comparing wwii battleship

7/28/2019 Comparing WWII Battleship

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Let's say you want to

"Build a Better Battleship"...

Introduction Battleships reflect the culmination of centuries of development of seagoing fighting vessels.

The three basic capabilities of a battleship are the ability to deliver significant punishment, the ability towithstand similar punishment and the ability to move to a combat area and within a combat area. In short,

these can be summed up as Firepower, Protection and Speed. It is nearly impossible for a vessel to be

designed to excel in all three categories. However, the Iowa Class battleships come closer to achieving this

perfect ideal than any other ship ever built. Because of this, these four ships have been able to provide useful

service to the United States Navy during five decades of service.

Balance It is possible to build ships with big guns, or heavy armor, or great speed. It is also fairly easy to

build ships with two of the three design objectives met. However, achieving a balance of all three design

objectives is very difficult indeed. Doing so under treaty imposed weight restrictions becomes almost

impossible.

Each navy tended to have their own preferences or design philosophy. The Royal Navy of Great Britain wasvery fond of the "battlecruiser" concept. A battlecruiser was a lightly armored fast ship with the armament of

a battleship. On the other hand, Germany's High Seas Fleet of World War I and the Kriegsmarine of World

War II tended to prefer fast ships with heavy armor, but with relatively light armaments. The United States

Navy believed in maximum firepower and protection at the expense of speed, at least until the new "fast

battleships" were completed in the 1940s. Only the Iowa Class ships could be ranked among the best

protected, heaviest hitting and fastest battleships ever built.

In the following sections of this article, each attribute of battleship design will be covered in more detail, and

some prominent ships will be compared. Note that these comparisons use total scores to rank the ships.

Arguments can be made for using any of a number of comparison methods, and entire volumes have been

written on the subject. However, observation of the details in the design of these ships can prove fascinating,regardless of the ranking method.

Firepower

The firepower of a ship is most often equated to the projectile diameter of the main battery. Therefore a ship

with fourteen inch guns would generally be considered to be inferior to a ship with fifteen inch guns, and so

forth. However, firepower can be further broken down into several important categories.

First of all, the diameter of the gun is only part of the story. Several variants of each diameter gun were

usually developed over time by each navy. Generally, later guns had longer barrels and therefore higher

muzzle velocities of the projectiles. The ratio of the projectile diameter to barrel length in naval guns is

referred to as gun caliber. For example, a sixteen inch 45 caliber gun (16"/45 for short) had a barrel length of45 times sixteen inches, or 60 feet. A 16"/50 gun had a barrel length of nearly 67 feet. The table below shows

the improvements to be gained by increasing gun caliber.


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Gun Comparison

16"/45 16"/50

Shell Weight 2,700 lb. 2,700 lb.

Muzzle Velocity 2,300 fps 2,500 fps

Maximum Armor Penetration:

at 30,000 yards 12.77" 14.97"

at 20,000 yards 17.62" 20.04"

at 10,000 yards 23.51" 26.16"

Point Blank 29.74" 32.62"

Obviously, gaining better than two inches of armor penetration can make a big difference in a ship to ship

duel.

The second factor that affects overall firepower is the rate of fire. Smaller guns are easier to load, and

therefore can fire more rapidly. Other factors affect rate of fire, such as the design of the shell handling rigs

and loading mechanisms. And the skill level of the crew contributes greatly to the rate of fire of any gun as

well.

A common way to increase the rate of fire of a battleship is to increase the number of barrels in the main

battery. To a lesser degree, the arrangement of those barrels in turrets also plays a factor. Obviously, having

twelve guns is better than eight since more shells result in greater hit probability.

A final firepower factor relates to the accuracy of the fire control systems, as well as the training level of the

crew aiming the guns and spotting the splashes. In short, the firepower of any battleship must consider the

following factors:

o Penetration Capability (size and muzzle velocity)

o Rate of Fire (Reload Time and Number of Guns)

o Accuracy of Fire

Increasing the size and number of guns is very weight intensive. Training can provide an alternative to this -

the Germans, for example, concentrated on using rapid fire with great accuracy using relatively small guns to

balance the larger guns of enemy vessels likely to be encountered. The following table lists some notable

ships from the First and Second World Wars (contemporaries of the Iowa Class) and their armaments.

Firepower Table

Year Navy Ship PCT Total Gun Size Cal. Qty. Rate

1939 Germany Bismarck 118% 16,920 15 inch 47 8 3

1942 USA Iowa 100% 14,400 16 inch 50 9 2

1936 Germany Scharnhorst 95% 13,612 11 inch 55 9 2.5

1923 Britain Nelson 90% 12,960 16 inch 45 9 2

1941 USA South Dakota 90% 12,960 16 inch 45 9 2

1919 USA Tennessee 88% 12,600 14 inch 50 12 1.5

1939 Britain KGV 88% 12,600 14 inch 45 10 2

1940 Japan Yamato 86% 12,393 18 inch 45 9 1.75

1913 Japan Fuso 79% 11,340 14 inch 45 12 1.5

1913 Britain Queen Elizabeth 75% 10,080 15 inch 45 8 2


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1915 Germany Bayern 75% 10,080 15 inch 45 8 2

1919 Britain Hood 75% 10,080 15 inch 45 8 2

1935 France Richelieu 75% 10,080 15 inch 45 8 2

1935 Italy Vittorio Veneto 61% 8,775 15 inch 50 9 1.3

1919 Japan Nagato 52% 7,488 16 inch 45 8 1.25

In the above table, total gun quality is derived by multiplying the gun size and caliber by the number of guns

in the battery and the rate of fire. Note the great improvements in firepower of the "New Battleships." The

PCT column indicates the firepower of each ship versus the Iowa class battleships as a standard of measure.

Only the Bismarck with her superior rate of fire scores better than the Iowas. The Yamato, although armed

with eighteen inch guns, had a relatively slow rate of fire, and in reality her 18"/45 guns were nearly

identical in performance to the superb American 16"/50 gun.

Protection

In general terms, "Protection" relates to a battleship's staying power. The general design objective is to

provide protection against shells the size of the ship's main battery. For example, if a battleship is firing 16"shells, it should be able to withstand incoming 16" shells. As in firepower, many factors contribute to a

battleship's general defensive capabilities.

First, and most obvious, is armor protection. Armor is hardened steel designed to provide protection from

incoming projectiles. A revolutionary concept in battleship design called for "all or nothing armor." The

concept was to place the maximum armored protection over the vital areas of the ship and leave the rest of

the ship virtually unprotected. By doing so, the weight can be spent in armor where it would do the most

good. The general thinking of "all or nothing armor" was that if the ship was hit in a critical area, that area

would be well protected so it wouldn't matter. And if the ship was hit in any other area, that wouldn't matter

either. Using the "all or nothing" principle, the most protection was usually provided over the magazines and

gun turrets. This resulted in an armored box, sometimes referred to as a "citadel" or "raft body" that enclosed

the vitals of the ship. One other trick that was employed in the newer battleships was the implementation of

angled armor plates. By angling the armor, the effective thickness was increased from standard vertical

armor. And while the older ships simply had flat armor plates attached to the exterior, newer ships had

tapered and angled armor belts incorporated into the ship internally.

Another great concern to battleships was protection from torpedoes and mines. Modern ships had multiple

layers of compartments in the hull that were designed to reduce the effectiveness of waterline explosions.

These layers could be "wet" or "dry." Wet layers were kept loaded with fresh water, fuel or even sea water,

so that if these compartments were punctured, their contents would be contaminated but they would not

"flood" since they were designed to be filled anyway. Dry layers were designed to be kept empty so that the

explosion of a mine or torpedo would have an area for the force of the explosion to be dissipated without

violating the structural integrity of the inner layers of the ship. Many of the old battleships were fitted withexternal "torpedo blisters" that were added to the hulls of these ships to provide extra layers of protection.

Another critical factor in battleship design was the implementation of damage control procedures and

systems. Since the "all or nothing" concept and "torpedo blisters" were designed to give way and flood, these

ships had to allow for counter-flooding to keep them level and on an even keel. Also newer battleships were

fitted with extensive pumping and fire fighting systems, and the crew was specifically trained in damage

control procedures. It was very hard to damage a battleship to the degree that it was unable to float. A more

common occurrence was for the ship to be flooded faster than the damage control parties could deal with the

incoming seawater which would result in the ship capsizing.

Armor Protection Table

Year Navy Ship PCT Total Turret Barb Deck Belt Conn Tons

1940 Japan Yamato 127% 93 26 22 9 16 20 23,852


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1942 USA Iowa 100% 73 20 17 6 12 18 18,700

1941 USA South Dakota 95% 69 18 17 6 12 16 14,200

1935 France Richelieu 92% 67 15 17 7 15 13 16,400

1919 USA Tennessee 90% 66 18 14 4 14 16 8,000

1923 Britain Nelson 88% 64 16 15 6 14 13 11,900

1915 Germany Bayern 84% 61 14 14 5 14 14 11,428

1936 Germany Scharnhorst 82% 60 14 14 4 14 14 14,006

1939 Germany Bismarck 81% 59 14 13 5 13 14 17,256

1935 Italy Vittorio Veneto 79% 58 15 13 6 14 10 13,331

1919 Japan Nagato 77% 56 14 12 3 12 15 13,678

1939 Britain KGV 77% 56 16 16 6 15 3 12,000

1913 Britain Queen Elizabeth 70% 51 13 10 4 13 11 8,250

1913 Japan Fuso 66% 48 12 8 2 12 14 8,588

1919 Britain Hood 63% 63 15 12 3 6 10 13,550

In the above table, total armor is derived by adding the turret, barbette, deck, belt and conning tower

maximum thicknesses. The PCT column indicates the armor rating of each ship vs. the Iowa class battleships

as a standard of measure. Only the Yamato had heavier armor, as she was designed to withstand hits

equivalent to her main battery of 18 inch projectiles. Note also that the total weight of armor varies greatly

from ship to ship. This is due to the fact that the size of the areas to be protected varied greatly according to

vessel size and design philosophy of the particular navy at that time.

Speed

Speed is a very significant factor in battleship design, both on a strategic as well as a tactical scale.Strategically, ships require high speed to get to the theater of operations quickly, or to be rapidly deployed to

engage a foe. Tactically, speed allows a ship to position itself in a battle to its own advantage, and allows a

ship to choose to engage or disengage with an enemy force. A general rule of thumb in ship design is that a

ship should be faster than anything more powerful, and more powerful than anything faster. This allows a

ship to run away if it is mismatched in a fight.

As stated previously, speed was not an important consideration in the design of the first United States

Battleships. While most foreign battleships could steam at 24 knots or so, the United States battle line was

hard pressed to break 20 knots. With the advent of the North Carolina class of United States battleships,

speed was increased to 28 knots. The Iowa class battleships were designed to travel at 33 knots, which would

allow them to keep up with the fast carrier task forces. These ships became the fastest battleships in the

world (quite a departure for the United States Navy). And it was this speed that provided the long useful lifespan of these ships. For at the end of World War II, all of the old battleships as well as the six slower North

Carolina and South Dakota class ships were removed from active battleship duty, never to return.

The following table shows the relative speeds that could be attained by each of the ships in our study.

Speed Table

Year Navy Ship PCT Speed Horsepower Displacement

1942 USA Iowa 100% 33 212,000 52,000

1936 Germany Scharnhorst 97% 32 165,000 34,841

1919 Britain Hood 94% 31 144,000 36,300

1935 France Richelieu 94% 31 150,000 43,000


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1935 Italy Vittorio Veneto 91% 30 130,000 44,000

1936 Germany Bismarck 88% 29 138,000 36,300

1939 Britain KGV 85% 28 110,000 40,000

1941 USA South Dakota 85% 28 130,000 42,000

1919 Japan Nagato 82% 27 80,000 33,800

1940 Japan Yamato 82% 27 150,000 69,100

1913 Britain Queen Elizabeth 73% 24 75,000 27,500

1913 Japan Fuso 70% 23 40,000 30,600

1923 Britain Nelson 70% 23 45,000 35,500

1915 Germany Bayern 67% 22 48,000 28,006

1919 USA Tennessee 64% 21 30,000 32,300

As the chart above shows, the Iowa class battleships were the fastest capital ships ever built. Note the

increase in horsepower required to drive ships at high speeds.

Weight & Size Weight and size were very important considerations in battleship design. Weight was a

consideration to be met for treaty compliance, and size was important because the ships had to fit through

canals and into dockyards and such.

Both weight and size led battleship architects in a vicious circle. A heavier ship needed more horsepower to

keep up to the designed speed requirements. The machinery to drive ships at high speed took up large

amounts of space. In order to protect these large spaces, extra armor needed to be allocated. The extra armor

covering larger spaces adds weight. Thus you need still higher engine horsepower requiring even more

space, and the cycle continues. Add increased firepower into the mix and you have a real mess.

The Iowa class battleships are a unique achievement in battleship design. Not only are they fast, but they are

heavily armed and well protected. Furthermore, they were designed with a standard displacement to comply

with the 45,000 ton limit imposed by treaty. And, to add further impossibilities to the mix, they were narrow

enough to pass through the Panama canal - the other two "winners" in our comparison, the Bismarck and

Yamato classes were too wide to fit in the locks of the canal.

Overall Comparison The chart below presents the ships featured in this article ranked by total percentages.

Since the Iowa class is used as the standard for this article, it scores 300%; a full 100% in each of three

categories. The other ships are measured against this standard with the total score appearing to the right of

this chart.


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The Iowa class battleships remain unmatched to this day. Although there are no longer any enemy battleships

to fight, they are unmatched in their ability to blast shore based targets. Their armor makes them nearly

invulnerable to anti-ship missiles in use today. Their speed allows them to keep up with the fastest elements

of the United States fleet. And with upgraded weapons systems including anti-ship missiles and cruise

missiles, the Iowa class battleships remained versatile and useful tools for our nation's defense. Isn't it

interesting that the one consideration taken for granted during their design -- the cost of sending them to sea

and assembling a crew -- is the one factor that led to their demise.

comparing wwii battleship

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