SEALS, Drager, 02 toxicity

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JustAddWater

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The other evening I watched a show on The Learning Channel about the U.S. Navy SEALS involvement in the operation to apprehend Panamanian President Noriega. It said that the SEALS, using Drager rebreathers, were limited to a depth of 25 feet due to the risk of oxygen toxicity and getting the bends. Is this because these rebreathers used a higher % of oxygen? Is this the norm for rebreathers used today?
Thanks,
JAW
 
Hello,

If they was limited to 25' max then it was probably oxygen rebreathers.

Ed
 
JAW...

I caught the same point when I was watching it.

From what little I know about them rebreathers can go to the same depths that Nitrox diving can take you. Plus if you think about it, the large Halcyon rebreather is what George Irvine and company are using in the WKPP pushes (as documented on the OLN network this past fall).

Perhaps the Discovery Channel folks were trying to put in a bit of "misinformation" for the non-divers about the capability of the SEAL's equipment.
 
Though it sounds like an O2 rebreather, the confusing part is the statement "and the bends."

Roak
 
The military uses o2 rebreathers in situations where they need long dive time and will be shallow depths. The military actually allows an o2 partial pressure of 1.9 which would be 30 ft, but would reduce allowable time. They probably had some expected time duration so reduced max depth to 25 ft which would have a longer allowable BT than 30 ft. O2 rebreathers are very simple devices and as long as there is a supply of o2 and the loop is not compromised there really isn't anything that can fail, the divers only has to worry abouth depth, since only o2 is in the loop gas only has to be added to maintain loop volume.
 
Thanks for the info. I too thought it confusing when they used the term "the bends". Could they be using it as a catch all phrase for any/all diving maladies?
 
Typical TV show - "Should be used for entertainment purposes only".

I believe the narrator said the divers had a MOD of 25 feet or they could suffer "oxygen poisoning" or the "bends". Later, the divers had to dive to the bottom (50 fsw) to wait for a cargo ship to pass over.

If the SEALs were on 100% O2, then saying "they could get the bends" was in error (or used for dramatic effect).

If they really went to 50 fsw on 100% O2, then they hit a PPO2 of 2.5.

Who knows? (That's a retorical question.)
 
Hello,

OK people. Studies have shown that you CAN, I repeat *CAN*, get 'oxygen bends'. Most cases disappears with in 10-15 mins after surfacing. In the usn diving manual it's refered to as "off-effect". By limiting depth and ascent rates you minimize the risk, obviously.

For more info on this effect please refer to AEDU documentation.


Ed
 
The show you all saw on TLC about the SEALS in Panama shows the SEALS diving the Drager LAR V Closed Circut Oxygen Rebreather. Yes, it uses pure O2, that's why you can't go very deep. If you go below about 20 to 25 feet for any leangth of time you run the risk of taking an "O2" hit. That means that your PO2 is above and exceptible level (1.6) for the mix you are breathing. This raises the divers Central Nervous System Toxicity and can cause a diver to convulse. By dropping to a depth for 50FSW and minimizing work leves and breathing slowly it is possible for divers to survive with high PO2.
 
How do you minimizes work levels and breathe slowly when the bad guys are dropping grenades and the Generals boat is about to explode? But it was a good program!
scubajoe
 
https://www.shearwater.com/products/teric/

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