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Fathom Mk III CCR User Manual

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Mk III CCR User Manual

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  • Page 1 Mk III CCR User Manual...

  • Page 2: Table Of Contents

    Loop Hoses T-Pieces Scrubber Radial vs Axial Scrubber Capacity Scrubber Canister Head Oxygen Sensors Gas Injection Oxygen Addition Adjustable CMF Oxygen First Stage IP Adjustment Submersible Pressure Gauge (SPG) Needle Valve Adjustment Oxygen MAV FATHOM Mk III CCR User Manual...
  • Page 3 Preparing for a Dive Periodic Checklist Oxygen Flow Oxygen Sensors Build Checklist Consumables Assembly Pressure Tests Calibration On-Site Checklist Pre-dive Checklist Disassembly and Cleaning Quick Cleaning Complete Disassembly and Cleaning Loop Head Canister MAVs Storage FATHOM Mk III CCR User Manual...
  • Page 4 Replacement Loop Hoses Hose Clamps DSV/BOV Lubrication Mushroom Valve Replacement BOV Second Stage Service Spares Kit Factory Service Technical Specifications Appendix Mk III CCR O-ring Kit Build Checklist Periodic Checklist On-site and Pre-dive Checklists FATHOM Mk III CCR User Manual...

  • Page 5: Introduction

    Introduction Welcome to the FATHOM Mk III CCR, a closed circuit rebreather designed for the most demanding diving environments. The FATHOM Mk III CCR combines high quality materials, precision machining, and simple intuitive operation. The FATHOM Mk III CCR is the measure of exploration.

  • Page 6: Closed Circuit Rebreather

    Another broad categorization is how the CCR is worn on the diver. The CCR can be backmounted, sidemounted, chestmounted, or a hybrid. The FATHOM Mk III CCR is a backmounted mCCR. CCRs have advantages and disadvantages when compared to open-circuit diving. The advantages include significant gas efficiency, which results in practical advantages such as increased duration, reduced logistical requirements, and cost savings.

  • Page 7: Inherent Risks

    This can occur due to a system failure or user error. In the case of a Fathom CCR, failure to open the oxygen cylinder or needle valve, or a complete loss of oxygen supply, could lead to hypoxia if not noticed and corrected by the diver.

  • Page 8: Components

    The FATHOM Mk III CCR offers several configurations as well as periodic updates. As such, it is possible that not all components listed in this manual are installed on your unit or may appear slightly different than yours.

  • Page 9: Breathing Loop

    Components Breathing Loop The FATHOM Mk III CCR’s breathing loop consists of counterlungs, bail-out valve (BOV), loop hoses, and T-pieces. These components direct the flow of gas around the loop, allowing the scrubber material to absorb carbon dioxide and the sensors to measure and report the oxygen content to the monitoring devices.

  • Page 10: Dsv

    The FATHOM DSV utilizes a barrel valve for simple one-handed operation to dive (open) or surface (close) the loop. When the DSV is in the surface (closed) position, with the handle down, the loop is closed off from the environment.

  • Page 11: Loop Hoses 1

    Components Loop Hoses The FATHOM Mk III CCR utilizes flexible stretch hoses in front and more traditional stiff hoses in the rear. The front stretch hoses allow divers to turn their head more easily while the rear hoses offer greater durability in case they come in contact with the ceiling.

  • Page 12: Scrubber

    Because of this, an axial scrubber is limited in its size (and duration) as work of breathing increases dramatically as scrubber bed length is increased. FATHOM Mk III CCR User Manual...

  • Page 13: Scrubber Capacity

    Two sizes of radial scrubber are Constructed of fiber-reinforced thermoset epoxy available for the FATHOM Mk III CCR, 2.3 kg/5 lb matrix, Black Amalgon features an ultra-smooth and 4 kg/8.8 lbs. The 2.3 kg/5 lb scrubber basket inner surface.

  • Page 14: Head

    PO monitoring devices, and connects the loop hoses to the scrubber canister. The FATHOM Mk III CCR’s head was designed with simplicity, minimal static loop volume, and the smallest possible footprint as primary objectives. It is machined out of a single piece of Delrin with...

  • Page 15: Oxygen Sensors

    12 months. throughout each dive. To check the cells for current limiting, the diver can The FATHOM Mk III CCR head contains three perform an oxygen flush on a dive at or around Analytical Industries PSR-1 1-39-FDS oxygen sensors...

  • Page 16: Gas Injection

    2 ata to ensure all sensors are linear within the expected operating range. This process is part of the Fathom CCR Periodic Checklist and should be completed at least every three months or whenever the diver hasn’t been in the water for more than a month.

  • Page 17: Oxygen Addition

    However, unlike needle valve systems of the past, the FATHOM Mk III CCR employs a needle valve with a non depth-compensated, or absolute pressure, first stage, creating an adjustable, on-the-fly CMF DECREASE system.

  • Page 18: Oxygen First Stage Ip Adjustment

    (IP) has a practical depth limit of 81 msw/260 fsw. you intend to make regularly. When deciding on The FATHOM Mk III CCR addresses the depth an IP, use the maximum depth you will realistically limit by modifying the oxygen first-stage with a...
  • Page 19 Components Adjustment: Adjusting the IP on your FATHOM Mk III CCR is fairly straight forward. Equipment you will need includes a spanner wrench to remove the environmental endcap, a 6 mm allen wrench, and an IP gauge. Remove the retaining ring with a spanner wrench and remove the Delrin blanking plug under it.

  • Page 20: Submersible Pressure Gauge (Spg)

    A leaking APRV may indicate a high pressure seat failure in the first stage or it may just need to be adjusted. Either issue should be addressed prior to use. FATHOM Mk III CCR User Manual...

  • Page 21: Needle Valve Adjustment

    Use the handle to adjust the needle valve until a flow rate between 0 and 0. 1 lpm is achieved. Push the handle down until it stops and re-tighten the set screw. FATHOM Mk III CCR User Manual...

  • Page 22: Oxygen Mav

    BC inflator cartridge that can be easily rebuilt or replaced. NEEDLE VALVE HANDLE BYPASS NEEDLE MANUAL ADD VALVE BUTTON MANUAL MANUAL ADD VALVE ADD VALVE MANUAL ADD BUTTON OXYGEN MAV DILUENT MAV FATHOM Mk III CCR User Manual...

  • Page 23: Displays

    (AI). without a backup would force a diver to bail out The FATHOM Mk III CCR utilizes the Shearwater to open circuit. As such, all FATHOM CCRs have Petrel 3 Analog Cable Gland (ACG) model in redundant PO monitoring.

  • Page 24: Heads Up Display

                 that provides the diver with essential PO information. The FATHOM HUD utilizes a modified            Smithers Code, which is a system of flashing lights that communicates PO information to the diver.

  • Page 25: Gas Cylinders

    Gas Cylinders HUD Calibration Calibration is the process on the rebreather’s The FATHOM Mk III CCR is designed to allow monitoring devices (handset or HUD) used to align the diver flexibility in cylinder size and configuration. the oxygen sensors’ output in millivolts to a known While there are several options available to divers, partial pressure of oxygen.

  • Page 26: Preparing For A Dive

    Preparing for a Dive Great care must be taken when preparing your FATHOM Mk III CCR for a dive to ensure proper operation. For this reason, the FATHOM Mk III Build Checklist should be used anytime the unit is being prepared for diving. This section of the manual will explain each step of the assembly process as outlined in the build checklist.

  • Page 27: Periodic Checklist

    Preparing for a Dive Periodic Checklist Oxygen Sensors With sensors installed in head and handset The FATHOM Mk III CCR has a Periodic Checklist connected, check and record air mV for all three and a Build Checklist. The Periodic Checklist should sensors in the first column of table.

  • Page 28: Build Checklist

    The assembly process should begin by inspecting all of the consumables to ensure there is adequate capacity remaining. Consumables, which become depleted during normal use and must eventually be replaced, include: oxygen, diluent, oxygen sensors, batteries, and CO2 absorbent. FATHOM Mk III CCR User Manual...
  • Page 29 Fill pressures should also be double checked immediately before each dive. FATHOM Mk III CCR User Manual...
  • Page 30 (or other object, such as a golf ball) to avoid sorb spilling inside. Fill the scrubber full with Sofnolime 797 or Intersorb 812 CO2 absorbent. FATHOM Mk III CCR User Manual...
  • Page 31 CO2 bypass. FATHOM Mk III CCR User Manual...
  • Page 32 Do not rely on the bar graph. Turn on the HUD and record the battery voltage. It is worth replacing the battery when it gets to 3.0V or below, indicated by orange or red flashes at startup. FATHOM Mk III CCR User Manual...
  • Page 33 12 months of service OR past its expiration date. If either condition applies to any sensor, it must be replaced prior to use. Record air mV of all three sensors prior to assembly. FATHOM Mk III CCR User Manual...

  • Page 34: Assembly

    If you are using the 5lb/2.3kg scrubber, you will need to insert the appropriate spacer into the bottom of the canister. If using the 8.8lb/4kg scrubber, no spacer is needed. Insert the scrubber into the canister. FATHOM Mk III CCR User Manual...
  • Page 35 Once the head is seated properly in the canister, insert the line-lock. FATHOM Mk III CCR User Manual...
  • Page 36 Fix the top of the counterlungs to the shoulder Check to make sure the bracket and locking pin harness by folding the velcro on the counterlungs have seated properly and the cylinders are secure. around the harness and fastening it securely. FATHOM Mk III CCR User Manual...
  • Page 37 Preparing for a Dive Flow Test BOV or DSV To ensure that the gas is properly directed through the FATHOM Mk III CCR, special attention needs to be given to the mushroom valves located in the mouthpiece. They must be checked (visually and functionally) prior to assembling the breathing loop.
  • Page 38 Install oxygen and inflation first stage regulators on respective onboard cylinders and route hoses appropriately. Connect oxygen hose to oxygen MAV and inflation hose to BC inflator (Cave rig). Install regs on diluent/bailout cylinders. FATHOM Mk III CCR User Manual...

  • Page 39: Pressure Tests

    Wait three to five minutes and visibly inspect that the loop hoses have not relaxed, which would indicate a leak in the loop. Pneumatics Checks Verify all high pressure systems (MAVs, BOV, wing, drysuit) are functioning correctly. FATHOM Mk III CCR User Manual...

  • Page 40: Calibration

    Preparing for a Dive Calibration While the FATHOM Mk III CCR handset and HUD do not need to be re-calibrated each day, the calibration must be checked to ensure that all sensors are performing correctly. If any sensors’ millivolt output has deviated significantly (+/-10%) since the last calibration, or appears to no longer be linear, it should be replaced.

  • Page 41: On-Site Checklist

    Once pre-dive checks have been completed, DO NOT shut down the oxygen supply via tank valve. Doing so has killed many CCR divers. WARNING Never don a CCR with the oxygen cylinder turned off. FATHOM Mk III CCR User Manual...

  • Page 42: Disassembly And Cleaning

    Note: do not perform a quick cleaning on a moving boat to Set aside to dry with the mouthpiece in the avoid damage to the head or salt spray from entering the unit. open position. FATHOM Mk III CCR User Manual...

  • Page 43: Head

    If evident, remove the oxygen sensors and rinse the head thoroughly with fresh water. Inspect o-rings for damage and clean away and sorb dust or any other residue. Dry contacts and re-install oxygen sensors. Set the head aside to dry. FATHOM Mk III CCR User Manual...

  • Page 44: General Care And Maintenance

    General Care and Maintenance Other than a bi-annual (every two years) factory service, the FATHOM Mk III CCR requires little additional maintenance. However, certain components should be inspected for wear during unit assembly and disassembly. Replacement Oxygen Sensors Sensors should be replaced if or when any...

  • Page 45: Dsv/Bov

    After complete reassembly, be sure to perform a flow check on the BOV. Note: this procedure is identical on the DSV. FATHOM Mk III CCR User Manual...

  • Page 46: Mushroom Valve Replacement

    Replace DSV/BOV mushroom valves components are standard Apeks brand and can › Clean and service DSV/BOV be serviced by any qualified Apeks technician. › Clean and service oxygen regulator › Clean and service oxygen and diluent MAVs FATHOM Mk III CCR User Manual...

  • Page 47: Technical Specifications

    Maximum depth: 600 fsw (180 msw) › Scrubber duration with 8.8 lb/4 kg radial: ~9 hrs @ 0.7 cfm/20 lpm. › Scrubber duration with 5 lb/2.3 kg radial: ~5 hrs @ 0.7 cfm/20 lpm. FATHOM Mk III CCR User Manual...

  • Page 48: Appendix

    Appendix Mk III CCR O-ring Kit Periodic Checklist Build Checklist On-site Checklist Pre-dive Checklist FATHOM Mk III CCR User Manual...

  • Page 49: Mk Iii Ccr O-Ring Kit

    Needle Valve 2-008 Needle Valve 2-006 Oxygen MAV Cartridge FATHOM Mk III CCR User Manual FA THOM Dive Systems LLC | 41 13 NW 6th St, Suite A, Gainesville, FL 32609 | +1 352 213 8486 | info@fathomdive.com | www.fathomdive.com...

  • Page 50: Periodic Checklist

    Increase pressure to 2 ata (14.7 psi/1 bar) and record mV initial Evaluate for linearity and current limiting (<10% deviation) initial Cell Air @ 1 ata /0.21 wx 2 @ 1 ata @ 2 ata Date FATHOM Mk III CCR User Manual...
  • Page 51 Pneumatics (MAVs, wing, drysuit) initial CALIBRATION Flush with 100% oxygen initial Record oxygen mV @ 1 ata initial Evaluate for linearity and current limiting (<10% deviation) initial Calibrate handset and HUD (if required) initial Date FATHOM Mk III CCR User Manual...
  • Page 52 VERIFY GAS › Analysis › Pressures PRESSURE TESTS › Positive › Negative On-site...
  • Page 53 TURN ON › All gas › Handset & HUD ››› DON UNIT ‹‹‹ TEST › Bailout regs › Inflation Pre-dive › MAVs Checklists PREBREATHE › 3-5 mins › Set needle valve › PO > 0.7 ››› SPLASH ‹‹‹...
  • Page 54 FATHOM Dive Systems LLC 4113 NW 6th St, Suite A, Gainesville, FL 32609 +1 352 213 8486 info@fathomdive.com www.fathomdive.com...

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