I was certified NSS-CDS Cavern in '01, and my manual states the following limits;
If I find a NACD Cavern diver to dive with I am wondering what are the differences in our training limits.
For example; my cavern manual says I am beyond cavern diving if I can not see the entrance/exit, the ambient light zone is cave diving teritory. A crack in the roof that I could directly see the sun through, but could not dive through in buddy formation (restricted), does not change it from being the "ambient zone." Only direct sight of the entrance/exit makes it the "direct sunlight zone."
The third person NACD Standards I have seen have just said "The Cavern Diver must always stay within the daylight zone of the cave system. While it is not necessary to have view of the physical opening to the cavern, clear view of ambient light radiating through that opening must be plainly visible."
I am also wondering if how long ago the Cavern cert happened makes a difference for NACD? Current NSS-CDS Cavern limits are different from my 10 years ago NSS-CDS Cavern limits.
halemanō;3532716:Direct Sunlight Zone - diver can see the opening (entrance/exit). If you can not see the opening but it is not pitch black, you are in the ambient-light zone. When it is pitch black and you can see nothing without lights you are in the zone of total darkness. Cavern diving is only in the direct-sunlight zone.
130' Maximum Linear Distance from the Surface - Cavern divers must stay within a linear distance of 130' to the surface. Linear distance includes the depth of the entrance plus the distance of penetration. Examples; 30' deep entrance plus 100' penetration, 50' deep entrance plus 80' penetration, 70' deep entrance plus 60' penetration.
70' Max Depth - Below 70' air reserves for dealing with emergencies are too limited and the margin for error becomes too critical.
No Restriction - Buddy teams should be able to comfortably swim side by side. If divers have to swim single file due to localized narrowing that is considered a restriction. Cavern divers are not permitted to pass through restrictions in part because sharing air with standard scuba through a restriction is nearly impossible.
40' Minimum Visibility - The minimum visibility acceptable for cavern diving is 40'.
No Decompression Limits - Cavern divers should stay well within the no-deco limits. When cavern diving, bottom time is the time from leaving the surface until returning from the cavern to a depth of 10' in open water(not ending at start of ascent). Most experienced cavern divers stay within 80% of NDL limits, to allow for any unexpected delays during exit.
Air Supply Limitations - One of the three leading causes of death in underwater caves is failure to reserve adequate air for exiting. This requires at least as much air in each cylinder as both divers (buddy team) used coming in on the two seperate cylinders (basic rule of thirds).
If I find a NACD Cavern diver to dive with I am wondering what are the differences in our training limits.
For example; my cavern manual says I am beyond cavern diving if I can not see the entrance/exit, the ambient light zone is cave diving teritory. A crack in the roof that I could directly see the sun through, but could not dive through in buddy formation (restricted), does not change it from being the "ambient zone." Only direct sight of the entrance/exit makes it the "direct sunlight zone."
The third person NACD Standards I have seen have just said "The Cavern Diver must always stay within the daylight zone of the cave system. While it is not necessary to have view of the physical opening to the cavern, clear view of ambient light radiating through that opening must be plainly visible."
I am also wondering if how long ago the Cavern cert happened makes a difference for NACD? Current NSS-CDS Cavern limits are different from my 10 years ago NSS-CDS Cavern limits.