Innovation in diving

[gianaameri]

Gian...gastimate or guesstimate still a guess. So I have my numbers on a contingency plan for the situation posed, waiting to see yours first though. I'll admit was awkward for me using the metric system (us silly imperial's). But I still want to know what yours was and how much of the 1/3 reserve you came out with. I applied an uncertainty equation based on gas, depth and speed using fractional and percentage to derive my answer. I think its fair to assume you are a calm diver with good form and skill set so my numbers were based on conservative and ultra high liberal swim and problem solving times (+- 2 min). Simply saying you could because you guessed is not an acceptable answer. Numbers please. You don't have to use an uncertainty equation like I did but please show your work.

Sent from my DROID RAZR HD using Tapatalk

It is not a wild guess. It is an estimate of the gas required based on the known parameters, prior experience, and adding a margin of safety.

Nonetheless it is a gas estimate = "gastimate."

That is what I like calling it (but you call it what you want).

Take a cave course, get some experience, and work out what "gastimate" works for you for your intended dive.

So, should we close this thread or Tony or someone else can tell me how the Dive Computer which I did not have that day and chose not to carry on the dive (as I did not have it) could have saved my life on what was virtually an impossible dive to get into a deco situation?

---------- Post added January 8th, 2014 at 01:11 PM ----------

We would rather calculate gas requirements that gastimate.

So I am totally sure that you did a saftey stop prior to surfacing in the dry chamber?

I slow down on ascents as required/feel throughout the dive. It is yo-yo diving, so every-time the cave line angles up denoting an ascent I slow down and in some cases "stop and go." Just common sense.

 

[Dr. Lecter]

Not aware of how one can monitor depth in unknown territory without a depth gauge. So awareness of depth was missing from this part of the dive, which counters Gian's insisting that he knew his depth from the line.

If he knows his SAC, the SPG might be enough: volume drop, time elapsed, and SAC will give depth. Of course, he's guessing on time and most SPGs aren't the most accurate of gages nor given the finest gradation markings.

 

[gianaameri]

If he knows his SAC, the SPG might be enough: volume drop, time elapsed, and SAC will give depth. Of course, he's guessing on time and most SPGs aren't the most accurate of gages nor given the finest gradation markings.

The depth I know from the cave line. I am not guessing depth in any way. The cave line demarks the depth at various points in the cave and in between those points.

No cave line denoting the depth, it would not be possible to do the dive without a Dive Computer/Bottom Gauge.

The depth at those points on the line and across the line is known to me from prior dives and the cave topographical map, and from that I also know what the dive profile is in terms of depth.

The cave line also gives me distance between the waypoints (where the line is secured in the cave from one cave formation to the next) in the cave.

The unknown is time (which needs to be estimated).

 

[Dr. Lecter]

The depth I know from the cave line. I am not guessing depth in any way. The cave line demarks the depth at various points in the cave and in between those points.

While I'm contradicting my own advice, I'm sure we'd all love to hear how you knew depth from this portion of the line that was allegedly new to you:

exploring a line [/B]the very last bit (leading to a small dry chamber) I never dared to follow before with the rebreather due to size/buoyancy considerations

 

[gianaameri]

While I'm contradicting my own advice, I'm sure we'd all love to hear how you knew depth from this portion of the line that was allegedly new to you:

Because the line was departing the main line and ascending from my known depth to the surface at about a 70 degree angle then entering into a dry-chamber.

I was going up, ascending, and off-gassing - not a deco issue - knowing my depth would be progressively less till it would be 0 (atmospheric pressure only, no water pressure).

Time was not an issue either at 0 meters depth (not on-gassing), but of course I was breathing from the 2nd stage which means I was using up my gas.

Guys, run a line in some open space on land with small hills and small valleys (variations in the terrain) and then pretend it is underwater and follow that line, and you can understand (imagine water covering just the uppermost part of the hill and that being your entry and exit point.

If the vertical distance form the hill to the valley is known to you (equating to depth in a cave), then you do not need a measuring instrument with you because that vertical distance is static/fixed (once you know it, it is always the same).

Furthermore, you will know the distance between each of the points (i.e. trees, shrubs, rocks...) you have secured that line to. That will remain fixed and after you measure it once, that is it, you know it, and it will not change.

So, that line is your dive profile in terms of depth and distance.

Follow the line from one end to the other and time yourself. Do it 400 times, and then you also have a pretty good idea of time from point to point and beginning to end.

Blindfold yourself and do the same, and do the same jogging, and you know the run-time under the three conditions (i.e. slow, normal, and fast).

The cave where I dive is non-tidal. Now, bear in mind if you have tides of say 10 meters, then the above does not apply insofar you depth will change with the tide level on that particular day and time.

 

[Omisson]

I have barely followed this discussion, but I just want to remind people that according to the PADI RDP for EANx 32, the NDL for a 12 meter dive is over 3 hours. The PADI RDP intentionally uses shorter first dive bottom times than is necessary in order to allow the diver back in the water sooner for a second dive.

I was recently working on my scootering skills in a cave (Jackson Blue in Marianna, Florida), and I just went back and forth not far from the entrance, so that if the scooter conked out at the worst possible time, I could swim out easily. The depth of my dive in that section did not vary by more than a few feet. It is a high flow cave with no silt to speak of, so there was no possibility of a silt out. Now, I was fully equipped for the dive with all the instruments I could possibly need, but I just thought I would point out that it is possible to use a scooter safely in a cave that does not have much difference in depth where you are swimming and with no chance of a silt out. I don't know if this was the case here, but it is possible.

Except:

A) according to him, his depth was 12 meters- but he still refuses to disclose what cave system has a 400 meter penetration run that never exceeds 12 meters of depth.... I've tried to locate the cave based on those depths in Mallorca- but none meet these criterion.

B) his depth wasn't just 12 meters- it went to 18 meters for unknown amounts of time.... It averaged 12....

C) he also - apparently- surfaced in a dry cave at least once in the middle of the dive (recent addition) making it a severe bounce dive.

D) entered a previously unexplored section of cave with unknown depth and length data.

All this while purportedly diving over 140 bar without a dive computer, depth gauge, bottom timer, dive tables, but on a DPV with penetration over 400 meters....

Those of us with Cave training find this very suspect.

Dan-O

 

[TONY CHANEY]

OK, let's assume that everything was as Gianaameri says it is. I would love to dive this cave, so which cave is it? Gianaameri you can feel free to PM me and I will tell nobody...just one caver to another.

 

[gianaameri]

OK, let's assume that everything was as Gianaameri says it is. I would love to dive this cave, so which cave is it? Gianaameri you can feel free to PM me and I will tell nobody...just one caver to another.

From the questions you have been asking it does not appear you are a cave diver (and I do not know you).

Are you?

---------- Post added January 9th, 2014 at 02:01 AM ----------

Except:

A) according to him, his depth was 12 meters- but he still refuses to disclose what cave system has a 400 meter penetration run that never exceeds 12 meters of depth.... I've tried to locate the cave based on those depths in Mallorca- but none meet these criterion.

B) his depth wasn't just 12 meters- it went to 18 meters for unknown amounts of time.... It averaged 12....

C) he also - apparently- surfaced in a dry cave at least once in the middle of the dive (recent addition) making it a severe bounce dive.

D) entered a previously unexplored section of cave with unknown depth and length data.

All this while purportedly diving over 140 bar without a dive computer, depth gauge, bottom timer, dive tables, but on a DPV with penetration over 400 meters....

Those of us with Cave training find this very suspect.

Dan-O

I do not think you are a cave diver based on what you write above.

 

[Omisson]

From the questions you have been asking it does not appear you are a cave diver (and I do not know you).

Are you?

I do not think you are a cave diver based on what you write above.

I am Full Cave (Apprentice) in the NSS-CDS, and serve on the Nominations Committee of the NSSCDS. Also an associate member of the NACD... And am TDI Normoxic Trimix certified. You want my ID numbers?

I trained with both Jim Wyatt and TJ Johnson... Both are known just a BIT in Cave training...

So I showed mine- what agency certified you?

What cave was it you did your 400meter penetration never exceeding 12meter depth ?

Dan-O

 

[gianaameri]

I am Full Cave (Apprentice) in the NSS-CDS, and serve on the Nominations Committee of the NSSCDS. Also an associate member of the NACD... And am TDI Normoxic Trimix certified. You want my ID numbers?

I trained with both Jim Wyatt and TJ Johnson... Both are known just a BIT in Cave training...

So I showed mine- what agency certified you?

What cave was it you did your 400meter penetration never exceeding 12meter depth ?

Dan-O

The penetration was 600 meters.

I exceeded 12 meter depth several times. 12 meter depth was the average depth.

The cave (as is the case with many caves) varies in depth throughout its extension. There is about Km 15 of lines and it is still under exploration.

You enter the cave and it goes down to about 12 meters, then you go up to about 10, then down to 14, then for about 250 meters 13, then up to 3 meters, then back down to 15 meters, then up to about 10 meters, then back down to 14 meters, there I turned back so you reverse the lot, and after the 3 meter section went out a different way but it is about the same depths as described before except that at a point it drops to 18 meters, then it goes up to 6 meter, then it drops to 14 meters, then it goes up to about 10, there I surfaced very briefly to 0 (not really a big deal as you purport it to be to go up and then back down on a straight line leading to a chamber), then went back down to 10, then 12, and then slowly exited the cave to 0 meters/surface.

When I go in 2000 meters max. penetration (rounding up) to the NE there is a drop to 18 meters, then it goes back up to maybe 10, then up and down several times, and when I go in and then W it goes down to 22 meters, and there is the usual ups and downs.

So, there is a lot of "yo-yo" diving or what you call "bounce diving." It is normal in caves (you do not get square profiles).

What surprises me is that you find it so strange to do these type of profiles... maybe the caves you are used to are just like the sea with no ups and downs?

What also surprises me is that you find it strange using 70 bar from each of the two 18 ltr. side-mount tanks (exiting the cave with 150 bar of gas in EACH tank as I did on that dive, very conservatively).

My certifications (a small portion is in my profile on Scubaboard).

Also, quite strange that you find it so unreal that one can do a dive without a Dive Computer or Tables where a deco situation is impossible to achieve given the amount of gas that is being carried AND depth is known.

You seem more a PADI OC diver than a Cave Diver as you seem a bit incredulous that a dive like this can be done and caves like this exist (there are several).