Octopus second-stage: over shoulder or under arm?

[CuzzA]

The diver said in the comments on YouTube, which I don't recommend anyone read as you'll lose a few brain cells, that he no longer could get gas from his reg. It appears to me that this incident happened at the end of the dive, as they didn't turn back and it looked like they weren't all that deep. So he probably didn't have much gas left anyway and perhaps the leak further reduced the pressure in the first stage to deliver enough cracking pressure to his second.

Looking at this video closer compels me to offer an analysis...

The video definitely illustrates a bunch of failures on the diver's decision making and gear choices resulting in a cluster f. The first donating diver. I'll call him Diver 2, throws his primary at the OOG diver (Diver 1) rather than handing it directly to him. It appears his primary is on a pretty short hose and since he's in front holding the line the hose is across Diver 2's face. They probably should have stopped and let him move in front, but nevertheless, they both had secured the breathing source and could have moved up the line and ended the dive... But here comes Diver 3. Like a bull in a China shop, he's hell bent on being the donating diver. Strong arms diver 2 off the line. Now the octo is free flowing and pulled out of Diver 1's mouth, he's floating away. Diver 1 has to grab him and get him back on the line. Diver 3 just had to use that back mounted pony, come hell or high water. Of course if he had the pony slung he could have just handed it off to Diver 1.

But wait. It gets better. Now Diver 1 has lost his air source. Grabs his dead reg and tries to breath off it. Meanwhile Diver 3 has since dropped the pony tank reg and now has to buddy breathe with Diver 1. Then, for whatever reason they decide Diver 2 should again be the donating diver, but with Diver 3 now in between.

Nothing makes sense here. Especially at the end when it appears they weren't more than ten feet deep and bolted to the surface in an instant.

They need a good dose of some dive training and some ScubaBoard advice. Diver 1 might have learned here that he could have just kinked his HP hose and stopped the leak.

 

[AfterDark]

Yes, the reading may be off. But switching off your primary doesn’t solve that. And there is no reason to just ‘give up’ on that gas. HP leaks are ‘slow’ and there could be a lot of usable gas in that cylinder.

Maintain contact with your buddy and make sure they know what’s going on. Have them verify their octo is operational (should have done this already) and use as much of your gas as you can.

This is one of the reasons I think it was staged, and why I asked if his SPG leaked all the way to the surface. You posted what I was hinting at. Also if that was real world then they are a very "confident" team. During all the CF not one of them looked concerned as far as one can make out. Very calm trio, need more discipline.

 

[Bubbles McGee]

That would imply a 360 degree swivel, as in the picture earlier in the thread, correct?

I use a 110 degree swivel similar to this.

 

[jadairiii]

... A 7 ft. hose doesn't make much sense in open water as its purpose is for single file cave exiting. ...

7' hose works great in any situation. It is a misconception that its just for single file cave exits. The 7' hose allows you to control the OOA diver regardless of position or location, and is stows away clean.

You have a diver that is beginning to panic, you will wish you had them on your 7' hose.

 

[CuzzA]

7' hose works great in any situation. It is a misconception that its just for single file cave exits. The 7' hose allows you to control the OOA diver regardless of position or location, and is stows away clean.

You have a diver that is beginning to panic, you will wish you had them on your 7' hose.

I have a 7ft. hose on my doubles rig. I have no desire to put one on my singles rig. If I'm sharing gas with a diver who begins to panic I want them close to me so I can get control of them and save their life. I don't want them 7 feet away from me before they bolt to the surface.

 

[Diver-Drex]

I have a couple of dives on the Vickery, there is heavy current and you are right on the edge of the shipping lane. But the wreck is a great example of how well wooden ships are preserved up there.

As bad as they looked I have trouble believing it was staged. It took three of them to share air poorly? I just don’t get it.

I also don’t believe the narrative that accompanies the video. A leaking hp hose takes some time to empty a tank. I saw 20 minutes to drain an 80 posted on SB. That’s 4cft/min. The diver is at 40’ or so, let’s call it 8cft/min. From what is shown in the video and in his narrative, he sees the leak and gets two breaths. That’s 10 seconds and the tank was empty. The math said he had a bout 1.5cft left when this incident started. I know exactly where they are in that clip, he was not going to make a normal ascent to the surface even without the leak. He also states that the third breath was “water.” That’s not what happens when you breathe a tank down.

So none of this really jives. Staged maybe, embellished certainly. But to what end? “Here’s a fake OOA and how not to handle it”? It doesn’t matter..:

 

[Manatee Diver]

A leaking hp hose takes some time to empty a tank. I saw 20 minutes to drain an 80 posted on SB. That’s 4cft/min. The diver is at 40’ or so, let’s call it 8cft/min.

A HP hose leak doesn't increase as depth increases, it is a constant leak regardless of depth.

 

[Diver-Drex]

A HP hose leak doesn't increase as depth increases, it is a constant leak regardless of depth.

Boyle’s Law

 

[Manatee Diver]

Boyle’s Law

Boyles law only affects LP leaks because the IP increases as you go deeper so that the volume of gas delivered is the same. HP hoses deliver air at tank pressure. So a complete HP hose failure will drain a tank in 22 minutes if happens at 10 meters or 50 meters.

 

[Diver-Drex]

Thanks. If that’s the case then the math is even worse. He empties the tank in 10 seconds at a rate of 4cft/minute. Which means he had about half a cubic at the start. Making this whole thing even less believable.