Technical Diver Level 1



The Technical Diver Level 1 (Tech 1) course is structured to prepare divers for the rigors of technical diving and to familiarize them with the use of different breathing and decompression mixtures. Tech 1 training focuses on expanding the fundamental skills learned in the GUE Fundamentals course (or elsewhere), and is designed to cultivate, integrate, and expand the essential skills required for safe technical diving. This will include problem identification and resolution, and building the capacity for progressively more challenging diving. In this class, students will be trained in: a) the use of double tanks/cylinders and in the potential failure problems associated with them; b) the use of Nitrox for accelerated and general decompression strategies; c) the use of Helium to minimize narcosis; and d) the applications of single decompression stage diving with respect to decompression procedures.


The class will focus on enriched air and TriOx (Helium enriched gas), as flexible and beneficial breathing gases for dives in the 40 foot/12 meter to 150 foot/45 meter depth range, and provides an excellent foundation on which divers can build their technical diving experience and prepare for GUE's Technical Diver 2 course (Tech 2).




  1. Must meet GUE General Course Prerequisites as outlined in Section 1.6
  2. Must be a minimum of 18 years of age
  3. Must be GUE Fundamentals qualified
  4. Must have a minimum of 100 dives beyond open water qualification
  5. Must be able to swim a distance of at least 50 feet/15 meters on a breath hold
  6. Must be able to swim at least 400 yards/366 meters in less than 14 minutes without stopping. This test should be conducted in a swimsuit and, where necessary, appropriate thermal protection.




The Tech 1 class is normally conducted over a 5-day period. It involves a minimum of forty (40) hours of instruction, encompassing both classroom and in-water work.


Course Limits


  1. General Training Limits as outlined in Section 1.4
  2. Student to instructor ratio is not to exceed 3:1 during any in-water training
  3. Maximum depth 150 feet (+/- 10 feet)/45 meters (+/- 3 meters)
  4. No overhead environment diving (excepting decompression)


Course Content

The GUE Tech 1 course is normally conducted over a 5-day period, and cumulatively involves a minimum of forty (40) hours of instruction designed to provide a working knowledge of enriched air diving, normoxic and hyperoxic Trimix and decompression mixtures, including history, physics, physiology, tables, and operational considerations.


Course requirements include ten (10) hours of academics and eight (8) dives, six (6) of which will be critical skill dives and two (2) will be experience dives.


Initial dives will be conducted in shallow water to test diver ability and to fill in any deficits in skill levels. The last two (2) dives are to be Trimix dives at depth for experience.


Required Training Materials


  1. Doing it Right: The Fundamentals of Better Diving. Jarrod Jablonski, GUE, 2001, High Springs, Florida.
  2. Getting Clear on the Basics: The Fundamentals of Technical Diving. Jarrod Jablonski, GUE, 2001, High Springs, Florida.


Academic Topics


  1. Physics
  2. Pressure and gas law review
  3. Equations relevant for planning, mixing, and using enriched air
  4. Physiology
  5. Hypoxia
  6. Hyperoxia
  7. Oxygen toxicity
  8. CNS
  9. Pulmonary toxicity
  10. Tracking multilevel, multi-dive, and multi-day exposures
  11. Inert gas narcosis
  12. Inert gas absorption and elimination
  13. Carbon dioxide toxicity
  14. Carbon monoxide toxicity
  15. Hyperthermia
  16. Hypothermia
  17. Decompression illness
  18. Accelerated and general decompression strategies
  19. Decompression practices on air, enriched air, and Oxygen
  20. Generic tables, computers, and custom tables
  21. Introduction to normoxic and hyperoxic Trimix
  22. Advantages over deep air
  23. Equipment considerations (DIR emphasis)
  24. Singles
  25. Doubles
  26. Decompression stage bottles
  27. BC/harness
  28. Regulators, depth gauges, pressure gauges, and hose routing
  29. Manifolds
  30. Surface marker buoys and spools (for deco platforms)
  31. Computers and bottom timers
  32. Exposure suit appropriate for the environment
  33. Dive planning
  34. Operational planning
  35. Support
  36. Teams
  37. Team planning
  38. Gas matching
  39. Oxygen limits
  40. Nitrogen limits
  41. Emergency procedures
  42. Omitted decompression procedures
  43. Miscellaneous issues including limited deco gas, out of gas, team separation, etc.
  44. Procedures
  45. Bottom and deco gas
  46. Normal operations
  47. Procedures for failure, loss, or inadequate supply
  48. Gas mixing
  49. Analyzing and labeling gas supplies
  50. Line following


Land Drills & Topics


  1. Reel and guideline use
  2. Dive team order and protocols
  3. Touch contact
  4. Manifold operation and failures
  5. Use of safety spools and reels
  6. Basic navigation skills
  7. Pre-dive drills




Required Dive Skills & Drills


  1. All skills and drills as outlined in General Diving Skills, Section 1.5.
  2. Procedures for gas failures, including valve manipulation, gas-sharing, and regulator switching as appropriate.
  3. Surface marker buoy deployment.
  4. Buoyancy and trim.
  5. Be able to comfortably demonstrate at least two propulsion techniques appropriate for delicate and/or silty environments.
  6. Use of touch contact for limited and simulated zero visibility situations.
  7. Reel and guideline use.
  8. Demonstrate familiarity with required course equipment.
  9. Gas-sharing scenarios to include gas-sharing for at least 200 feet/60 meters.
  10. Demonstrate the effective deployment of a reserve light in less than 30 seconds.
  11. Demonstrate good buoyancy control skills.
  12. Demonstrate effective valve-management by switching regulators, shutting down a valve in less than 15 seconds and returning the valve to the open position again in less than 15 seconds.
  13. Demonstrate reasonable proficiency with a single decompression bottle.
  14. Demonstrate proficiency with effective decompression techniques, including depth and time management.


Equipment Requirements


Each student should have, and be familiar with, all of the following required equipment.


  1. Tanks/Cylinders: Students are required to use dual tanks/cylinders connected with a dual outlet isolator manifold, which allows the use of two first-stages. All dives must start with a minimum of 80 cubic feet/2250 liters of gas. Divers must also have access to one deco tank/cylinder of 50% Nitrox.
  2. Regulators: Two first-stages, each supplying a single second-stage. One of the second-stages must be on a 7-foot/2-meter hose. One of the first-stages must supply a pressure gauge and provide inflation for a dry suit (where applicable). One first-stage regulator for shallow decompression gas, supplying a single second-stage and pressure gauge.
  3. Backplate System: A rigid and flat platform, of metal construction with minimal padding, held to a diver by one continuous piece of nylon webbing. This webbing should be adjustable through the plate and should use a buckle to secure the system at the waist. A crotch strap attached to the lower end of this platform and looped through the waistband would prevent the system from riding up a diver's back. A knife should be secured to the waist on the left webbing tab. This webbing should support five D-rings; the first should be placed at the left hip, the second should be placed in line with a diver's right collarbone, the third should be placed in line with the diver's left collarbone, the fourth and fifth should be affixed to the crotch strap to use while scootering or towing/stowing gear. The harness below the diver's arms should have small restrictive bands to allow for the placement of reserve light powered by three in-line c-cell batteries (where necessary). The system should retain a minimalist approach with no unnecessary components.
  4. Buoyancy Compensation Device: A diver's buoyancy compensation device should be back-mounted and minimalist in nature. It should come free of extraneous strings, tabs, or other material. There should be no restrictive bands or "bungee" of any sort affixed to the buoyancy cell. In addition, diver lift should not exceed 80lbs. Wing size and shape should be appropriate to the cylinder size(s) employed for training.
  5. At least one depth-measuring device
  6. One timekeeping device
  7. Decompression tables
  8. Mask and fins: Mask should be low volume; fins should be rigid, non-split
  9. At least one cutting device
  10. Wet Notes
  11. One spool with 100 feet/30 meters line per diver
  12. One primary reel per team, with a minimum of 300 feet/90 meters of line
  13. One primary light: A primary light should be minimalist in design; its power source should consist of a rechargeable battery pack residing in a canister powering an external light head via a light cord. Primary lights should produce the equivalent output of 50 watt halogen/10 watt HID lighting or greater.
  14. Two reserve lights: Reserve lights should be non-rechargeable in-line three c-cell battery lights with a minimum of protrusions and a single attachment at its rear. The light should be activated by twisting the front bezel towards the body, deactivated by turning it away from the body.
  15. Exposure suit appropriate for the duration of exposure
  16. At least one surface marker buoy per diver


Note: Prior to the commencement of class, students should consult with a GUE representative to verify equipment requirements. Whether or not a piece of equipment fulfills GUE's equipment requirement remains at the discretion of GUE and its instructor representatives. Participants are responsible for providing all equipment or for making provisions to secure all necessary equipment before the start of the course. In general, it is better for the student to learn while using his or her own equipment. However, students should exercise caution before purchasing new equipment to avoid acquiring substandard equipment. Please contact a GUE representative prior to making any purchases. Information about recommended equipment can be obtained from the equipment considerations section of GUE's web site.

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