From: gd@gehenna.sw.stratus.com (Greg Dawe)
Newsgroups: rec.scuba
Subject: Re: Helmet-mounted dive lights
Date: 6 Nov 92 16:07:45 GMT
Organization: Stratus Computer, Software Engineering

In article <1992Nov5.131125.20771@cattnts.canada.ncr.com> craig@cattnts.canada.ncr.com (Craig Campbell) writes:
>In article <7833@transfer.stratus.com> gd@blublaze.sw.stratus.com (Greg Dawe) writes:

>As a slight asside, do you carry a spare mask?  If so, how would you change
>masks during a dive if your mask strap is inside your hood?
>
An interesting question which I've only recently begun to think about.  I've
never carried a spare mask, but I'm taking a TRIMIX class which requires it.  
Before I tell what I think I'm going to do about the spare mask let me say 
why I wear my mask strap inside the hood.

Wearing the mask strap inside the hood has many advantages and disadvantages.
On the plus side the mask can't be knocked off your face during a backwards
roll - or by a panicked diver during a surface or submerged rescue.  Sure, it
can be displaced and unseated, but not knocked-off completely.  So it can be
argued to a small degree that a spare mask isn't needed it you can't lose 
the one you're wearing.  Also, tucking in the strap is an easy way of 
eliminating a nasty monofilament trap on the sides of your head (yeah, I know
I could tape them, so this is really a minor point).  On the down side, you 
cool-off MUCH faster, because more water gets let into the hood.  This can be 
uncomfortable during long hangs.  If you've got a dry hood, like from say a 
Viking suit, tucking in the mask isn't an option unless you wear another (wet)
hood on the top with the mask in between (sounds like overkill, but I've seen 
divers do it).  

Since I'll be forced to carry a spare mask during this mix class I won't wear
the straps of my primary inside the hood.  Actually, I suspect that because of
the deep depths required for TRIMIX hangs I would get too cold if the straps
were inside - not to mention the added complications and chills when going thru
the drill of switching masks at depth.

>I have a similar problem with wearing a helmet and mits.  My compromise is 
>to only do half of the strap up on the helmet, so I can easily grab the loose
>end and get the helmet off if I have to.  With the strap fully done up, I 
>would never be able to get it off and put on my backup mask.
>
Excellent point - adding equipment always seems to complicate emergency drills.
I make a point of putting time up-front with new gear in a pool, and then a
shallow divesite to retrain myself so that I react properly to any kind of
unusual or emergency situation.

BTW, I'm considering wearing my spare mask around my neck, with the mask
facing backwards, but I haven't tried this out yet.  I can see the primary 
disadvantage in that you've got to take the second stage out of your mouth
before you seat the mask - something that may prove to be unadvised, but I'm
going to try it out first.  Where do you carry your spare?  Many of my partners
are cave certified, and they carry their spare in various places, like over the
top of a battery pack etc - configurations that seem appropriate to the cave
environment, but not so good in open water where they might be knocked off.
I've yet to see a carrying place as secure as around the neck (BC pockets
aren't an option, since none of us have any).

-- 
Greg Dawe                        | Disclaimer: I don't speak for my employer,
Voice : (508)-490-6666           |             nor they for me...
e-mail: Greg_Dawe@vos.stratus.com|