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related to decompression sickness

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I'm not very aware of diving ... So what i understood from this text ... is that if you dive undersea for an hour at depth of 190 feet ... you need to ascend to the sea level gradually for 3 hours to avoid decompression sickness hazards ?

and this schedule in the text ... means that the divers should wait for 10 minutes when he ascend to 50 feet then 17 mins wait at the 40 feet and so on ?

Am i right or wrong ... if wrong please clarify it to me ...  & thank you

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Please be aware the the Navy diver tables have a significantly smaller margin of safety than civilian sport tables.

You are correct in thinking that the decompression from 190 feet needs to be done in stages.

The time of dive at the max depth is known as bottom time and one hour at this depth would be a huge bottom time.

The decompression time is almost always longer than the bottom time.


As a comparison, using PADI dive tables I can get only about  4 to 5 minute bottom time at on the wrecks at the bottom of Lyme Bay ( there is a WW1 submarine down there), at a depth of 40 metres (130 feet).


This is using plain compressed air.

This is also why divers going below 30 metres tend to use special gas mixtures. The decompression tables for these are quite different.

Edited by studiot

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Thank you Very much John and Studiot ...


Studiot ... I really appreciate your clarification ... sounds pretty much solid and persuading but as you mentioned PADI and looks that you have experience in the filed ...


This table over here ... taken your example of Lyme Bay ... You can stay from 3 up to 10 mins maximum ( same as you said ) ... saying you have been down for the 10 mins ... You have to go up to surface and stay for an hour outside water ... Now you're Group B pressure ... So if you want to go down again ... You can't stay in the depth of 130 feet for more than 5 mins ... Right ??

and another question .... what if  after staying for 10 mins at 130 feet and going out ... for 5 hours ( which is exceeding the maximal written Surface time ) .... Does staying for 5 hours means that you can dive as you haven't been in water for a week ... I mean without taking into consideration ( the surface time interval )


Really appreciate your help!

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