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"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 to withstand 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 was very 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 of 45 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.

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.

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 with external "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.

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 life span 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.

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.

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.

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