Surface-Supplied Diving

1. Surface-Supplied Diving

2. Sources • Joiner, J.T. (ed ). 2001. NOAA Diving Manual - Diving for Science and Technology, Fourth Edition. Best Publishing Company, Flagstaff, AZ. • US Department of the Navy. 1999. US Navy Diving Manual. Revision 4. NAVSEA 0910-LP-708-8000. 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. 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 Minimum Equipment for Surface-Supplied Diving

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