Deep Dive first

[MikeFerrara]

BRW,
Could you explain what you were refering to in this sentance from your last post please?

"And additional time for repets on
forward profiles is a hangover from haldane dissolved gas
models and tables ONLY. "

Thanks.

 

[Dr Deco]

Dear Readers:

Some interesting comments were made by sheck33 in his recent posting regarding the US Navy tables. Having worked in the field of decompression physiology since 1969, perhaps I can offer some insight into these aspects.

US Navy Tables and Recreational Diving

The US Navy will be the first to say that their tables were not developed for the recreational diver. Their position would be, “If you want to use them, go ahead.” They were developed for decompression diving and only the NDL portions of USN tables are used for recreational scuba.

The USN tables have repetitive groups based on the 120-minute compartment. This is necessary for decompression diving if all profiles are to be covered and simplified tables printed. Tables with repetitive groups based on a 60-minute compartment were developed by Rogers and PADI/DSAT.

We could also add:

• Much of USN deep operations switched to saturation diving in the 1970s thus obviating the needed for bounce dive tables;
• USN later developed an interest in bounce tables with a variable decompression time (1990s) that was linked to operational risk (such as SEAL missions);
• Current USN interest is in cold-water diving (linked to problems encountered in Long Island Sound and the TWA recovery work), and in disabled submarine crew rescue (change in goals with the breakup of the USSR).

Deep Stops

- Deep stops were first described in recent decades by Brian A. Hills (Limited supersaturation versus phase equilibration in predicting the occurrence of decompression sickness. Clin Sci 1970; 38(2): 251-67). The reason given was somewhat different than that proposed today, but the end result was the same.

- A German group at the Institute of Aerospace Medicine’s Underwater Physiology Section also incorporated deep stops in the mid 1970s in their “Type f profiles.”

- Preformed bubbles were a natural consequence of the work of Strauss in Hawaii with gels (Bubble formation in gelatin: implications for prevention of decompression sickness. Undersea Biomed Res 1974; 1(2): 169-74). Yount followed this up in his VP model. These gel bubbles are not formed in the same manner as tissue bubbles (in my opinion) and the viscous gel is not really similar to tissue, but they led to an interest in deep stops.

- Richard Pyle gathered empirical evidence on deep stops during his fish collection work. This interested technical divers.

- Development of the deep stop models by Bruce Wienke, PhD, advanced this concept considerably by incorporating the stops into his decompression algorithms.

Dr Deco :doctor:

 

[Rick Murchison]

sheck33 once bubbled...
Let's take a specific example, using the Navy tables........

I learned how to dive with the Navy tables. I cant believe they still use them. These tables suck.

Ok...
Which tables would you like to use?
I ain't particular.
You pick the table, run the numbers, and show us.
Rick