The TDI Advanced Trimix Course provides the training required to competently and safely utilize breathing gases containing helium for dives that require staged decompression, utilizing Nitrox and / or oxygen mixtures during decompression to a maximum depth of one hundred (100) metres. The objective of this course is to train divers in the benefits, hazards and proper procedures of utilizing custom oxygen / helium / nitrogen mixtures as breathing gases.
Qualifications of Graduates:
Upon successful completion of this course, graduates may engage in technical diving activities utilizing custom Trimix mixtures without direct supervision as long as:
- The diving activities approximate those of training.
- The area of activities approximates those of training.
- Environmental conditions approximate those of training.
Student Pre-Requisites:
- Be a minimum age of eighteen (18).
- Have a minimum certification as an Extended Range Diver or Entry Level Trimix Diver (or equivalent).
- Show proof a minimum of one hundred (100) logged dives with 25 deeper than one hundred (100) feet/ thirty (30) meters.
- Prior logged experience w/ double cylinders and any other unfamiliar equipment. I.E. Dry suit
Course Structure and Duration:
- Four (4) dives with a minimum accumulated bottom time of one hundred (100) minutes
- At least two (2) dives should be deeper than fifty five (55) msw / one hundred eighty (180) fsw.
Required Equipment:
- Suit Inflation Cylinder
- Buoyancy Compensator(s) adequate for equipment configuration.
- Redundant Depth and Timing Devices. Air decompression computers allowed for use as depth and timing devices.
- Redundant Light System if required by site.
- Ascent Reel with Lift Bag/Surface Marker Buoy.Adequate for maximum planned depth. Minimum of twenty three (23) kg / fifty (50) lb. lift bag (a dump valve highly recommended).
- Exposure suit adequate for the open water environment.
- Line Cutting Device.
- Underwater Slate (for decompression / contingency tables).
Regulators:
- Primary and primary redundant required on all bottom mix cylinder(s).
- Submersible pressure gauges are required on all primary bottom mix cylinders.
- A contingency use long hose second stage should be designated and appropriately rigged to facilitate air sharing at depth if necessary.
- It is strongly recommended that all four (4) required regulators be DIN or all four (4) regulators be yoke.
Bottom Mix Cylinder(s)
- Cylinder volume appropriate for planned dive and student gas consumption.
- Dual outlet valve, double manifold or independent doubles.
- Labeled in accordance with TDI Standards.
Travel Mix Cylinder(s)
- Cylinder volume appropriate for planned dive and student gas consumption.
- Labeled in accordance with TDI Standards.
Decompression Mix Cylinder(s):
- Cylinder volume appropriate for planned dive and student gas consumption.
- Labeled in accordance with TDI Standards.
You will be expected to:
- Be competent in skills required to graduate from any prerequisite TDI course (or equivalent)
- Properly analyze all gas mixes to be used.
- Calculate and mark MOD of each mix appropriately.
- Demonstrate adequate pre-dive planning (limits based on team experience, gas consumption of individuals and of team as a whole, oxygen depth and time, inert gas depth and time, environment, contingency and so on).
- Properly execute a planned (dives within all predetermined limits.
- Satisfactorily complete TDI written exam.
- Demonstrate mature and responsible judgement concerning dive planning and execution.
- Maintain a high level of awareness and respect for environment in which all diving and dive preparation is conducted.
- Log all dives.
Required Skill Performance And Graduation Requirements:
Land or field skills:
- Demonstrate familiarity with basic and intermediate hand signals.
- Select and prepare of equipment suitable for soft overhead environment with long decompression obligations.
- Conduct team oriented drills for SMB deployment and gas switching procedure.
- Drills for buddy rescue
Pre-dive skills:
- Use START* before every dive
- Stress analysis and mitigation
Skills during dive:
- Demonstrate buoyancy control (ability to hover at fixed position in water column without moving hands or feet).
- Show good awareness of buddy and other team members through communications, proximity and team oriented dive practices.
- Demonstrate competence managing three stage cylinders including drop and recovery while maintaining position in the water column.
- Ability to manage multiple failures in adverse conditions.
- Complete a horizontal breath hold swim at depth for 20 meters with mask off or blacked out.
- Deploy lift bag while sharing air on buddy’s long hose.
In order to complete this course, students must:
- Satisfactorily complete the TDI Trimix Course written examination.
- Complete all open water requirements safely and efficiently.
- Demonstrate mature, sound judgment concerning dive planning and execution.
*) START is Sdril (OOA drill and bubble check), Team checks, Air (gas matching), Route (entry/exit and planned path underwater, Tables (depth, duration, waypoints and schedule).