By David Hughes
Pity the designer of a Second World
War at Sea game as he ponders what
defence value to give to a modern battleship.
The number of variables is immense. The
most obvious is the thickness of both belt
and deck armor, but this is affected by
the area covered and the quality, type
and inclination of steel used. Underwater
protection is equally important, but here
the number of factors involved explodes,
ranging from the width and filling of the
protection system to how far down the main
armor belt extends. Add the issue of turret
armor, consider the beam of a ship (which
influences whether a shell which gets through
the armor will reach a magazine), decide
whether it matters whether or not the captain
is protected, and one is getting close
to determining what the protection value
The new United
States battleships of World War II had excellent deck protection — thick
and placed on an upper deck — probably
better than any European battleship, not
surprising since the United States Navy designed
its ships to fight the Japanese Navy at long,
very long ranges in the clear air of the
Pacific, using spotter aircraft to control
gunfire. Note the weasel word "probably," since
there are so many variables to consider.
Of these the most significant is the quality
of armor, not just its thickness.
Perhaps to many readers' surprise, the United
States was not able to manufacture the best
type of battleship armor, known as "face-hardened" (Class
A in American terminology) in adequate quantities.
That which it could produce was seriously
inferior to, for example British and Italian
armor. I am going to try to avoid a string
of statistics in a Daily Content article
(for those go to innumerable Internet sites)
but will consider one very common comparison
between Iowa and Vanguard (King
George V has a virtually identical armor system, but
is a smaller ship).
Put exceedingly simply, the American belt
is just over 12 inches, the British just
under 15 inches. However, if we take into
account the relative quality of the steel,
the British belt "increases" to
over 17 inches. Incidentally, Italian and
probably French face-hardened steel was also
superior, while the Japanese is marginally
inferior. Also the sad shortage of American
face-hardened steel meant that only the upper
half of the belt could use this type of armor.
Old and new. Wisconsin tied up
alongside the wreck of Oklahoma, 1944.
It is always assumed that the inclined belt
of the American battleships was a distinctive
advantage, and indeed its inclination of
19 degrees equates to a thickness of 17.3
inches of vertical armor at 25,000 yards
range, although this improvement was much
reduced at closer battle-ranges. However,
it is also forgotten when comparing modern
battleships that almost all used inclined
armor. The slab-sided King George V class
appears to be an exception, but it had a
more complex system, vertical where the ship
had its greatest breadth, but inclined (at
up to 14 degrees) beside the turrets. As
with the Bismarck, this meant that the water-line
armor would be at a greater distance from
critical points placed along the centre-line
of the ship.
Unlike the King George V class, the belt
of all three completed American battleship
classes was internal. This is a convenient
way of saving weight, but means that there
is an empty space between the belt and the
hull, which was made of heavy (not armoured)
steel. This created a problem, shown when South Dakota was fighting Kirishima. Cruiser
and even destroyer shells proved quite capable
of piercing the hull so that the battleship
took on over 800 tons of water. She was fortunate
to be saved by Washington allowing her excellent
damage control parties to check most of the
One of the reasons some modern commentators
ignore this problem is their assumption that
the thin outer skin "de-capped" armor-piercing
shells (stripping its very hard outer coat).
This was always a dubious assumption, since
ship designers made no such claim and it
has now been determined that the hull "armor" had
no effect on British, German and Italian
shells or, one suspects, on Japanese ones.
The problem with internal belts was quickly
recognised when ships equipped with them
went into service. Just as the Royal Navy
replaced the internal belt of Nelson with
the external of King George V, the United
States Navy was making the same change just
as the first Iowa class were being built.
The truly magnificent Montana class (by virtually
any calculation the best battleship design
ever authorised) instead used a thick external
The magnificent Montana class.
American designers placed great emphasis,
more than any others, on protecting the main
turrets and the control towers. The former
got some 19 inches of armor, almost 30% more
than their British, German and Italian contemporaries,
although it should be noted that this was
partly because of the lack of face-hardened
steel. Non-hardened (homogeneous) steel needed
to be thicker to achieve the same effect.
Much more controversial is the massive protection
given to the control tower. While the captain’s
station of King George V had to make do with
a mere three inches of armor and an Italian
captain had nine inches of armor, an American
captain was safe behind a towering column
of 17-inch-thick armor plate. Only the mighty Yamato provided its command crew with thicker
protection. In all probability this was wasted
effort and possibly dangerous, as this mass
of steel was located so high up in the ship.
After the war it was recommended (but not
implemented) that the armoured columns be
reduced or removed, as the stations protected
could be easily duplicated in other parts
of the ship.
None of this is intended to suggest that Iowa and her earlier siblings were poor designs
or inferior ships. In several critical respects
they were superior to those of other nations.
However, because they were active long after
other battleships had been scrapped they
assumed almost mythical properties. While
sailing beside Jean Bart or Vanguard an Iowa looked good but not outstanding; when they
were gone they became “the very best,
Consider a contemporary case. Today just
about every American writer or television
program will state, not merely claim, that
the M1 Abrams tank is the "the best
in the world." Very understandable and
patriotic and no doubt exactly the same as
a German would claim of the Leopard II, a
Frenchman of the LeClerc or a Briton about
the Challenger II. Because these complex
and competent tanks exist side by side we
can compare and recognise that all have strengths
and weaknesses, such as the superb protection
but inferior engine of the Abrams.
Surely when we are judging the values we
put on cardboard counters we can recognise
that 60 years ago the same applied to battleships.
That, for example, South Dakota had superb
engines, magnificent damage control but inferior
quality amour. Or that the heavy shells in
her guns were better at penetrating enemy
armor, but because their extra weight was
achieved by reducing the explosive content,
might cause much less damage if they did.
The end. South Dakota and two cruisers
laid up at Philadelphia, 1961.
Remembering that all were truly magnificent,
superbly protected, and seriously deadly
warships, I will in a future Daily Content
suggest some amended values for these ships
in Second World War at Sea.
See for yourself how the
U.S. battleships perform
in Second World
War at Sea: Arctic Convoy!