CCR max depth?

[ajduplessis]

1000ft for ccr is very very deep. Divers typically switch to OC deeper that 300ft, I see this a lot. That said Don Shirley used to dive dual and modified inspos to 600ft. I dont know ccr but was under the impression most factory units have max depth of 300ft??

 

[down4fun]

1000ft for ccr is very very deep. Divers typically switch to OC deeper that 300ft, I see this a lot. That said Don Shirley used to dive dual and modified inspos to 600ft. I dont know ccr but was under the impression most factory units have max depth of 300ft??

I have multiple dives in the 400-650 ft range on a basically factory unit. Removal of a environmental seal was the only modification.

 

[jord1990]

Ok guys whe are at the enemy harbor.
Just 8 hours of deco left.

Nope I wouldn't see that working out.

 

[Akimbo]

I saw that episode. 1000' on a CCR is no problem at all if you have a saturation dive system aboard a nuclear submarine to support you.

Blind Man's Bluff: The Untold Story of American Submarine Espionage: Sherry Sontag, Christopher Drew: 9780060977719: Amazon.com: Books

Navy sat divers were doing the work described in this book in the 1970s on eCCRs, more or less GE Mark 10s. Who knows what is going on today.

---------- Post added October 11th, 2013 at 08:49 AM ----------

Ok guys whe are at the enemy harbor.
Just 8 hours of deco left...

8 hours? More like 10 days. You don't go to 1000' just to touch the bottom and head back. Just getting to 1000' puts you on a saturation decompression table due to the slow descent rate (in a chamber) to avoid HPNS symptoms. My brother made a dive to 600' on a fast blow-down that only took 3 hours. He and his bell mate could hardly climb the ladder to the bell due to compression pains.

 

[asimpkinsjr]

Personally I think when speaking about record-depth dives, it is best to avoid citing people who died doing them. But maybe that's just me.

lol, this mad does have a point

 

[Dsix36]

Everybody gets all excited about the max depth of this or that. Any dummy can take a CCR or OC to any fool depth that they want to. That is the easy part, getting your butt back up alive is where the problems generally are. The most important part of these dives is proper planning.

 

[formula1mb@aol.com]

928 ft CCR dive on dual rebreather:

283m descent on Vimeo

283 meters (928.5 feet) on DualRebreateher in Dahab, Egypt. - Page 5 - Rebreather World

 

[Jared0425]

Is it possible for them to deploy out of the sub at around 1000ft and make a rapid ascent to their target? I would imagine automatic deco, but for how long?

 

[Subcooled]

the commentator said that stopped me in my tracks what that Seals could make 1000 ft depth dives on a "mixed gas CCR" and it frankly caught me off guard...is there anyone who can see or conceptualize how this is possible, even with military tech? to me it just seems to be too much of a stretch. The commentator literally said "divers have gone further than 1000 feet....I almost fell off my damn chair...thoughts?

I've heard of some really deep hydrox dives done by the French Comex corporation.

Wikipedia confirms: "of the Comex S.A. industrial deep-sea diving company performing pipe line connection exercises at a depth of 534 meters (1752 ft) of sea water (MSW) in the Mediterranean Sea during a record scientific dive."

Now, that's a pretty deep dive.

I don't know if it was done on rebreather or OC, but given that extreme depth, any OC tank would be depleted extremely fast. Maybe they had diving bell supplied air?

Unfortunately, and this is a rumor only, the hydrox mixture used at that depth caused a permanent and highly unwanted change in personality. Someone may look up the facts. Mixing hydrogen and oxygen, too, is a little bit delicate.

Air, and trimix, gets thicker with depth/pressure, and this affects its flow in the scubber. People in my diving club that know more than I do, say that at great depths the scrubber lasts a shorter time due to the thickness of the gas.

 

[Doppler]

Air, and trimix, gets thicker with depth/pressure, and this affects its flow in the scubber. People in my diving club that know more than I do, say that at great depths the scrubber lasts a shorter time due to the thickness of the gas.

In a more perfect world, scrubber duration would be measured in terms of the capacity of the scrubber material to bond with X litres of carbon dioxide. Since there is a relationship between consumption of oxygen in litres and the production of CO2 this is reasonably easy to work out. The rate at which oxygen is consumed is a "constant" and is unaffected by depth; however, depth does seem to effect the potential for CO2 break-through. I had not read it being attributable to gas density -- makes sense. I was taught that gas density affects dwell times and flow rate, which in turn impacts the "geometry" of the area of the scrubber bed that is most active. I guess the end result is the same!

Anyway, thanks for making me think about something I had not really analyzed for myself. I just always start a dive deeper than 45 - 50 metres with fresh scrubber.