Callin major BS

I was watching a show called Wild Pacific this morning, and these guy's dive plan was to dive to 190' to collect a sample of coral from that depth. Then they giant strided off the boat with what looked like a single AL80 strapped on. No Nitrox, extra bottles or other gases evident. Then they descended to "190 ft".
They collected the sample and the narrator said they "hurried back up" to give the researcher the sample they'd collected. They didn't show any stage bottles or decompression stops. They just showed them getting back on the boat.
Now, I'm no deep diver. Deepest I've ever been was to about 90 ft in Cozumel.
Is it even possible to go down to 190 ft and return to the surface with just one bottle of air, let alone spend 10 minutes down there hammering a piece of coral loose?
Second of all, will coral even grow at 190 ft?

a) Yes coral will grow at 190 feet... even deeper
2) Yes it COULD be done on a single 80, but you'd have to work fast.

I'm sure a lot of people will say it's not safe, and really, it's not that safe. There's no room for error, and the desire to complete the mission could easily make someone overstay the bottom time, and the deco would rack up quickly. However, with a direct descent to 190 for 5-6 minutes of actual bottom time. The deco obligation is minimal, and the dive COULD be completed with gas to spare.

While they may not have shown any deco stops. There should have been a few 1 minute stops along the way, with a few minutes at 20 and then a few more at 10 feet. This could have been edited out through the magic of television (who wants to watch a deco stop on TV?)

You "can" dive to 190' on a single AL80, but the chances of running OOA or having a problem are extremely high, and you sure don't "hurry back up" to the surface!

I bet they had spare airs, so they were safe

LetterBoy:

I bet they had spare airs, so they were safe

Spoiler

Click to expand...

May they rest in peace. :blessing:

Up here where I live there's a red gorgonian that grows at depths much deeper than 190 fsw.

There's also a wall where young men sometimes attempt to prove their manhood by diving to depths below 200 fsw on single tanks ... usually AL80's. Most of the time they make it. One of my friends died on that wall trying such a dive a couple years back ... they found his body sticking out of the mud at 205 fsw about 10 months later.

Yeah, it can be done ... although I wouldn't believe they could stay at depth for 10 minutes on a single AL80 and make it back with gas in their tanks ... 10 minutes at 190 fsw incurs a significant deco obligation. Here's what the dive plan would look like on V-Planner ...

Dec to 190ft (6) Air 30ft/min descent.
Level 190ft 3:40 (10) Air 1.42 ppO2, 190ft ead
Asc to 50ft (14) Air -30ft/min ascent.
Stop at 50ft 1:20 (16) Air 0.53 ppO2, 50ft ead
Stop at 40ft 2:00 (18) Air 0.46 ppO2, 40ft ead
Stop at 30ft 2:00 (20) Air 0.40 ppO2, 30ft ead
Stop at 20ft 4:00 (24) Air 0.34 ppO2, 20ft ead
Stop at 10ft 6:00 (30) Air 0.27 ppO2, 10ft ead
Surface (30) Air -30ft/min ascent.

That's an awful long time on an AL80 ... you'd have to have the air consumption of a squirrel to pull it off.

Also keep in mind this was for a TV show ... they could easily have had (and probably did have) hang bottles at various depths for use by the divers if they should need it.

There's a big difference between what's possible and what's prudent. Only you can decide which matters more to you ...

... Bob (Grateful Diver)

.....

LetterBoy:

I bet they had spare airs, so they were safe

Click to expand...

Didn't see any spare airs. And they both had short primary hoses...

My NAUI chart maxes out at 8 minutes @ 130 ft. Anything deeper and I have to deco for five minutes @ 15'. Do the Navy charts show NDLs for deeper dives than this? (Not that I'd ever be interested in trying...)

I'm sure they had stage bottles and they were just editing for the sake of brevity, but the way they described it was that it was important to deliver the specimen as fast as they could. But if I were the producer, I'd know that there would be a good chance that divers would watch the show, so I'd be a little more thorough explaining the nuances of the dive.

short hoses and they didnt die?!?!?!?!?!?!?

What type/kind of Coral is to be found at 190' that isn't also at 70' ?