Re: On board fires

[shawl@torchlake.com (Jonathan Shawl)]

In item # "12. Always carry a fire extinguisher of the dry chemical type,
securely mounted and immediately available."
My question is what kind of gas is used as the propellant?
I hope it's not CO2 or anything toxic. Wouldn't that be bad in a confined space.
Since subs have low voltage electrical systems, what about a water spray type fire
extinguisher?
Jon Shawl

VBra676539@aol.com wrote:

> Ray,
>
>         I would like to add a few thoughts about fire protection and strong
> fire defenses to what I wrote this morning.  Some is obvious, and the
> operational psubbers will have sussed most of this out already no doubt, but
> folks still designing may see something they hadn't thought of.  Most is
> common sense--some good practices from my favorite E.T.s at work--and one or
> two things that made a difference for me when the smoke started leaking out.
>         Here goes:
>
>         1.  DO NOT use crimp fittings in your electrical system!  They
> corrode, arc and become hot spots over time.  Time bombs, one and all.
> Solder ALL connections, including the lugs you use to connect stuff.  Don't
> let the salesmen of the world talk you into crimping ANYTHING.  Get rid of
> the crimping pliers you now have and buy a good soldering iron.  Learn to use
> it.  Then use it.  Every time.  And always use shrink tubing, shrink wrap or
> shrink tape over the solder joints and then the black sealant goop they sell
> to paint over the shrink (shrunk?) wrapped joint.
>
>         2.  DO NOT splice wire unnecessarily.  Use the correct length to
> start with, and plan it so that the wiring harness is neat and tidily
> bundled.  Ty Merritt used to tell me that if it LOOKS good, then it will work
> better.  It might be an emotional response but tangles and knots of wire look
> like hell and are ripe for shorts and crossover hot spots.
>
>         3.  Size your wire according to load, and use pre-tinned, flexible
> wire, not drawn copper or aluminum.
>
>         4.  Use spade or blade or ring lugs for all connections (and solder
> every one and shrink wrap it and goop it).  Yeah, I said that already.  It's
> important.
>
>         5.  Use explosive-atmosphere grade switches (sealed from the
> atmosphere).  Breakers, fuses and fuse links should be sealed so that arcing
> occurs WITHIN the unit, not in the psub's potentially oxygen rich environment.
>
>         6.  Arrange your power distribution in a box of some sort (preferably
> sealed) so that insulation fires or hot wires will starve out as soon as the
> electricity goes away.
>
>         7.  Fuse or breaker your battery bank(s) so that a short circuit in
> the bank itself will be self-isolating (one hopes!).
>
>         8.  Pay strict attention to the materials going into the crew
> compartment of your psub.  Fire proof and fire retardant materials should be
> used whenever possible, including your paint.  The question to ask of each
> material is:  Will this give off particulate irritants, organic poisons,
> plastic toxins .... ?  Query the manufacturer for potential toxins and
> irritants of their products and then try to imagine sitting in there dealing
> with it.  (This can be very instructive, as imaginary fires can be pretty
> damned scary, too!).
>
>         9.  Design a BIBBS (Built-In-Breathing-System) into your air
> distribution system (not the oxygen system, this will be isolated immediately
> a fire is suspected).
>
>         10. Be sure your built in cabin pressure/vacuum relief is above the
> waterline but easily reached and readily available so that you can equalize
> as you surface and have no pesky delays in getting the hell out of there.
>
>         11. Be vigilant.  Once you go operational and start diving, it is
> very easy to accumulate bits and pieces of this and that in the sub.  Rags,
> paper products, plastic cups and the like.  Watch out for flammables creeping
> in.  Add this kind of thing to your check sheets.  Keep your oxygen content
> at or slightly below 21%.  Keep your boat clean and clean up those hydraulic
> dribs and drabs that seem to accumulate no matter how careful you try to be.
>
>         12. Always carry a fire extinguisher of the dry chemical type,
> securely mounted and immediately available.
>
>         You may figure that planning all this stuff and practicing with the
> equipment and maintaining all the components is too much of a good thing.
> Until that first whiff of smoke, that is.  That's when it pays off.
>         Remember, be a good Scout and BE PREPARED.  Like the man said, there
> is simply no use at all in carrying a knife to a gun fight.  The right tools
> are required and when the gunfight happens there is never time to think about
> it.  You have to be ready to fight.  And just as importantly, you have to be
> PREPARED to fight, which isn't quite the same thing.
>
> Hope this helps,
> Vance
>
>