
Timekeeper

35. Selecting the Dive Team
For less complex dives the number needed to deploy a single diver could be reduced to three people with individuals performing multiple tasks:
Working diver
Supervisor/Timekeeper/Standby tender
Tender/Standby diver

36. Selecting the Dive Team
The diving supervisor is responsible for planning, organizing, and managing all of the dive operations; to include determining equipment requirements, inspecting equipment pre and post-dive, selecting team members and assigning tasks, conducting briefings and debriefings, monitors the progress of the dive, coordinates emergency response, checks dive logs and prepares reports on the dive
The diving supervisor must remain at the dive location at all times

37. Selecting the Dive Team
The diver(s) must be qualified and trained in the equipment and techniques of the dive, including both line pull and voice signals
The diver must keep surface personnel informed of the progress of the dive, bottom conditions, and real or potential problems
Every diver is responsible for ensuring that their dive gear is complete, in good repair, and ready for use

38. Selecting the Dive Team
The standby diver must be as well-trained and qualified as the diver being supported
A stand by is required for all surface-supplied operations, regardless of size
It is the responsibility of the standby diver to be ready to provide emergency or backup support whenever the diver is in the water

39. Selecting the Dive Team
The tender is either a qualified surface-supplied diver or has received specialized training required to be a competent tender
Every surface-supplied diver must have at least one tender in control of the umbilical at all times

40. Selecting the Dive Team
The tender:
Checks the diver’s equipment
Checks the gas supply
Helps the diver get dressed
Helps the diver to/from the entry/exit point
Tends the diver’s umbilical to ensure no excess slack or tension is on the line
Maintains communication with the diver and keeps the diving supervisor informed of the diver’s progress

41. Selecting the Dive Team
Long or complex dives may require a standby tender to assist or replace the primary tender
This individual must also be fully qualified and should attend all briefings and be kept aware of what is going on with the dive

42. Selecting the Dive Team
The time keeper’s responsibilities include keeping an accurate record of dive times, depths, and noting all of the important details of the dive
During dives involving limited number of dive team members, the tender or dive supervisor may act as time keeper

43. Preparing for the Dive
In addition to preparing equipment, diver, and personnel for the dive; a pre-dive checklist should be employed to ensure the diver is properly dressed prior to deployment and to identify and correct potential problems

44. The Importance of Checklists
It is common practice to use checklists throughout surface-supplied diving operations (pre, during, and post-dive) to standardize procedures and minimize errors

45. The Importance of Checklists
These will be gone over in detail during the hands on portion of your surface-supplied diver training, and may vary from the examples presented here

46. Preparing for the Dive A minimal pre-dive checklist consists of:
Check to ensure the suit is donned properly
Check diver’s safety harness and emergency bailout system for fit and accessibility
Check diver’s weighting
Check and log emergency bailout system mixture and cylinder pressure
Check primary and secondary gas bank and supply pressure
Ensure gas flow to mask or helmet
Check function of emergency gas system
Check proper function of helmet or mask components
Perform communications check

47. Preparing for the Dive
Once deployed, the diver should stop just under the surface and:
Adjust the demand regulator air supply and perform a “bubble check” for major leaks
Recheck the function of the emergency supply valve and free flow valve (the valve isolating the bailout cylinder must be closed until needed to avoid breathing the bailout gas supply down during the dive)
Repeat communications check

48. Tendering the Surface-Supplied Diver
Contact between the tender and the diver must be maintained throughout the dive
This contact starts with the tender placing a hand on the fully dressed diver as the diver moves to the entry point
The tender maintains physical control of the diver as the diver enters or leaves the water

49. Tendering the Surface-Supplied Diver
As the diver descends, the tender pays out slack according to the decent rate, but never faster than is needed by the diver
The tender should always be able to feel the diver
Once on the bottom the tender and the diver work as a team
The tender should only supply enough slack in the umbilical so as not to hinder the diver’s work (usually about 2-3 ft)

50. Tendering the Surface-Supplied Diver
If voice communication is lost the tender and diver must be able to communicate using line-pull signals
All communications between the diver and the tender should be passed on to the dive supervisor
If the diver fails to respond after several communication attempts, the situation should be treated as an emergency

51. Line Pull Signals
A line pull signal is one pull or a series of sharp, distinct pulls on the umbilical which are strong enough to be felt by the diver or tender
All slack must be taken out of the line before the signal is given

52. Line Pull Signals From the tender to the diver:
1 Pull – “Are you OK?” When diver is descending, 1 pull means “Stop”
2 Pulls – “Going Down”
On ascent, 2 pulls means “You have come up too far; go down until we stop you ”
3 Pulls – “Stand by to come up”
4 Pulls – “Come up”

53. Line Pull Signals From the diver to the tender: 1 Pull – “I am OK”
When descending, 1 pull means “Stop” or “I am on the bottom”
2 Pulls – “Lower” or “Give me slack”
3 Pulls – “Take up my slack”
4 Pulls – “Haul me up”

54. Line Pull Signals
Most line pull signals are repeated back by the person receiving them to communicate the signal has been received and understood
Additional line pull signals will be covered during the hands on portion of surface-supplied training

55. The Dive
surface-supplied divers enter the water using a “stage”, by jumping, or by climbing ladders
The diver(s) are relying on the tender(s) to maintain sufficient slack on the umbilical

56. The Dive The following actions should be taken, as appropriate:
The diver should check buoyancy (being weighted neutrally or negatively is dependent on the dive’s objectives)
The supervisor should verify that the gas supply and communications are functioning properly, and that the diver’s equipment is functioning satisfactorily
The tender checks for leaks in gas supply fittings or suit and looks for air bubbles
The supervisor should give the diver permission to descend

57. The Dive Actions to be taken, continued:
The diver should descend down a descent or “shot” line, equalizing pressure as needed
Upon reaching the bottom the diver informs the tender of the diver’s status and ensures the umbilical is not fouled around the descent line
To aid in relocating the stage, the diver may choose to employ a travel line to the work area or may pass the umbilical through the bail of the stage or bell
The diver should proceed to slowly to conserve energy and it is advisable for the diver to carry one turn of the umbilical in hand to allow for unexpected pulls on the hose

58. The Dive Actions to be taken, continued:
The diver should pass over, not under, wreckage and obstructions
If moving against current, it may be necessary to crawl
If the diver is required to enter wreckage, tunnels, etc., a second diver must be one the bottom to tend the umbilical at the entrance to the confined space
The diver(s) should be notified a few minutes in advance of termination of the dive so that tasks can be completed and preparations made for ascent

59. Pneumofathometer
An open ended pneumofathometer hose is used to check the diver’s depth
The Dive Control System operator briefly opens a valve on the control panel causing the gas at the diver’s end of the pneumo hose to equalize pressure with the surrounding water
The diver’s depth is displayed on a gauge on the control panel

60. Pneumofathometer
The diver’s depth should be checked periodically during the dive
The valve controlling gas to the pneumo hose need not be opened during ascent, the gas in the hose bubbles out as the diver ascends producing an accurate depth reading on the control panel gauge

61. Ventilation
If the diver experiences rapid breathing, panting or shortness of breath, abnormal perspiration, or an unusual sensation of warmth, dizziness, blurred vision, or if the helmet/mask viewport becomes foggy, there is probably an excess of carbon dioxide in the headgear

62. Ventilation
To eliminate excess CO2 in a free-flow helmet or mask the diver must ventilate the helmet or mask by increasing the flow for a minimum of seconds
CO2 retention is not as common in demand valve helmets and masks as long as the diver breaths normally; has the flow valve adjusted properly; or does not over work the system with too high a work rate
To ventilate a demand valve helmet or mask, the free-flow or demand regulator purge valve can be used for five to ten seconds

63. Diver Emergencies: Fouling
A surface-supplied diver’s umbilical may become fouled for any number of reasons
Divers who are fouled should:
Remain calm and control breathing
Think clearly
Describe the situation to topside
Determine the cause of fouling and, if possible, clear themselves
Be careful to avoid cutting portions of the umbilical assembly when using a knife or other cutting implement
If efforts to clear themselves are unsuccessful, divers should call for the standby diver then wait calmly for their arrival

64. Diver Emergencies: Blowup
Blowup is the uncontrolled ascent of a diver from depth
Blowup can result when a drysuit becomes over inflated; the diver loses control of their buoyancy; as a result of entanglement with equipment moving toward the surface; when excess drag on the umbilical by current sweep the diver toward the surface; etc.
Blowup can cause:
Arterial gas embolism
Decompression sickness
Missed decompression stops
Physical injury (striking objects in the water column or the diving platform)

65. Diver Emergencies: Blowup
After surfacing, blowup victims should not be allowed to resume diving
If a diver who has experienced a blowup appears to have no ill effects and is still within the no decompression limits of the dive tables used, s/he should return to a depth of 10 feet (3 m) and decompress for the amount of time normally required to ascend from the diver’s working depth
Upon surfacing the diver should be observed for at least an hour for signs of decompression sickness or other injuries

66. Diver Emergencies: Blowup
Blowup victims who are close to no decompression limits, or requiring decompression, may be able to follow surface decompression procedures, or may require chamber treatment
Appropriate emergency response actions should be initiated

67. Diver Emergencies: Loss of Primary Air Supply
Loss of the primary gas supply is possible but unlikely
If it happens the person operating the gas control system should immediately switch to the secondary gas source and notify the diving supervisor
As the problem is being investigated, perpetrations to recall the diver should be initiated:
The tender is directed to remove slack from the umbilical and the diver is directed to assure the umbilical is clear in anticipation of the diving supervisor calling for the dive to be aborted

68. Diver Emergencies: Loss of Primary Air Supply
The procedure for a diver reporting low gas flow or the helmet or mask breathing hard is to have the operator to check the supply console;
If supply gas pressure is adequate, the problem may be along the umbilical
The diver should switch to the bailout; if gas flow improves the diver should check to insure the umbilical is clear
It may become necessary for the supervisor to call an abort to the dive or to deploy a standby diver with a spare umbilical and tools to switch out the fouled umbilical
Never continue a dive with only one gas source

69. Diver Emergencies: Loss of Communication or Contact
If hard-wire communication is lost, the tender should immediately attempt to communicate with the diver by line-pull signals
If the diver responds, and depending on diving conditions and the arrangements made during dive planning, the dive may either be terminated or continued using line-pull signals

70. Diver Emergencies: Loss of Communication or Contact
If the diver does not respond, the tender should take up additional strain on the umbilical and repeat the line-pull signal
If the diver continues to be unresponsive the standby diver should be deployed and appropriate actions taken depending of the situation

71. Diver Emergencies: Falling
Falling is a serious hazard for divers using free-flow helmets or masks
The principle danger is the sudden increase in ambient pressure resulting in a squeeze if the diver cannot immediately compensate by adding gas
The tender must always be alert to the possibility of a fall and should take strain on the umbilical to stop the diver’s descent should a fall occur

72. Ascent
The diving supervisor will order the diver back to the stage/bell or descent line when the diver’s bottom time has expired or the task has been completed

73. Ascent During the ascent the following procedures should be used:
The tender should exert a slight strain on the umbilical assembly
The tender should exert a slow, steady pull, as directed by the diving supervisor
The diving supervisor starts timing the ascent as soon as the diver indicates leaving the bottom
The consol operator monitors the divers depth via the pneumofathometer hose and relays information to the diving supervisor

74. Ascent Ascent procedures continued:
If diving a drysuit, the diver will bleed gas as necessary to avoid a blowup
Generally, the supervisor will inform the diver well in advance of decompression requirements
When the diver surfaces, the tender and topside personnel help the diver to the dressing bench where the helmet or mask is removed, followed by the remaining equipment

75. Post-dive Procedures
After all equipment has been removed and been checked by the diving supervisor, the diver should remain in the general vicinity for at least 30 minutes
If diving operations are concluded:
Clean the helmet or mask and emergency gas system; rinse thoroughly, and blow down with air
Secure the gas supply to the helmet or mask; disconnect and cap, or bag exposed fittings
Clean and rinse all diving equipment
Blow down the diver’s umbilical, disconnect, and stow
Ensure the dive control system has been properly secured
Post-dive maintenance includes cleaning the interior of the mask or helmet with a disinfecting solution in accordance with manufacturer recommendations

76. Umbilical Diving from Small Boats
Although most surface-supplied diving is conducted from large vessels or fixed platforms, the umbilical system can be adapted to small boat operations
A minimum two-point moor is recommended to help prevent the craft entangling the diver
High pressure cylinders attached to the gas control system are more commonly used than compressor systems and volume tanks for small boat surface-supplied operations

77. Umbilical Diving from Small Boats
Generally, it is wise to limit diving depths to less than 100 ft (31 m) when working from a small boat
The dive team for a surface-supplied dive from a small boat consists of a diving supervisor, a diver, tender and standby diver
Sufficient cross-training of personnel to allow for emergency/contingency situations is a must
The standby diver can be equipped for a surface-supplied dive or can be equipped with scuba; s/he should be capable of donning scuba and entering the water in less than one minute
A standby diver using scuba should be fitted with a quick-release lifeline, or hard-wire communication line (readily releasable in the event of entanglement)

78. Supply Pressure Requirements
Free-Flow Systems
Many factors can influence gas flow when using a free-flow mask or helmet; length and inside diameter of umbilical, number of umbilical couplings, supply valve restrictions, and supply pressure
When diving to depths up to 120 fsw (37 msw), it is recommended that umbilical pressure be at least 50 psi over ambient pressure
When diving to depths in excess of 120 fsw (37 msw), it is recommended that the supply pressure be at least 100 psi over ambient pressure

79. Supply Pressure Requirements
To calculate supply pressure for free-flow systems for depths less than 120 fsw:
Ps = 0.445D + 65
Where:
Ps = supply pressure in psig
D = depth in fsw
65 = absolute hose pressure (50 psi +14.7)

80. Supply Pressure Requirements
To calculate supply pressure for free-flow systems for depths greater than 120 fsw:
Ps = 0.445D + 115
Where:
Ps = supply pressure in psig
D = depth in fsw
115 = absolute hose pressure (100 psi +14.7)

81. Supply Pressure Requirements
Demand Systems
Demand-mode diving generally requires higher supply pressures, but the overall gas usage is less than that of free-flow diving
The need for great quantities of gas to ensure low levels of CO2 is eliminated due to the use of oral-nasal masks or very small oral cavities
The actual pressure needed to allow a helmet or mask to work efficiently is dictated by the manufacturer

82. Supply Pressure Requirements
To calculate supply pressure for demand systems:
Ps = 0.445D + MRPOA
Where:
Ps = supply pressure in psig
D = depth in fsw
MRPOA = manufacturer’s recommended pressure over ambient

83. Supply Pressure Requirements
It must be remembered when computing the flow requirements, the actual flow will be influenced by mechanical restrictions in the system
For example; the flow at the diver’s end of a single 300 ft umbilical would be greater than the flow through two 150 ft umbilicals coupled together
Some manufacturers will provide guidelines for surface-supply control consoles and umbilical configurations

84. Study Questions
Use the following study questions to review some of the information presented in this self study module
When you are finished you can print out your study questions results

85. Surface Supplied