Purpose

The UTD mCCR Rebreather Diver 3 course is designed to further educate individuals in the use of MC rebreather technology as it applies to trimix depth ranges and decompression schedules that require multi bottle decompression bailout. This course will make divers proficient in the use of fully-closed circuit technologies while diving Trimix, and allows divers to gain practical experience with their rebreather while learning to apply its use to their extended range trimix activities. Emphasis here is placed on advanced concepts such as rebreather theory, gas mixture/management, control of exposures to oxygen, and the fatal funnel (hyperoxia, hypoxia and hypercapnia.) However, the course is heavily experience based and deals most specifically with the practical implications of closed circuit rebreather diving.

Prerequisites

• Must be a minimum age of 21 years of age.
• UTD mCCR Rebreather 2 (equivalent not allowed) and UTD Trimix or equivalent.
• Must have completed the online UTD mCCR rebreather class and test
• Must have at least 400 scuba dives beyond open water qualification. Of which 100 must have been in doubles, with at least 200 involving a mCCR.
• Must have 200 hours on a fully closed rebreather.
• Must be able to swim a distance of at least 60 feet/18 meters on a breath hold.
• Must be able to swim at least 400 yards/365 meters in less than 14 minutes without stopping.
• All participants must be able to tow a diver in full equipment, in the environment they will be diving in, for 10 minutes.
• All participants must demonstrate the rescue of a diver simulating oxygen toxicity or unconsciousness

Course Limits

• Student to Instructor ratio is not to exceed 4:1 during any in water training
• Maximum depth 250 ft/75 m
• No overhead environment diving

Course Content

The UTD mCCR Rebreather Diver 3 course is normally conducted over a 5-day period, and cumulatively involves a minimum of 40 hours of instruction designed to ensure a working knowledge of rebreather diving, including failure situations, and life-saving solutions. Topics also include a review of decompression diving, oxygen tolerance, and other operational considerations central to the exploration of extended range environments with a rebreather.

Course requirements include a minimum of ten hours of academic review and at least ten open water dives, of which four will be critical skills dives and six will be conducted in excess of 150 feet/45 meters and will include multi stage decompression. At least two dives will be conducted at or below 200 feet/60 meters utilizing Trimix and multi bailout decompression bottles.
Online Classroom Courses & Text

1. Online Courses – mCCR Rebreather
2. mCCR Rebreather Planning and Pre Dive Checklists and Sheets
3. mCCR DVD is recommended

Academic Topics

A. Purpose
B. History
C. Types of Rebreather
D. Common Components of a Rebreather and how they function
E. Inherent Risks of Rebreathers
F. Introduction to the mCCR Rebreather
G. mCCR Rebreather Alarms and Warnings
H. The Physics Behind a mCCR Rebreather
I. Configuration
J. mCCR UTD/DIR Rebreather Physical Design
K. Problem Recognition & Management
L. The Importance of Instinctive Physiological Monitoring
M. Pre-Dive Planning
N. Diving the mCCR Rebreather
O. Post Dive Procedure
P. Perceived vs. True Work Of Breathing In Rebreather
Q. Need for continuing Education and skill reinforcement

Land Drills and Topics

• Pre Dive Setup and Calibration
• mCCR Rebreather Function, Failures, Gas sharing, Flow checks
• Manifold Failures
• Gas-addition (O2/Diluent) Failures
• Air-sharing
• Water Clearing
• Loop Recoveries
• Rescues
• Multiple bailout/decompression bottle management and deployment

Required Dive Skills & Drills

• Access and review diving limitations.
• Understand and develop skills to master the priority assignment philosophy
• Procedures for gas failures; including valve manipulation, air-sharing, and regulator switching as appropriate.
• Demonstrate the ability to deploy a lift bag/surface marker buoy
• Demonstrate the capacity to recognize, evaluate and correct floods, and then discharge excess water.
• Demonstrate the effective diagnosis and correct response to simulated rebreather problems.
• Air-sharing scenarios for at least 200 feet/60 meters.
• Demonstrate effective valve-management by switching regulators, shutting down a valve and returning the valve to the open position.
• Demonstrate a clean and efficient removal of stage and/or decompression bottles while hovering horizontal.
• Demonstrate the ability to recognize the presence of elevated CO2 levels.
• Demonstrate the ability to comfortably switch gases using the gas addition manifold while maintaining good trim and neutral buoyancy.
• Demonstrate proficiency in safe diving procedures, including assembly, vacuum and pressure test, pre-dive preparations, pre dive vacuum test, flow check, in-water activity and post dive assessment and break down.
• Demonstrate the ability to safely switch between Closed Circuit and Open Circuit
• Efficiently and comfortably demonstrate how to donate air to an out of air diver in multiple air sharing episodes from Closed Circuit with one or more experiences to include a distance of at least 30 feet (9 meters).
• Be able to comfortably demonstrate use, manipulation and failures of the gas addition system.
• Demonstrate awareness of the working of a team member’s Rebreather and a concern for safety, responding quickly to visual cues and diver partner needs if the RB should fail.
• Demonstrate proficiency with dive rescue techniques, including effective management of the following situations: assisting a panic stricken diver, a convulsing diver and an unconscious diver.
• Demonstrate reasonable proficiency with use of the Rebreather during ascents, descents and diving..

Equipment Requirements

• Rebreather: mCCR mCCR Fully-closed circuit rebreather
• Tanks/Cylinders: Students are required to use dual tanks/cylinders connected with a dual outlet isolator manifold, which allows for the use of two first stages. The double cylinders must be accessible by both the rebreather and the open circuit regulators. A minimum of two bailout/decompression bottles with first stages, second stages, and rebreather supply hoses – one oxygen and one Nitrox 50 bottle. All dives must start with a minimum of 40cf/1120 liters of gas in backgas/bailout.
• 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).
• Two bailout/decompression bottles (Nitrox 50 and Oxygen) with appropriate regulators.
• Buoyancy Compensator: Back-mounted wing, mated with a harness and back plate
• At least one depth-measuring device
• One timekeeping device
• Mask and fins: fins must be of non-split variety
• At least one cutting device
• Underwater slate or Wet Notes
• One reel/spool, with 75 feet/22 meters of line, per diver
• One primary reel per team, with a minimum of 300 feet/90 meters of line
• Two lights: one primary and one secondary
• Exposure suit appropriate for the duration of exposure
• At least one surface marker buoy per diver