Can someone analyze this incident please?

[Rescue Diver68]

I waited for her at 15 ft and she met up with me after my own safety stop was over and while I was only hanging there waiting for her. I could have exited the water but since I was only 15 ft I thought Id hang some more. At 15 ft, It takes a long time to exhaust a tank and even if it is exhausted you can break the surface with ease. It was not a near death experience by any means but I wantd to know what do other people do? Do you guys jut follow your computers and surface abandoning your buddies or do you stick with your buddy abandoning your computers?

I would wait for my buddy- air permitting. You ask for us to analyze and have gotten no less than that . Moving forward in your diving especially if you are diving off the coast of Va. as I assume this was. Rent or buy larger tanks and make sure you and your buddy have a plan prior to the dive. Thanks for sharing your experience and not being too insulted by the replies.

 

[Jax]

Hey, Sinbad;

Obviously there was a communication lacking . . .

Here's a possible answer - if she was diving a recent Uwatec with Position Dependent Intermediate Stop, and some level of conservatism greater than 0, she would have at least two stops you wouldn't have. In this case, since she didn't indicate a problem and had a bigger tank, you did what was right for you. It was good of you to keep an eye on her from the surface.

 

[USVet96]

One thing to remember IS the computers that BOTH of you are using. You should know ahead of time at least which kind of computer each has. This will help eliminate some issues right there.

For example: if one is using an Oceanic and the other is using a Suunto, knowing a little bit about the algorithms the computers use will let you know that the Suunto is a more "conservative" computer. That will have to be taken into account when you are doing your dive planning; otherwise when they have to come up, according to the computer (if using that solely and no gas management was done), you will still have more "time" remaining on your computer and may face a similar situation, or vis a vis with your computer and time.

It's important to try to cover as much of this as possible beforehand to avoid these situations, and why gas management and planning is so important.

 

[acrofrag]

Beat up? Yes. How can you not say he was? Threads like this make somebody not want to ask questions. Not all of us started at 1000 dives, though in a forum I suppose you can on a screen.

 

[Mr Carcharodon]

One thing to remember IS the computers that BOTH of you are using. You should know ahead of time at least which kind of computer each has. This will help eliminate some issues right there.

For example: if one is using an Oceanic and the other is using a Suunto, knowing a little bit about the algorithms the computers use will let you know that the Suunto is a more "conservative" computer. That will have to be taken into account when you are doing your dive planning; otherwise when they have to come up, according to the computer (if using that solely and no gas management was done), you will still have more "time" remaining on your computer and may face a similar situation, or vis a vis with your computer and time.

OK since you brought it up how much difference in bottom time and ascent time would you expect from an Oceanic and Suunto for this dive? If you do not know how are you going to do your gas plan?

I’d suggest unless you do not know what both computers are going to do before splashing you do not have a plan. And most people will not be able to predict what every other computer out there is going to do.

 

[Dive-aholic]

Sorry for the mistake folks. This was a recreational dive not a decompression dive. I did not violate the rule of the thirds but if I had made a point to stay with my buddy then it would have resulted in that violation. Sorry for the mistake. the correct word in this situation is a safety stop not decompression stop.

If you did not violate the rule of thirds, you would have surfaced with plenty of gas in your cylinder, even with the miscommunication that occurred. The rule of thirds dictates you use 1/3 of your gas to get down and away from the anchor line, turn around and use 1/3 to get back to the anchor line and ascend. The final 1/3 is used in cases of emergency. You state "then my tank started to run low as it was an AL 80 and we swam towards the end where the anchor line was." If you were diving thirds, you would have turned the dive and started swimming toward the anchor line when you reached 2000 psi (assuming you started with 3000 psi). You surfaced with so little air because you did not plan your dive and manage your gas properly. And even though you were assigned an insta-buddy, it's still your responsibility to discuss and plan the dive before you get in the water.

 

[DandyDon]

This is where the rule of thirds came into this thread, perhaps because he accidentally said Deco-stop when he meant Safety-stop...

Sounds like you massively violated thirds and did not have enough gas to do the dive safely.

There was no explanation for the term which may be new to him? Which agencies teach rule of thirds for recreational diving? See Rule of thirds (diving) - Wikipedia, the free encyclopedia

The rule of 3rds comes from cave diving. In non deco open water diving we don't normally follow it. The usual rule is to come up with around 700 psi. If you have to buddy breathe you can just skip the safety stop if low on air.

If you do follow the 3rd rule with a single tank, you'd turn back at more than 2000 psi which makes for very short dive.

Adam

Now we did clarify that he was not Deco diving as erroneously stated early here, so I think we can get off his back at any time now.

 

[CAPTAIN SINBAD]

If you did not violate the rule of thirds, you would have surfaced with plenty of gas in your cylinder, even with the miscommunication that occurred. The rule of thirds dictates you use 1/3 of your gas to get down and away from the anchor line, turn around and use 1/3 to get back to the anchor line and ascend. The final 1/3 is used in cases of emergency. You state "then my tank started to run low as it was an AL 80 and we swam towards the end where the anchor line was." If you were diving thirds, you would have turned the dive and started swimming toward the anchor line when you reached 2000 psi (assuming you started with 3000 psi). You surfaced with so little air because you did not plan your dive and manage your gas properly. And even though you were assigned an insta-buddy, it's still your responsibility to discuss and plan the dive before you get in the water.

You are correct. TSandM asked the same question. Let me explain what was happening.

I turned and headed back towards the rope while I had 1/3rd gas in my tank. This means I am moving towards the anchor line at 1000 psi as started the dive at 3000 psi. In my understanding, rule of thirds means when you reach 1000 psi you end the dive and go up! It does not mean that at reaching 1000 psi its now time to do deep stop at the same depth with the same air. But I realize that my buddy is doing a deep stop pretty much at the same depth at which we were diving. This causes hesitancy on my part to ascend. I waited for sometime, not knowing how long her stop would take. Hell I didnt even know it was a stop. I had no idea why she was not coming up. I do not recall how long I waited but that wait was causing me to go below 1000 psi on my tank. I chose to let her do her thing (whatever it was) and started to ascend. But I am confused if this is an ethical thing to do because it is my training to stick close to the buddy at all time. So I rise until my computer tells me to do my stops. This obviously is happening at depth different from her stop depth so this would be calld buddy separation. Once I finished my safety stop at approx 15 feet, I had the option of surfacing with 500 psi gas in my tank or staying on the rope as courtesy to my buddy who is inching up the rope. I chose to hang on the rope just so that the other person doesnt feel ditched. While doing this I am pushing below 500 psi but I dont care because I have fulfilled all my safety stop obligations and surface is only 15 feet away. After a very long wait I am joined at 15 feet by my buddy and we surface fairly close to each other. I am below 500 psi when I get out.

 

[fisheater]

The "rule" of thirds, is that you use only 1/3 of your gas on your way to your destination. You should use 1/3 to return and have 1/3 in reserve for contingencies.

Thus, under the "rule," you would return with 2/3's of a tank of gas, not 1/3.

 

[TSandM]

Well, the Suunto may be conservative, but that's only in terms of NDLs. It won't ask you for deep stops. Other computers may be more generous on NDLs but request a different ascent profile. And if you aren't using a computer at all, but are doing GUE MDLs, you will be expected to do stops starting at half maximal depth.

Again, all this should be discussed BEFORE you get in the water. Proactive beats reactive.