[fa.arms-d] Arms-Discussion Digest V0 #136

C70:arms-d (07/02/82)

>From HGA@MIT-MC Thu Jul  1 22:29:20 1982

Arms-Discussion Digest                            Volume 0 : Issue 136

Today's Topics:
                         Spare Parts & Maint
                     The Utility of Big Carriers
                             US defenses
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Date:     1 Jul 82 17:05:23-EDT (Thu)
From:     Earl Weaver (VLD/VMB) <earl@BRL>
Subject:  Spare Parts & Maint

These comments are to shed a little light on the spare
parts/maintenance problem the armed forces have.

First of all, the decision of what parts to keep for spares depends on
whether or not combat is involved.  Most of the data base for such
things is based upon peace time wearout.  We know how many hours an
aircraft engine is capable of functioning before it is considered
unsafe without overhaul.  Likewise we know how often to change oil and
change spark plugs, etc. (BTW, the average battle tank can go 6000
miles before a complete overhaul is needed.  The average soviet tank
cannot go as far before similar repair is needed; that is why they
haul their tanks around on tank carriers.) [I cannot site references
other than discussions with tankers and maintenance personnel whom I
believe because of their experience.]  I once heard that combat
commanders requisition spares based upon five times the normal
peacetime wearout.  Obviously, the problem with that approach is that
in combat, things not only wear out, but get shot off. Many components
of weapons systems really don't wear out, thus there is no need for
too many spares for such parts.  An other problem is that some parts
age; if stockpiled they'll just go to waste.

	The Army has been attemping to get a good handle on the spare
parts problem as well as the maintenance problem.  The sample is
relatively small for combat damage.  The Israeli conflicts have been
valuable (?!) in this regard since US M-60s were involved.  The
problem boils down to solving the problem: given a scenario in which
we expect some munition to be used against a set of given materiel,
what is the probability of damage to a specified part, given a hit.
Vulnerability analysis (analytical) is being used to attack the
problem, but the path is not simple.

	The maintenance problem is also related to vulnerability.
Unfortunately, ease of maintenance and the vulnerability of materiel
are related in that usually if a piece of equipment is easy to
maintain (repair) it is usually easy kill (or disable to the point of
not being able to complete its mission).  Design goals include
exercises of placing 'critical' components in positions such that they
are shielded by non-critical components; it is impractical to armor
every component in a weapon system--it would be so heavy it could not
move!  Thus, by making the materiel less vulnerable the penalty is
often a mechanic's nightmare.

	War machines are not like commercial vehicles [although from
some of the ones I've worked on you'd think the engineers placed
components expecting combat!].  The idea of bolting armor on a tank
sounds good, but in today's battle field, the armor would just get
blasted off (possibly by munitions that would otherwise not affect the
tank).  Blast and shock from high energy projectiles are really
destructive.  I saw a picture once of an M-48 tank that was hit in the
turret (without blowing it up) and the shock was so fierce the main
gun tube [those military types don't call it a barrel] broke off about
a foot out from the turret.

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Date:      1 Jul 82 14:36:51 EDT  (Thu)
From:     Steve Bellovin <smb.unc@UDel-Relay>
Subject:  Re:  The Utility of Big Carriers

What's the range of a modern anti-ship cruise missle?  300 miles?
Whatever the figure is, it's sure to improve dramatically in the near
future, especially if it's equipped with a satellite-based navigation
system.  My feeling is that the total cost of a carrier battle group
-- the destroyers, the submarines, the copters, everything else -- is
far too high to be worthwhile.  As you point out, almost all of its
resources are devoted to protecting the offensive power of *one* ship.
For the same money and crew, we could probably deliver more military
power with other configurations.  Furthermore, such a battle group
would have far greater survivability -- it wouldn't be helpless if it
lost the carrier.

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Date:  1 Jul 1982 1851-PDT
From: Jim McGrath <CSD.MCGRATH at SU-SCORE>
Subject: Re: US defenses

I don't think Canada will literally go the way of Cuba - but there is
real danger of fragmentation and extremists seizing power in that
nation.  I don't think absorbing Mexico would adversely affect our
security - as long as such absorbtions were gradual, I feel sure that
our good old federal government would "level" the new territory,
making it richer and politically more stable.

A different perspective is perhaps involved here - it might seem
strange to people in the northeast that we could absorb Mexico, but
from the Southwest the situation is different.

Ultimately I think the US should expand simply because we have the
best system of government currently available on any respectable
scale.  I am sure that South Americans would generally appreciate the
wealth and stability they would secure if only they were treated as
equal partners in governing.

Jim

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End of Arms-D Digest
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