Depth measurement in a cave

[seaseadee]

So my next question is this: If you are merrily diving along a sump and come out at an air space can you get bent because you ascended too quickly?

 

[DA Aquamaster]

Let's say you are diving in a cave and it descends to 300' before again rising to the surface at more or less the same 1 ATA. You'd have to do the same deco stops you'd normally do for the same dive profile in open water.

That's distinctly different than surfacing in an air bell where the pressure in the bell is equal to the water pressure at that depth.

 

[The Chairman]

Yeah, I don't think they hit 90ft of depth. One of the tunnels might have been 90ft long... but not deep. I don't think they were much deeper than 20 ft, but I'm not sure why I think this to be true.

 

[Jack Hammer]

Yeah, I don't think they hit 90ft of depth. One of the tunnels might have been 90ft long... but not deep. I don't think they were much deeper than 20 ft, but I'm not sure why I think this to be true.

Conflicting reports. I read versions that clearly stated one or the other, and other reports that were vague.

 

[The Chairman]

Conflicting reports. I read versions that clearly stated one or the other, and other reports that were vague.

and the boys swam out on oxygen bottles.

 

[KevinNM]

Let's say you are diving in a cave and it descends to 300' before again rising to the surface at more or less the same 1 ATA. You'd have to do the same deco stops you'd normally do for the same dive profile in open water.

That's distinctly different than surfacing in an air bell where the pressure in the bell is equal to the water pressure at that depth.

I’ve read accounts of people exploring caves that have a super deep, shallow, super deep profiles. It sounds like it sucks quite a bit.

 

[kensuf]

So my next question is this: If you are merrily diving along a sump and come out at an air space can you get bent because you ascended too quickly?

Yes. Look at the Pozo Azul explorations for examples, they had to do deco at the far end of several of the sumps. Quite an amazing bit of exploration has gone on there.

Pozo Azul - Cave Diving Beyond the Limits

 

[EireDiver606]

Yeah, I don't think they hit 90ft of depth. One of the tunnels might have been 90ft long... but not deep. I don't think they were much deeper than 20 ft, but I'm not sure why I think this to be true.

Yes I heard that they were using oxygen tanks, there’s another thread that highlights how confusing it is that reporters think all tanks divers use are oxygen and the fact that they could have actually been using oxygen.

I think you’re right though.

 

[The Chairman]

It sounds like it sucks quite a bit.

It certainly has its ups and downs.

 

[rjack321]

90 Feet comes from the very first post.
I stated it would depend on the elevation of the cave.

Pretty sure there was no 90ft sump dive in that exit. Media reports are contradictory but at least a couple say they were using FFMs in positive pressure mode fed by cylinders of 80% - which has a MOD of 30ft.