Modified Thirds, Turn-Around Pressure and Lost Buddy Search SPG Calculations.

[Pullmyfinger]

I understand how you must feel. I may not agree with how you are going about it.
But I can see why you are frustrated about it.

Cheers,
Mitch

 

[Kevrumbo]

I understand how you must feel. I may not agree with how you are going about it.
But I can see why you are frustrated about it.

Cheers,
Mitch

Yeah you know Mitch . . .a person can only take so much before becoming "a little vindictive" !

And it was PfcAJ's feigned "bored indifference" in Post#8 --that was the "straw". . .

But there are worse slights, falsehoods/half truths & outright insults posted by others over the years in direct & implied inference to my DCS accident now over four years ago, including from people here on ScubaBoard that I once respected and learned a lot from. But that's okay, I've been motivated to learn & accomplish even more about handling the hazards of remote location technical wreck diving because of that abuse --and am planning another consecutive trip to Truk Lagoon this July, right after my first ever visit to the wrecks of Bikini Atoll. . .

 

[Pullmyfinger]

I do remember after reading about your incident, seeing other negative references thrown your way about it. That does kind of suck, because it must be humbling to post your own incident so publicly and then have people throwing jabs at you for a long time afterward.

* try not to let it make you too negative. ;-)

I recall Tortuga68 posting something a long time ago about deep dives, and I seem to remember him catching a lot of flak about it.

I like reading about what other people are doing in different parts of the world, so I get a lot out of posts like yours, as well as Tortuga68's.

I learned a lot about Tobin's incident as well. We all stand to learn something form all of these posts.

I have been to Chuuk once, and will return again after I get more training and can explore some of the wrecks that were out of my range before.
Interesting that you mention Bikini; it is also on my list of dream trips. While I am living in this part of the world I want to take a liveaboard trip to Bikini.

I will be taking rebreather training after my next work trip (a Carrier from July to October).

Then I will evaluate the Micronesian wreck diving trips from that perspective.

Until then....take care. Enjoy your trips! I am looking forward to reading about them.

I do have to say that I'm a "Kevrumbo hater"........I am totally envious about your Bikini Atoll trip.

Cheers,
Mitch

 

[Kevrumbo]

Thanks Mitch. And the best & friendliest GUE Diver teammates in the world are there in SE Asia/Oceania where you are and at Tech Asia Puerto Galera. The best practical wreck training is there and at Subic Bay Philippines.
--------
Back on topic, here's another example of gas planning on-the-fly, and easier to do quickly in your head because of the metric system:

. . .Just the physical exertion, pulling yourself along the surface with 11L doubles with 11L & 9L deco bottles clipped on, and then down another 5min of pulling hard hand-over-hand on the downline to depth at 48m was enough to blow through 50bar of expensive 21/35 trimix backgas. We thought about bringing an extra stage bottle each of bottom gas to offset this, but decided not to use it fearing our limited supply & unreliable transport delivery of helium would not last us through the week. Visibility was variable with initial good clarity in the first 15m, but would start getting hazy going deeper, and then beyond 33m the ambient light conditions would darken considerably as the wreck came into view. At 48m, shielded from the current in the lee of Hermes’ hull, the viz range varied as much as 3m to 9m in very dark murky water.

The dive planning tactics and strategy that developed over the first couple of days involved taking 50bar right out of backgas calculations all together due to fighting the current as described above. Setting aside a MGR (Minimum Gas Reserve) of 70bar in backgas, meant we only had 80bar out of a total of 200bar backgas to explore the wreck externally. Internal explorations used the modified rule of thirds –take one-third of 80bar, and you get 26bar delta turn pressure-- which at an average depth of 48m translates to 5min penetration time, possibly 10min if you can somehow recover and slow your breathing rate down after working hard descending hand-over-hand on the downline. Typically, I would get to the entryway with 150bar reading, and turn the penetration after 5min and 125bar showing on the SPG, but as the week progressed, I was approaching 10min and turning it around at 120bar as we became more physically “acclimated” and familiar with navigating our temporary main line. . .

Aircraft Carrier HMS Hermes Short History & Dive Report

 

[Tortuga68]

No Tortuga . . .explain an Excel Spreadsheet to anyone who doesn't even have basic computer keyboard skills -it will take 1000 words to just to set up and sum a column:

I think you're confusing explaining something with writing an instruction manual. The concept of diving modified thirds in metric is pretty simple, people in this forum get it.

I recall Tortuga68 posting something a long time ago about deep dives, and I seem to remember him catching a lot of flak about it

There were three threads actually and I tried not to take anything that was said too seriously

 

[Kevrumbo]

I think you're confusing explaining something with writing an instruction manual. The concept of diving modified thirds in metric is pretty simple, people in this forum get it.

Tortuga, to explain a "concept", sometimes you have to describe the methodology. Have you ever programmed a computer? You make a general outline of the operation you want to do, and then you sit down and type out the code "instructions".

I think you're confusing Deductive vs. Inductive Reasoning. . .

 

[Superlyte27]

Is this thread still going on? Geesh. We get it. Metric is better, DIR Peeps suck because they hurt your feelings 18 years ago. Move on.

 

[Kevrumbo]

For a planned penetration at 51m depth within the hangar deck of the 888’/270m long USS Saratoga Aircraft Carrier Wreck at Bikini Atoll, I’ll be using several 11L stage cylinders that will either be strategically placed along a reel guideline, or dropped after a prescribed gas consumption of 90bar (slightly more than half remaining -110bar SPG reading- in the 11L Stage). I figure that three dropped 11L stages will be the limit for the push inside –any greater linear distance farther will risk not having enough Out-of-Gas Contingency/Gas Sharing Reserve to egress on twin 11L Backgas Cylinders alone (i.e. not finding the dropped Stage Cylinders because of a silt-out for instance).

Minimum Gas Reserve/Rock Bottom to reach the 21m EANx50 Deco Stop in Open Water figures to be 115bar, so an emergency out-of-gas sharing buddy team better have found and consumed at least two 11L stage cylinders inside the wreck on egress, or else there better be a third teammate as well as other divers on the outside of the wreck to assist & donate gas.

 

[Kevrumbo]

Is this thread still going on? Geesh. We get it. Metric is better, DIR Peeps suck because they hurt your feelings 18 years ago. Move on.

I've been back to Truk every year -sometimes multiple visits per year- since that DCS accident over four years ago, with taunts from even Moderaters on this Board expecting "another train wreck in Truk" ('Moderhaters' like Lamont & NWgratefulDiver -uh-huh, flame on! Calling y'all bitches out now!), and have had no recurrence at all.

I'm going again in one month right after a first ever visit to the atomic wrecks of Bikini Atoll.

So yeah troll "move on" yourself. . .

 

[ajduplessis]

I hope Karma stays home