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Old 5 July 2018, 10:59
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Quote:
Originally Posted by ricardo View Post
As an aside, is 60 hours in a decompression chamber the maximum time that someone has decompressed?
Not by a long shot. "Saturation diving" can cause a diver to rack up a substantial deco obligation. This involves breathing gas at pressure until tissues are saturated with the inert gas (i.e can't absorb more gas) in the breathing mixture. It takes roughly 24 hours to fully saturate for any depth (assuming the slowest tissue saturates in about 4 hours at a given pressure, which probably isn't quite true for some tissues). Then the divers work for several days or weeks with surface support. Commercial divers do it in some cases because it's more efficient than repeatedly surfacing and decompressing. The decompression rule of thumb for saturation diving is one day in the pot per 100 feet sea water plus one day, with dive + deco time no greater than 28 days. So a 700 foot saturation dive would incur an 8 days decompression obligation.

And before you ask why it takes so little time to saturate but a longer time to off gas, it's because when saturating you're not worried about bubbles forming, but when desaturating you're trying to manage bubbles. It's like shaking a soda for 5 seconds to get it ready to blow, then spending 30 seconds slowly releasing the gas so it doesn't fizz. Same basic principle (sort of).

In theory, if the the water in the cave does not exceed a pressure of 1.5 ATA (roughly 15 feet), they can spend days in that pressure without having to decompress, iirc, but I'd have to check a table to be sure.
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