This document was last updated on November 19th, 2022
The FATHOM Mk III CCR features a Shearwater Petrel 3 handset on a 4-pin AK cable as the primary display with the new FATHOM Heads Up Display (HUD) as the secondary display. The Petrel 3 features a new haptic alarm feature for low or high PO2. The handset can be replaced with a Shearwater NERD 2 on a 4-pin AK cable if desired. The 4-pin AK cable allows the Petrel 3 handset or NERD 2 to be removed from the head for transport and storage.
The FATHOM HUD utilizes a modified Smither’s code to display current PO2 information from all three cells. The HUD is powered by a ½ AA SAFT battery, which is housed in an external battery compartment on top of the head. A piezo switch on the head is used to calibrate and turn the HUD on/off. On startup, the HUD indicates battery voltage through a series of flashes. The ½ AA SAFT battery lasts for 200+ hours due to the incredibly low power consumption. The LED display is reversible so can be worn on the right or left side while keeping proper left to right cell orientation and automatically adjusts brightness to ambient light conditions. The FATHOM HUD features a user definable visual alarm for low or high PO2 scenarios