Brock Technical

Fathom MK3 CCR

The FATHOM Mk III CCR is designed to be the simplest and most intuitive closed-circuit rebreather for underwater exploration. Several years ago, as their dives became increasingly deeper and longer duration, Karst Underwater Research (KUR) divers recognized the need for a new closed-circuit rebreather (CCR) with excellent work-of-breathing and long scrubber duration that would stand up to the rigors of cave exploration. The short list of desired features included:

  1. A radial scrubber for the best possible work-of-breathing and scrubber efficiency,
  2. At least an 8 lb/3.6 kg scrubber capacity for long duration dives,
  3. Back-mounted counter-lungs to maintain streamlining and easy stage-bottle handling,
  4. Off-board gas addition capability for diluent/bailout, and
  5. Mechanical oxygen addition for reliability.

Unable to find an existing unit that met these requirements, KUR diver Charlie Roberson started to design what would eventually become the FATHOM CCR. There are no easy decisions when it comes to rebreather design and every choice, every dimension, every o-ring, was debated endlessly with fellow KUR divers. Ultimately, the final decisions were Charlie’s and his background as a machinist in the US Navy and Hogarthian/DIR cave diver guided him towards simplicity and functionality. The result of these efforts was the FATHOM CCR. Refinements to the original design continue and the FATHOM Mk III CCR is the latest version. You can learn more about the Fathom MK3 here

We are able to teach you from the very beginning of rebreather diving, all the way through CCR Hypoxic Trimix. Please see our other course offerings for advanced CCR training.

Certification is through IANTD.

  • If you lack prior CCR experience, there is a five-day program that will take you all the way through to full CCR Diver certification.
  • If you are already certified on another CCR, there is a two-day crossover program that will make you a fully-certified Fathom MK3 CCR Diver.

If you have no prior CCR experience:

  • Be at least 18 years old
  • Have at least 50 logged dives
  • Be certified to the Advanced Nitrox/Deco Procedures Diver level or equivalent

If crossing over from another CCR certification:

  • Have logged at least twelve CCR dives
  • Have made at least one CCR dive in the past 45 days
  • The “from scratch” CCR course takes five days and at least 400 minutes of bottom time.
  • The crossover course takes two days and at least 200 minutes of bottom time.
  • With sufficient notice, we can usually accommodate requests for specific course dates.

Contact us for pricing