From: gherbert@crl3.crl.com (George Herbert)
Newsgroups: sci.military.naval
Subject: Re: Were Battleships starting to become obsolete by the time of 
	Dreadnought?
Date: 29 Jan 2000 17:00:08 -0800

Yama  <tjama@paju.oulu.fi> wrote:
>George Herbert wrote:
>> If this is indeed a threat, and to some degree it obviously is, then you
>> just wrap the radars in a couple of inches of kevlar armor (nearly radar
>> transparent, and quite bomblet-proof).  Same with antennas.
>
>I also ask, why this is not done?

Current ships devote small percentages of their mass to
hardening, preferring to spend it on active defenses and
decoys and such.  That does not mean that if you are
designing a ship to go inshore against known artillery
the tradeoffs involved may not be different.

>Second, you might want to consider how much it will weight.

Of course.  Say you have a 1m diameter radar antenna and want to
cover it in a 2.5 meter diameter hemisphere of 2 cm thick radome
made of kevlar/epoxy.  Density is around 1.75, area is around
10 m^2, volume is around 0.2 m^3 and mass around 350 kg.

>Third, even if it would protect against submunitions, would it protect
>against normal HE?
>Would inch or two Kevlar armor stop 152mm or 220mm projectile? I
>doubt.

Direct hit?  No.  Nearby hit and blast/fragmentation damage?  Yes.
You need to avoid cheap kills this way (i.e., prevent fragments,
blast damage, or submunition weapons from killing the radar)
but avoiding any damage ever is obviously impossible, for the
same reason it was impossible to make Battleships completely shellproof.
You have to design to avoid cheap kills and absorb a number of
good hits, but there are always vulnerable areas.

>> >They do not need AP ammo. In fact HE or submunition would be preferable.
>>
>> Only if the vulnerable sensors aren't properly armored.
>
>Even if they were, they could still cause fires.
>
>There is reason why modern warships do not carry armor belt. It is because it's
>pointless.

However, there *is* a reason Kevlar is being fitted in spots to new
design US warships, cable runs are now armored and duplicated on
opposite sides of the ship for some functions, and the like.
It's called survivability.  Warships post-WW-2 went into a design
period where it was thought that since you couldn't armor enough
to resist bombs and missiles, most passive defense design features
were a waste, and design for damage control was the only real issue
(and then only for some navies, relatively...).  Aircraft design
went through the same thing, until post-Vietnam detailed studies
led to the suprising conclusion that very simple minor changes and
hardening a few key parts could easily halve the vulnerability of
an aircraft to typical weapons.  Things like not running redundant
control systems through the same conduit, because if you do then if
a shell or missile fragment hits the one conduit, it destroys both
systems at once.  Beefing up a few key systems and here and there and
a tiny bit of armoring.  Designing with multiple structural members
able to take the loads if one failed or was blown away by a hit.

For a warship, armoring CIC is one such survivability measure,
as is armoring the bridge, cable runs, if you're worried about
them (i.e., going inshore) armoring key sensors somewhat etc.
Avoid the cheap kills; make the enemy work for their damage and
really do it.

>[...]
>Then, why bother with battleships...aircraft are much better.

Aircraft cannot provide 24 hr coverage over a battlefield
unless you have a lot of aircraft.  They are also vulnerable
to countermeasures such as SAM and AAA.  They cannot operate
(in the sense of attack targets on the ground) in all weather
conditions.  The fallacy of using Aircraft only was what nearly
sunk Israel's defense in 1973.  Once / if air defenses get good
enough you're out of luck; if you don't have enough planes,
you're out of luck; if your pilots get too tired out, you're
out of luck.


-george william herbert
gherbert@crl.com