Close Call on the SC Coast

[gcbryan]

...
What, if any, is the effect of breathing a whole tank in 10 mins vs. breathing a whole tank in 25 mins? In other words, is there a relationship between how much gas you breathe and how much you absorb?

No relationship...it's simply a function of time and depth.

 

[rockjock3]

Maybe the O2 bottle on dive boats should be yellow, have a normal regulator and just say: "MOD 12'" so the "Bob"s of the world can look like one of the "cool kids" and say he's "Finishing his deco on the surface."

Terry

Or "MOD 20". He still would look cool.

 

[vladimir]

2. How did Bob not get the bends if he came up from 96 feet in about 1 minute?

There is some safety margin built into the dive tables. I would not expect somebody with a minimal nitrogen load who ascended at 96 feet per minute to get bent. But I wouldn't be surprised if they were, either.

 

[TSandM]

Nitrogen absorption is not changed by your respiratory rate. Nitrogen equilibrates with the blood based on the respective gas tensions. You CAN end up with some more nitrogen delivery to tissues if you are working hard, which is why tables suggest that dives with exertion be considered as ten feet deeper than actual. Nonetheless, from the sound of this, he wasn't down long enough to absorb much nitrogen, especially into anything but the very fastest compartments (which are thought to tolerate higher overpressure gradients).

It sounds as though you tried to do everything that should have been done to prevent this mess. You had a dive plan, had a buddy separation plan, and tried to do an equipment check. You dove according to your plan, and assisted your buddy when he ran into trouble. I think I would have done the second dive (without "Bob", though . . . )

Stories like these make me glad that I have never had to do an expensive charter dive without a home-grown buddy. Wouldn't it be a great world if everybody you ran into on a boat had good personal skills, made and stuck to a plan, did buddy checks, dived to stay found, and had some idea of gas management?

 

[Web Monkey]

Or "MOD 20". He still would look cool.

As dumb as it sounds, for the cost of a tank and reg, I'm wondering if that wouldn't actually make O2 more socially acceptable. The green or silver "medical" bottle with the "hospital-looking" mask makes it the user look like a victim. A shiny chrome second stage on a yellow bottle with a stage strap and an MOD label looks "tech"

Maybe someone else could start sucking on it, proclaim they feel "wonderful" then offer it to a "Bob"?

Terry

 

[wvjohn]

thanks for the answers to my question!

As to the O2 bottle, howsabout "VITAMIN AIR" ...lol

 

[hueydok]

JWC3 - I live in Raleigh and dive the NC coast several times a month and would like to extend an offer to dive with you sometime in the near future. I agree that you did everything right (except for not having an experienced buddy!), and in particular I give you kudos for NOT letting go of the descent line to drop down freely after Bob. No matter who is your buddy, you must never place yourself at risk over someone else's foolish actions. In fact, you should ask yourself - if Bob was NOT waiting at the anchor, what would you have done? Hopefully spent a minute there and then ascend to report a missing diver (and your ascent should have been slower than 30 fpm and performed your safety stop).

Anyway - NC/SC coastal diving is the best (and worst?) diving in the world, and I encourage you to hook up with one of us local Raleigh guys (or gals) and enjoy a safe, comfortable, planned dive in otherwise crazy waters!

P.S. - Diving this weekend on private 6 pack out of Morehead City - hoping for the Atlas and the Caribsea if the weather holds!

 

[openmindOW]

JWC3 - I live in Raleigh and dive the NC coast several times a month and would like to extend an offer to dive with you sometime in the near future.

That's a nice offer. There are some good people in the dive community.