All

For once, I don't necessarily agree with, but have some sympathy for, what
John Grogan says.  However, the AP Valves manual inflate DSMBs he recommends
are just fine and the recently reported auto fill variant of them sounds
perfect, being the best of both worlds.

I carry my Advanced Diving Products DSMB in a  small pouch which I keep next
to my canister light and held in place by the same weight belt buckle.  The
pouch sits under my arm on my hip and out of the drag and snag.  I've sewn a
dart into the pouch to make it easy to remove the DSMB as I had it
embarrassingly stuck once (thanks Kevin).  The dart makes the pouch more of
a V-shape and hence easier to remove the DSMB.  This pouch will restrict the
DSMBs inflation should it occur by accident and will also prevent it
flapping in the breeze as John mentions can be the case were you to butt
mount it for example.  The main disadvantage with self inflate DSMBs are
their bulk, apart from that they are a joy to deploy.

Anyway, I thought I'd pass on a tip WRT SMBs in general.  Sausage SMBs tend
to sink and rise I waves more effectively than the round or pear-shaped
variants which pull on your arm as a wave goes over head, especially the
foamy variety of waves so common in UK waters :-(. As I have a pear shaped
DSMB, I have inserted a short shock cord on my reel to reduce the pull on my
arm and make deco more comfortable.  The shock cord is a thin bungee about
0.3-0.5m long.  The trick is NOT to cut your reel line.  Instead, tie one
end of the bungee to the line near the clip.  Coil the line around the
length of the bungee until you reach the other end of the bungee.  Then tie
another knot.  The bungee should be able to be stretched to its fullest
extent without the coiled line becoming taut.  If the knot slips or the
bungee breaks, you still have your line connected to the SMB.

BTW, the bungee and knot should be small enough to be wound onto your reel
and short enough to be able to be pulled fully out from your reel before
deployment.  This avoids reel snags as we don't want this sort of excitement
on a dive!

Enjoy.

David Shimell
Project Manager, Sequent Computer Systems Ltd., Sandton, South Africa (but
currently in Milan Italy).
Email: shimell@se*.co* <mailto:shimell@se*.co*> 

-----Original Message-----
From:	Peter Fjelsten [SMTP:fjelsten@ma*.st*.dk*]
Sent:	Friday, April 30, 1999 1:58 PM
To:	John Grogan
Cc:	techdiver@aquanaut.com
Subject:	Re: Auto inflate smbs

John Grogan sendte noget til mig den 11:59 30-04-99  som indeholdt praecis .

... .
The week link in the chain is the diver and it relies too much on the diver
to remember to do a number of things.  All it takes is to forget 1 thing 
and it's useless.  You then have to resort to your backup D-SMB which most
likely is one you fill from your reg, so why not cut out the first
problematic stage.  Again, rather than create more problems in order to
solve one, just avoid the original problem in the first place.

- As I said, my primary reason for using the integrated type is to prevent 
freezing. I am completely aware of the 'patching of other problems' issue, 
but I use the cylinder type to prevent a real problem from happening (reg. 
freezing). I'm not saying that this is the _only_ way to do it and I have 
contempleted going back to the original type buoy but the freezing issue 
troubles me somewhat. How cold do the UK waters get? To the best of my 
knowledge you are constantly 5-10 degrees over us?

- "The week (sic) link in the chain is the diver": One can forget many 
things. If one can forget to fill the buoy cylinder it should - 
theoretically - be just as easy to forget filling your deco cylinders? I 
know that this is ridiculous but do you see my point? And only thing must 
be remembered: to fill the cylinder. The diver must remember to do a lot of 
things before he/she is ready: get the equiment ready, cut tables, fill 
cylinders, etc.

Again, another thing to bring with you.  Another weak link in the chain and
this doesn't solve the occasions when you forget to fill the bottle.

- If I can/must remember 100s of other things: the O2 analyser, analysing 
my gas, my fins (not 'analysing my fins' :-), etc., ONE extra thing 
probably won't make the whole system collapse. Some people have to remember 
to bring a lot more stuff than I, so I think it's within my mental 
capability to remember this.

So had mine but the effort of jumping from the back of the boat into the
water undid the velcro on about 70% of dives.  I always got to the bottom
only to discover it had un-done.

- Mine has never come undone in my 2 years of use.

I suspect that in entering the wreck, the valve somehow got partly turned 
on and it slowly filled the bag.  If your bottle has a valve, then it can
happen to you too.  Just because it hasn't happened yet doesn't mean it
won't ever happen.

- I think that there is a difference between buoys and how you carry them. 
I suppose you used the ADP? How did you carry it?

Since I ditched mine, I became more observent of others using them and I've
found that those people tend to use them because they cannot properly use a
D-SMB without a bottle.  In other words, they cannot send up a bag without
losing their buoyancy, or without free-flowing their regs or without
tangling up the line or screwing up in some other manner.  It's often a 
poor substitute for skills.

- I used a regular DSMB for some time before getting this type. Yes, I can 
do it with a regular type so I - alas (?) - do not fit in your "lack of 
skill so get a cylinder DSMB" group.

- As I stated above, I am not totally opposing the non-cylinder type and 
sometimes wonder whether I should switch back, so I am _not_ claiming _my_ 
way necessarily is the best/only way. Convince me!

Hilsen (Rgds.),
	
Peter Fjelsten
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