Rebreather Diving

Test Your Knowledge: Open Loop

By April 30, 2015 No Comments

Question: It is always recommended to carry a bailout bottle when diving deeper than 18m/60 feet deep, but how would you handle an emergency situation if your bailout second stage was breathing wet and you did not have a BOV on your unit?

Answer: Let’s face it. You have had a really bad day if you bailed from your rebreather to your bailout tank only to discover that your second stage is filling up with water. The good news is that you can still access the gas in your diluent tank and bailout tank while breathing with a technique that is called “open loop breathing.” With this technique, you use your ADV to fill the inhalation counterlung. With the rebreather mouthpiece in the closed circuit position inhale the fresh gas and then exhale through your nose or around the edges of your lips. Press the ADV to fill the bag again and take your next breath. Each time you need a breath, flush the bag with fresh gas, inhale and then dump the gas as with open circuit breathing.

The best news of all is that this should be very preventable. Each time you go for a dive, ensure that you practice a bailout drill, both using the BOV (if you have one) and the bailout tank and regulator.

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Author Jill Heinerth

Cave diving explorer, author, photographer, artist

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