Info The Rule of 120

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Searcaigh

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1656825295558.png
Looks like he had gills too
 

Ucarkus

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Few thoughts:
Steve was not Persian but Assyrian and he was not diving but swimming with a float. And Bronze Age ended bc 1200. So, this could be perhaps 3k years ago..
I can’t relate to those rules because I am thinking metric. I have been teaching RDP enough times that most of the ndl is permanently established in my memory. I suspect anyone who actually dived with RDP in the past to a certain frequency is feeling the same way perhaps?
Average depth rule works but I never owned a dc that shows my current average, at least in DC mode; my Garmin does have the average for Gauge mode only. So, practically not so useful.
 

Manatee Diver

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Average depth rule works but I never owned a dc that shows my current average, at least in DC mode; my Garmin does have the average for Gauge mode only. So, practically not so useful.

May I introduce to our lord and savior Shearwater?
 

EFX

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Few thoughts:
Steve was not Persian but Assyrian and he was not diving but swimming with a float.
It looks like he's breathing from a tube extending up from the goat bag. If that's the case, why is he breathing from a bag if he is just floating on the surface?
 

EFX

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That’s a dumb comment. I’ve been bent more times than you can imagine. Mostly sub clinical dcs or skin bends. Some minor visual disturbances. I was also dead ass tired after every dive. As my dives progressed and skin bends got a little worse (meaning I couldn’t blame my drysuit for it he skin marks), I got tested for a pfo and was negative. Kept diving but got way more conservative and the dcs symptoms occurred less. 6 years later I was able to find a cardiologist who could actually locate the pfo. It’s been fixed and now after dives I feel invigorated. So much that I annoy my wife.
I will counter oya’s response to you with this opinion. You’ve likely been around someone with dcs or even had it yourself. The problem is it’s often sub clinical.
I'm sorry you had to go through so much trouble before finally finding the cause, but what has this got to do with my comment specifically, and what we're discussing in this thread in general? The question is whether average depth and/or the modified rule of 130 is safer as a backup to diving with a DC and backup DC.

At any rate, arguing from an exception (pfo) is not convincing. It's a logical fallacy called the missing middle.
 

Dan

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It looks like he's breathing from a tube extending up from the goat bag. If that's the case, why is he breathing from a bag if he is just floating on the surface?
The guy below him is not breathing from a bag. May be the bag is just half full of freshwater & air with siphon. He use the siphon to seep the water and blow air into the bag to control the buoyancy when he carries heavy catch?
 

boulderjohn

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It does not take a long Internet search to see that the picture is routinely believed to depict the use of inflation to assist in swimming, something that was apparently a reasonably common practice in many parts of the ancient world.
 

oya

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arguing from an exception (pfo) is not convincing. It's a logical fallacy called the missing middle.

This exception… a solid quarter of the population have a PFO. Which means one in four divers have one. A minority… sure… but a pretty strong one.

The vast majority of them don’t cause problems. Staynong class to No deco limits obviously helps. Hydration. Not jumping right into the hot tub after a dive. Lots of stuff helps.

But the point cuz was trying to make is that just because there are no symptoms doesn’t mean DCS doesn’t exist. It’s simply sun-clinical.

The point I was trying to make is that when people are afraid they’re going to be treated like idiots who obviously messed up to deserve to get DCS, they’re less likely to come forward to talk about symptoms and seek treatment. These are usually people who already scared and in denial. Stigmatizing them on top of that is laughing at someone who just broke their ankle taking a bad stair.

I personally know no fewer than four people who have had PFO. I know a couple of others who just started getting random DCS hits even during no-deco dives but tested negative for a PFO. They just… keep getting bent. One of them a well-known and deservedly well-regarded instructor who had to walk away from their career.

In any case: back to the whole question…
I always dive with two computers. I don’t surface until they’re both clear. It seems the point most people are missing is that I use the 130 thing as a subsidiary tool during dives, not in place of dive planning. And while I’ve tried to explain why it is quite useful to the type of diving I’m doing, I’m either not explaining it properly, or folks are having a hard time understanding the diving I’m doing.

But the thing I’m finding particularly perplexing is that I’ve said over and over and over that while I use the 130 the way I use it, average depth and all… it always comes out to, if not the exact same as my computer, then within a minute or two.

So for all the fact that I am, apparently, a complete moron who doesn’t understand anything about decompression theory… every single time I compare the results of the very simple subtraction I’ve done in my head to the final dive time of the very complex calculations my computer has made using 10second sampling of the actual ambient pressure over the entire dive…

It winds up being the same number.
 

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