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The Lungfish ORCA has been designed from the ground up to combat the major causes of rebreather accidents. Our key safety features are standard on every Lungfish unit.  These features have been accomplished with minimal additional complexity, so as not to burden the diver with additional equipment that would itself have a chance of failure.


Protects against Hypoxia

A rebreather is safest and most comfortable to dive with if the volume of the counterlungs (breathing bags) are similar to the movable volume of the diver’s lungs. Too small and the diver cannot take a full breath, too large and buoyancy control and maintenance of oxygen level are made more difficult.

Rather than offering different size counterlungs for different users, our systems are customer sizeable: during setup, the diver breathes into them and then closes the casing, instantly adjusting them to the correct size.

As well as rocksteady buoyancy, this gives an extra security factor against the insidious risk of hypoxia. Other than at extreme depth, in any failure of gas supply, even if the alarms go unnoticed, the change in breathing volume is likely to become obvious to the diver well in advance of the oxygen level becoming dangerously low, permitting corrective action to be taken.


Protects against drowning, caustic cocktail and system failure.

The design of our scrubber and counterlungs makes it difficult for water to get in, and easy for water produced by the scrubbing reaction to drain out.

Should you lose your mouthpiece, the Lungfish is one of very few rebreathers where it is possible to recover from a system flood. Not only this, but the system can be purged with zero disruption to your buoyancy and trim.

The unique electronics pack is designed to minimise the chance of water damage by directing liquids away from the cells. With sealed sensor bases and no exposed wiring whatsoever, even a total flood will not cause permanent damage although the cells may no longer read correctly. It is straightforward to check the O2 cells underwater, use the CO2 monitor to check scrubber function, and make the call as to whether to continue or bail out.


Protects against CO2 poisoning

Lungfish rebreathers are equipped as standard with a robust CO2 monitor, well proven in naval use. This gives a real-time indication of scrubber performance, to alert you to the presence of any CO2 well in advance of it becoming a risk. Unlike other systems, this works reliably regardless of depth or background gas.

The CO2 concentration of your inhaled gas is shown on the default dive screen, while two alarm levels warn of a low level of CO2, indicating a functional though depleted scrubber, and a higher level that would necessitate bailout. You can easily decide whether you can purge the loop, reduce your exercise rate, and finish the dive closed-circuit, or stay bailed out.


Protects against Hyperoxia / Oxygen Toxicity

Lungfish’s electronics continuously monitor the readings of three oxygen sensors. Any faulty or suspicious sensors are removed from the calculation of PPO2, and the diver is alerted.

The electronics also monitor themselves for malfunction so any damaged parts are automatically isolated so the critical functions are not compromised.

Furthermore, the Lungfish is provided as standard with the Calibration Cap. Most rebreathers are calibrated at 1 atmosphere of oxygen and yet operated at far higher levels. Limited cells unable to read high levels will only become evident at depth. On a Lungfish, it is straightforward to check the cells at alarm levels and beyond, simply by holding down the cap. This consumes minimal oxygen and ensures that every dive can be undertaken with maximum confidence.

This removes the risk that under-reading cells might cause a diver to suffer oxygen toxicity.

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