The Des Moines class cruiser was designed during the peak of
WWII and incorporated all the lessons learned about naval combat to that
point. More importantly, it was designed
by people who were actually fighting a naval war as opposed to the people
designing ships today who have no first hand knowledge of combat and,
seemingly, no awareness of history or history’s lessons about warship design. The class can, in many ways, be considered
the ultimate development of the cruiser.
As such, it would behoove us to examine the design and see what
characteristics its designers focused on and why. Presumably, we should be valuing the same characteristics
in our designs today or, if not, we should have a very carefully thought out
rationale as to why not along with supporting evidence and data to demonstrate
why we believe that the lessons of actual naval combat no longer apply.
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| Des Moines Class Cruiser |
While the design work began around July 1943 with final
design characteristics approved in November 1943, the lead ship, Des Moines,
was laid down in May 1945 and commissioned in November 1948, too late for the
war.
As a brief summary, here are some specifications of the Des
Moines class.
Des Moines Class Specifications (1)
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Length (overall), ft
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716
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Displacement (full load), tons
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20,950
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Beam (waterline), ft
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76
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SHP, hp
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120,000
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Speed (trial), kts
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32.5
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Range @ 15 kts, nm
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10,500
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Main Battery
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9x 8”/55 (3x triple
mounts)
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Secondary Battery
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12x 5”/38 (6x dual
mounts)
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AA Battery
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24x 3”/50, 12x 20mm
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Fire Control
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2x Mk54 (8”), 4x Mk37
(5”), 4x Mk56
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Armor Belt, in
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6-4
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Bomb Deck, in
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1
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Armor Deck, in
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3.5
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Bulkheads, in
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5
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Barbettes, in
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6.3
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Main Mount Armor, in
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up to 8
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Conning Tower, in
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up to 6.5
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Let’s take a brief look at the design characteristics that
are evident from the specifications.
Armor – With a 1”
bomb deck (intended to detonate armor piercing shells and high explosive bombs
before they reached the main armor deck), 3.5” armor deck, up to 6” main belt,
and heavily armored main gun mounts, the class was well equipped to stand and
fight and continue fighting while absorbing damage. We’ve completely forgotten just how well
armored ships used to be. Imagine a Des
Moines class cruiser going up against the 57-76 mm guns so prevalent in today’s
navies. The cruiser would be almost
invulnerable to gunfire. Even 5” gunfire
effects would be greatly mitigated. Of
course, anti-ship cruise missiles are a different story, to some degree, and no
one is suggesting an exact duplicate of WWII armoring schemes for modern ships
(see, “Conceptual Armor For Modern Ships”).
However, the lesson that armor mitigates damage and allows ships to stay
in the fight is a timeless reminder of the reality of combat and one that we
have forgotten, today. WWII warship
designers understood this even though we’ve forgotten the lesson, today.
Speed/Range –
Capable of 32+ knots and a range of 10,500 nm at 15 kts, the Des Moines was
heavily armored for her size and reminds us that we don’t have to sacrifice
speed or range to achieve armor.
Contrast this with the entirely unarmored LCS which is only capable of
around 37 knots (see, “LCS – Not All That Fast”) – hardly much more than the
Des Moines while being significantly lighter!
So many people have commented that armor means less speed and
range. They’re wrong and the Des Moines
specifications prove it conclusively!
Modern ship designers have completely forgotten how to achieve the
combination of speed, range, and armor that we routinely met in WWII ship designs.
Battery – The Des
Moines carried a heavy and numerous main and secondary battery. We’ve forgotten just how densely packed WWII
ships were with weapons. Weapon density
(redundancy) is what allows a ship to keep fighting even if one or more weapons
are disabled. It is also worth noting
the secondary battery which was numerous and powerful. Compare that to today’s ‘secondary’ batteries
– for those ships that even have one it generally consists of one or two 30 mm
guns or some such. This reminds us that
there is value in a powerful secondary battery in the event that the main
battery is disabled. It also provides an
alternative for situations in which firepower is still needed but the main
battery would be a vast overkill. The
failure to recognize the value of a powerful secondary battery, today, is yet
further proof that we no longer design WARships.
Fire Control
Redundancy – One can’t help but be struck by the number and types of fire
control systems in the Des Moines class.
In addition, and notably, the Des Moines had two separate main battery
plotting rooms which would provide invaluable redundancy in combat. Contrast that with today’s obsession with
consolidating every sensor into one system which, of course, creates a single
point of failure in combat. As battle
damage accumulates, the more fire control systems that are available, the
longer a ship can stay in the fight.
All of the above characteristics are noteworthy, without a
doubt, however, they don’t add up to a truly special warship. So, is there something else that makes the
Des Moines class special? There is! It’s the rapid fire 8” guns.
8”/55 RF Mk16 – This
gun represented a major step forward with the capability to achieve firing
rates three times faster than previous guns!
As reported by Navweaps website, the 8”/55 routinely demonstrated
sustained firing rates of 10 rds/min thanks to automated shell handling and
loading. As Navweaps states,
…
a fire rate three times greater than that of previous 8"
(20.3 cm) guns and coupled
together with the use of "super-heavy" AP projectiles, these weapons
made the Des Moines (CA-134) class the most powerful heavy cruisers ever built.
(2)
The guns were able to be loaded at any angle – again, a
major benefit – and were able to achieve firing ranges of 30,000 yds (17
miles). Interestingly, the guns used two
radars on each turret for rangefinding instead of optical rangefinders.(2)
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| 8"/55 Gun Turret Drawing |
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| 8"/55 Gun |
We see, then, that the key to the Des Moines class was the
very heavy weapons fit and the ability to fire those weapons three times faster
than any previous 8” gun! Combine this
with a heavy armor fit and the Des Moines was a powerful, effective warship,
for sure. It is little wonder, then,
that the Des Moines keeps cropping up in discussions about modern cruisers and
why modern ships compare so poorly to the WWII class.
The lessons of the Des Moines and the characteristics that
were valued by WWII warship designers were speed, range, firepower, redundancy,
armor, and rate of fire – all of which, except perhaps speed, have been abandoned
by today’s ship designers. What makes us
think that those characteristics of a good warship design no longer apply to
naval combat? What evidence do we have
that those characteristics no longer confer any benefit in naval combat? The answer is … nothing. Only our own stupidity, ignorance, and
arrogance are telling us to abandon the hard learned lessons of actual
combat. We’re substituting our
ignorance-based thinking for combat-reality and the folly of that will quickly
become apparent in the next naval battle.
Indeed, the folly has already become apparent with examples
such as the Norwegian frigate that sank from a simple, limited collision, the
gentle grounding of the Port Royal that mission killed the ship’s VLS and
Aegis, the exterior bomb blast that almost sank the Cole, the two Burke
collisions that almost sank those ships, the French ship that was unable to
launch its cruise missiles, the LCS that cannot repair even the simplest damage
at sea, and so on. Today’s examples are
telling us, loudly and clearly, that our ship designs are garbage and unsuited
for combat. We need to return to the Des
Moines, conceptually, if not literally.
Imagine a Des Moines class cruiser with VLS and some modern
sensors added. It would instantly be the
most powerful surface ship in the world.
(1)“U.S. Cruisers, An Illustrated Design History”, Norman
Friedman, Naval Institute Press, 1984, ISBN 0-87021-718-6, p.481
(2)Navweaps website, retrieved 17-Jun-2020,
http://navweaps.com/Weapons/WNUS_8-55_mk16.php