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Re: Stealth and Countermeasures...

From: Alan E and Carmel J Brain <aebrain@d...>
Date: Sat, 04 Dec 1999 13:08:23 +1000
Subject: Re: Stealth and Countermeasures...

Imre A. Szabo wrote:

> I love the way you conveniently describe 16" HE shell and then don't
> mention their effects.  Same goes for the effects of plunging AP and
SAP
> fire against unarmored targets.

Sorry, I thought the article was quite long enough for a GZG-L list as
it was. I'll try to be concise.

a) A 16" HE High Capacity round has possibly 1/5 as much explosive as a
standard 2000 lb bomb (which also has most of its weight in the casing,
rather than the explosive).
b) Despite the above, I really don't want to be anywhere on a ship, any
ship, that's hit by either.
c) Because of fusing problems, SAP rounds are considered optimum vs
ships these days (but see d), as HE rounds often go off too early or not
at all. AP was best against armoured, but isn't carried these days. 
d) But better than SAP vs ships are smart rounds, from WW2-era Proximity
fuses to initiate HE rounds reliably and blow away great chunks of
superstructure, to cluster munitions that elimate sensors and
communications, to pattern-recognising targeters that go for vulenarble
points.

> > With a missile like a Sunburn, or the dreaded AS-6 Kingfish, it's a
> > different matter. There's far less metal, but a whole heap more
> > explosive.
 
> But you don't have the kinetic energy for shore bombardment.	A very
big
> minus point.

A 16" AP shell on a plunging trajectory is an excellent bunker-buster.
Better than any air-delivered bomb (except for special purpose
penetrators).
But it didn't work very well in Vietnam. Example: One bunker, made of
nothing but rammed earth, took multiple 16" hits without destruction.
Then again, it took several 750- 1000- and 2000- bomb hits too. It then
took 3 M-48 tanks driving on top of it. Demolition engineers eventually
cratered it out with several tons of C4 etc.
AS you can gather, the bunker was rather thick. And the original rammed
earth was at least 1000 years old, and had been added to in every war
since then.

Summary: Which is better,
a) 16" SAP with an approx 1-metre concrete penatration at high angle
b) 2000 lb warhead from a guided bomb or missile at low velocity, also
capable of similar penetration (see Desert Storm for proof)
c) 81mm Dumb Mortar round.

Answer: c) if a) and b) aren't available.


> A lot of research has been done on this.  Good designs don't have
vital
> components outside of the protection envelope. 

True. But how vital is vital? Magazines are vital. Steering is vital.
Fire Control is vital. Weaponry is vital. Buoyancy is vital. Propulsion
is vital.
Even the Iowas (probably the best protected ships ever built) don't have
that half-metre thickness of armour everywhere "vital". e.g. the
secondary weapons, the Tomahawk launchers, the radars, the
communications antennae, about 40% of the waterline etc.

Sounds as if you know your onions on this one though. May I recommend
Friedman's "Battleship Design and Development". I met the guy at a Royal
Navy Equipment Exhibition awhile ago, and he's the best source I know on
warship architecture and the compromises that have to be made.

 The "turtle deck" design
> of the Bismarck and Trippitz were quite bad in this respect, and how
> much of a pounding did the Bismarck take with this less then ideal
> design after a lucky torpedo hit???

Main problem was a weak stern, aft of the citadel. Frame A32 IIRC.
German naval architects never did get this right, most of their designs
from destroyers upwards were too weak there.

>  The Iowa's design is very good and
> would take much more damage.	A modern battleship would be even
> better...

Concur.
 
> > an Otomat or other small
> > terminal-diver coming in could cause serious (non-fatal) grief. And
20
> >
> > of them would almost certainly result in the ship's destruction.
> 
> Let's shoot a Nimitz with 20 too while where at it.  A modern BB would
> have a chance survival.  Would the Nimitz???

Better than you think: I forget the name of the US Carrier that had a
Really Bad Day in the gulf of Tonkin in the 60's. An A-6B landed badly,
amidst an alpha strike fully fuelled and armed. Over 20 tonnes of
ordnance went off within a minute, all round the ship's stern.
Equivalent of about 60 Otomats, all in the same area of the ship. Lots
and lots of holes in the 12" of armour that was the flight deck over the
reactor.

Funnily enough though, even a single sea skimmer might have sunk her. A
single warhead entering the side and detonating the contents of the
flight deck might have been more damaging.


> Check the effects of HE shells in Juttland.  One of the German ships
was
> using them exclussive.  While it did degrade enemy fire, it was not
> nearly as effective as they hoped.

..but the Brits were the ones who mainly used Common Shell, and it was
that rather than their p*ss-poor AP that did the damage.

>  These rounds (and missiles) are best
> against lightly or unarmored targets.

Absolutely True, agree completely.

>  Nimitz's, Tico's, etc.

With the caveat that any CVN's flight deck is heavily armoured, agree.

> With
> satellite guided rounds, effects of damage to ship fire control is not
> as disabling as you suppose.

Um. Why not?

>  As for one AS-6 taking out a turret if it
> gets a lucky hit; gee, the battleships got 3 more...

Though only 2 operational, as the relevant magazine would be flooded as
a safety measure. Maybe it's my British Heritage, but such names as
Hood, Queen Mary etc spring to mind.

>  One AS-6 will
> probably operationally kill a Nimitz WITHOUT a lucky hit...

For 6 hours, yes. (Based on Gulf of Tonkin data above)
 
> >  Give it a precursor warhead, and its speed would
> > cause
> > it go through the deck armour too. But better would be to give it an
> > EMP
> > warhead to KO the ship's electrical system.
> 
> Speed alone will not cause it to go through the deck armour.	It will
> have to have an airframe capable of withstanding the shock without
> breaking up.	If you do that, you end up with a SAP Sunburn.

Correct, but precursor warheads are very bulky (won't fit in a gun
barrel OR won't stand the shock) but light. So instead of using 90% of
explosive traded for metal to batter your way through, you only lose
10%.

>  But an EMP
> warhead would be so much more useful against a Nimitz.  90 airplanes
> without functioning avionics.

Very true.

>  The battleship would still require one massive pounding to
> put down.

One under-the-keel explosion under the stern would take out the props.
OK, the ship isn't sunk. Heck, if some people are to be believed, the 5
longtitudinal stringers on the Iowas mean that it would take dozens of
underkeel hits to discomfit them (and Carriers likewise I might add).

But one, just one hit near the props will make that 100,000 t of
fighting ship into 100,000 t of very heavily armed unpropelled barge.
Fitting new props (which weigh hundreds of tonnes each) is a long job
for a shipyard. Assuming the shafts haven't ripped holes in the side -
not an unreasonable assumption in a very well built ship.

Remember Bismark was sunk by her crew opening the scuttles. But this was
hours after she lost all communication, propulsion, and ability to
fight. 

A 100,000 tonne ship in littoral waters that has its propulsion KO'd is
a nightmare. Towing it out of battle would be an interesting exercise.

BTW I'm a mere spectator at the great "BB vs CV" fight. THe CV
proponents  greatly overstate their case, but the BB ones even more so.
There's a very good case for a new Monitor, but I know the technology in
the Iowas, and	putting them back in service would be a Very Bad Idea
Indeed.
    
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