amir4arkan
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آیا میزهای غواصی نیروی دریایی ایالات متحده محدودیتی در تعداد غواصی در روز دارند؟
Do the dive tables have a limit on the number of dives per day?
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A few more details of what's behind your question might help .... oh and in English too, I doubly many people reading this will understand Farsi.
No, except for deco and oxygen limits.
tmassey
Contributor
Yeah, I can’t read the body, but I can read the title…
PADI dive tables (added: and US Navy tables) for example, don’t specify a limit. They have a procedure for tracking multiple dives using the interval between them. If you continue to follow the procedure, it will continue to spit out a number.
A few notes: first, if your surface interval is below a certain length, you’ll still need to keep handling your dives as multiple dives, even if they occur on different days. For example, if you do a dive every 4 hours for two days, you’d never stop doing multiple dives even when the calendar switches.
Second, the farther you get down the multiple dive path, the farther you get from the data that was used to make the chart, and the farther you get from the people before you who safely used the chart. Two dives in relatively quick succession (say, 45 to 60 minutes in between) is extremely well tested. Four dives with a bit longer between them, also well tested. Even five dives in a day has been done — that’s the most I’ve ever done (but not using tables: I had a computer),
Beyond that typical profile, you will likely have less confidence. That means shorter intervals between dives or more dives per day and you will take on more risk. There are also different mechanisms that may add risk that are not covered by tables at all: like what happens when you recompress bubbles too soon after they’re formed (from a too-short surface interval) and they get on the arterial side of your circulatory system.
For me, the limit was never the tables. After four or five decent dives (not just a few minutes down and up), I’m dead tired. I can’t imagine wanting to do even more…
I hope that helps. If you would like more information, I’d be happy to give what I can, but English is all I got to give.
PADI dive tables (added: and US Navy tables) for example, don’t specify a limit. They have a procedure for tracking multiple dives using the interval between them. If you continue to follow the procedure, it will continue to spit out a number.
A few notes: first, if your surface interval is below a certain length, you’ll still need to keep handling your dives as multiple dives, even if they occur on different days. For example, if you do a dive every 4 hours for two days, you’d never stop doing multiple dives even when the calendar switches.
Second, the farther you get down the multiple dive path, the farther you get from the data that was used to make the chart, and the farther you get from the people before you who safely used the chart. Two dives in relatively quick succession (say, 45 to 60 minutes in between) is extremely well tested. Four dives with a bit longer between them, also well tested. Even five dives in a day has been done — that’s the most I’ve ever done (but not using tables: I had a computer),
Beyond that typical profile, you will likely have less confidence. That means shorter intervals between dives or more dives per day and you will take on more risk. There are also different mechanisms that may add risk that are not covered by tables at all: like what happens when you recompress bubbles too soon after they’re formed (from a too-short surface interval) and they get on the arterial side of your circulatory system.
For me, the limit was never the tables. After four or five decent dives (not just a few minutes down and up), I’m dead tired. I can’t imagine wanting to do even more…
I hope that helps. If you would like more information, I’d be happy to give what I can, but English is all I got to give.
OP
amir4arkan
Registered
Do US Navy dive tables have a limit in the number of dives in one day?
OP
amir4arkan
Registered
Not any more and not in your lifetime. As near as I can tell, repetitive dive tables were limited to two/day when the they was first introduced in the early 1950s (late 1940s?). That limit was removed by the time the 1959 manual was published, but that "convention" was followed into the early 1970s by many Navy and commercial diving supervisors.
I could not find any reference to repetitive air dives in the 1943 US Navy Diving Manual. The repetitive dive tables looked about the same in the 1959 manual as they do today. I don't have a copy of the 1952 manual.
A dive on US navy tables carries a penalty which puts a diver in a set repetitive group, A surface interval gives a credit which can be offset against the penalty. An exceptional exposure dive doesn't have a repetitive group so only one can be made in a day .
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