From: mayne@open.cs.fsu.edu (William Mayne)
Newsgroups: rec.scuba
Subject: Re: Octopus Ergonomics
Date: 7 Apr 92 15:38:49 GMT
Article-I.D.: mailer.1992Apr7.113849.22088
Reply-To: mayne@cs.fsu.edu
Organization: Florida State University Dept. of Computer Science

In article <1992Apr7.051333.18580@scifi.uucp> njs@scifi.uucp (Nicholas J. Simicich) writes:
>
>I don't know of any agency that specifically advocates this.  Can
>anyone fill this in?  As far as I know, the big controversey is 'pass
>the primary' vs. pass the secondary.  Some agencies teach 'Pass the
>secondary' (PADI) some teach 'pass the primary' (SSI) and some leave
>it up to the instructor (NAUI).  

My PADI instructors taught 'pass the primary'. Has PADI policy changed
recently?

>Agencies or instructors that teach pass the primary typically advocate
>octopus mountings which specifically make it easier for the diver to
>recover their octopus...

A easy way to set up and carry the octopus so you don't even have to
recover it is to rig a neck band. Take enough rubber surgical tubing
to make a loop which will fit over your head, with enough to pass
one end over and one end under the second stage just in front of
the mouth piece, where the mouth piece itself attaches to the
regulator. Secure each end to the tubing coming from the
other direction with a plastic cable tie. This holds the octopus
right at your throat, where it shouldn't snag on anything. With
practice and the right setup you can reach down and pick it up
with your mouth, not even using your hands. If you do get into a
situation where you want to pass it anyway it can be pulled out of
the neck band. Don't make the attachment of the neck band to the
second stage so tight you rish pulling the mouthpiece off if you
have to do this.

>And I know of one 'pass the secondary' person who uses a left side
>reversed octopus, because it is easier to pass to a student.  He is a
>long time instructor.

And later Nick adds:

>Solve the whole problem.  Purchase a Poseidon regulator.  The second
>stage doesn't have a top or a bottom.

I agree. An ambidextrous side exhaust second stage such as a Poseidon
or an Oceanic Omega II (a.k.a. "poor man's Poseidon") are better for
passing either way. Perhaps my instructors taught 'pass the primary'
because they used Omega IIs as primaries. Omega IIs free flow too
easily to be good as secondaries. I wouldn't buy another one.

>>...but how often do you use your own
>>octopus?  If you're out of air, it's no help, and most second-stage
>>failures are likely to be free-flow failures rather than freeze-ups,
>>right?

There is no excuse for being out of air, unless you have had
a catastrophic equipment failure, which is more likely if you
have an octopus.

I consider an octopus a liability. Having it increases the risk of a
second stage free flow problem (more than double, usually, since the
octopus is more likely to get dragged in the sand and not to be watched
and checked as carefully). And if you have a first stage problem you'll
lose air faster with two second stages. When I didn't have so many
regulators if I got to an open water dive site and found an octopus
leaking I'd curse, plug the port, and go ahead and dive. (Asbestos dry
suit on.)

Even now in shallow open water I sometimes don't consider it worth the
regulator swapping I'd have to do to rig an octopus. My regulators are
normally set up with one second stage per first stage. I figure
if I need two second stages I need an independent first stage for each.
Only then does the secondary provide more safety than the problems it is
likely to cause.

The bottom line for me: The usual octopus setup, with one first stage,
makes it easier to deal with some problems, but it also makes problems
more likely to occur. That isn't always a good trade off.

>Us pass the primary folks believe that your secondary is for you, and
>your primary is for your buddy.

Whether you pass the secondary or pass the primary the reason to have
two second stages on the same first stage is for your partner, not
yourself.

Bill Mayne