Review: The Last Dive

[Scuba_Steve]

Huh?

I'm talking about the book, the dives, and the conclusions of the writer and I guess yes to a point, what people take out of it as far as bettering their own diving, which I hope is very little because a lot of the conclusions of the author are nutty as peanut butter

Regards

 

[Don Burke]

i recall that his rationale was that the 17/35 wouldn't help him with deco at that depth

It most certainly would help in deco, just not very quickly.

.. i guess he wanted pure O2 to speed it up

He was at 40 feet. Pure O2 was not a good option.

i don't know too much about deco (actually, precious little), but i think if i had to chose between oxtox at 40 and DCS at 20 with pure O2 available (remember, the boat had an unlimited supply piped down to a regulator at 20 feet), i'd take the 100% O2 and DCS risk

I would have flattened the cylinders of 17/35 before coming up to 20 feet, unless something more suitable was delivered. Since the boat got air to the diver later, I suspect some 50% could have found its way down there before the 17/35 was exhausted. In any case, more time at 40 feet could only help.

especially so since 100% O2 is a great treatment for DCS, so you'd be killing two birds with one stone (doing deco and fighting DCS)

Getting bent to get treatment sooner does not strike me as a good idea. Avoiding DCS in the first place would be my plan.

 

[H2Andy]

hhmmm... well, i'll defer to your knowledge of decompression, since mine is
rather slim

i was looking at it from a logistics point of view. at 40 feet, he had a choice
between 17/35 and pure O2. neither was a good option. rather than staying
there, he ascended 20 feet and went to O2, which was a good option. i see
the danger of DCS as minimal here, particularly given the huge amount of time
he spent at 20 feet on pure O2

 

[Don Burke]

i was looking at it from a logistics point of view.

You have now lost me. How could the "logistics" be improved by swimming away from cylinders of 17/35? The oxygen would be at the same place either way.

at 40 feet, he had a choice between 17/35 and pure O2.

He had many more choices than that.

neither was a good option.

Staying on 17/35 was considerably better than ascending when he did.

rather than staying there, he ascended 20 feet and went to O2, which was a good option.

If, for some reason, he was forced to go to 20 feet, O2 would have been a good option. He was not forced, so the ascent itself and everything that stemmed from it was a bad option.

i see the danger of DCS as minimal here, particularly given the huge amount of time he spent at 20 feet on pure O2

There is a very good chance he was already bent when he got to 20 feet. "Bend and treat" is a very poor way of dealing with DCS.

For that matter, I would not rule out him being bent when he was at 40 feet. I will have to see if I can come up with a timeline for his dive and feed it to DecoPlanner.

 

[H2Andy]

You have now lost me. How could the "logistics" be improved by swimming away from cylinders of 17/35?

we keep going around in circles. you don't agree with me; that's fine. i just
don't want to repeat myself over and over again.

he had unlimitted O2 hanging from the boat; he chose to ascend 20 feet to
get to it. he accepted a small risk of DCS. even if he had been hit, it
was not a big deal as he had O2 available.

i don't think that's an unreasonable decision.

For that matter, I would not rule out him being bent when he was at 40 feet.

exactly... he knew that, and getting to 100% O2 quickly was of paramaunt
importance.

he could have stayed at 40 feet and risk an ox tox hit, or he could have gone
up to 20 feet and start the one unequivocally proven treatment outside of
a recompression chamber for DCS -- pure O2.

again, i think his choice was a rational one

 

[Don Burke]

i just don't want to repeat myself over and over again.

I would settle for you saying it once.

How does swimming away from cylinders of 17/35 improve the logistics?

he had unlimitted O2 hanging from the boat;

...which would have been there after he finished off the 17/35.

he chose to ascend 20 feet to
get to it.

...which was unwarranted.

he accepted a small risk of DCS.

actually, he added substantially to his risk of DCS.

even if he had been hit, it was not a big deal as he had O2 available.

The Rouses both died with O2 available.

i don't think that's an unreasonable decision.

The logic of that statement escapes me.

exactly... he knew that, and getting to 100% O2 quickly was of paramaunt
importance.

Actually recompression is of paramount importance in the treatment of DCS. He chose to ignore that, hence it was a bad call.

he could have stayed at 40 feet and risk an ox tox hit, or he could have gone
up to 20 feet and start the one unequivocally proven treatment outside of
a recompression chamber for DCS -- pure O2.

He left an environment compressed the point where he had no DCS symptoms to pursue what we agree is not as good as treatment under pressure. Bad call.

again, i think his choice was a rational one

That is why "The Last Dive" has limited training value. It perpetuates misconceptions.

 

[H2Andy]

lol ... i am well aware of your side of the argument, you've stated it several times.
i think you're going to have to come to terms with the fact that we disagree
on this one.

if i suspected i were bent, i'd go for 100% O2 even if that meant ascending
an additional 20 feet

simple as that

as for the logistics, think about it for a while. on one hand you have
unlimited O2 piped down; on the other, you have several tanks to mess
with, or, as has been proposed, various mixes of O2 being brought down
to you with tanks.

just simplifies things to go to 100% O2 at 20 feet and spend buttloads
of time there (as he did)

ideal? no. but of his choices (which i've already discussed three or four
times) that one was the best available.

 

[Don Burke]

just simplifies things to go to 100% O2 at 20 feet and spend buttloads of time there

That is a "bend and treat" technique, which may be the most damaging way available to deal with offgassing outside of "bend and ignore".

There is a price to be paid for getting bent and the diver we are talking about was pretty close to draining his account in that regard.

You are right. You will find it impossible to convince me that bending a diver just to avoid switching gasses is a good idea.

 

[H2Andy]

well, you yourself admitted he was probalby already bent at 40 feet.

i am sure that played into the equation. getting 100% pure O2 quickly
must have seemed like the right thing to do.

to a beginner like me, it certainly does, if i am at that point. hopefully, i'll
avoid the charlie foxtrot that led there ... i hope