16″/50 Gun vs. 18.1″/45 Gun

Comparison of armor penetration values Against Side Armor

Notes:

– Blank spaces indicate no data available.

– Figures are for armor-piercing shells. Yamato’s shells weighed 3,219 lbs. fired at 2,599 fps. Iowa’s shells weighed 2,700 lbs. fired at 2,500 fps.

– Figures in parenthesis indicate data from Janusz Skulski’s Anatomy of the Ship: Battleships Yamato and Musashi.

Range (yards)	Iowa 16″/50 Gun	Yamato 18.1″/45 Gun
0	32.62″	34.06″
20,000	20.04″	–
21,872	–	19.48″ (22.28″)
25,000	17.36″	–
30,000	14.97″	–
32,808	–	14.22″ (16.38″)
35,000	12.97″	–

Evaluation

Based on the available and interpolated data, the Yamato’s 18.1″/45 guns firing armor-piercing shells possess slightly greater armor penetration qualities at all ranges when compared to the Iowa’s 16″/50 guns.

As mentioned in previous posts, Garzke and Dulin (1985) opine that the Yamato’s 18.1″ guns were, at best, mediocre for their caliber. However, they also note that this statement is only of general accuracy (p. 89). Furthermore, Grazke and Dulin (1976) note that despite the heavier Japanese shells, the U.S. 16″/50 guns could match their penetration performance due to the U.S. armor-piercing shells possessing greater relative frontal density (p. 203).

Thus, at nearly 74% of the weight of one of Yamato’s 18.1″ guns, a 16″ gun from an Iowa produces nearly the same penetrative results.

Perhaps the real question is:

Does slightly better armor-piercing performance at all ranges equate to any kind of tactical superiority?

Yeah…call me crazy, but I’m going to have to defer to the experts and say that the differences between the two guns with regard to their armor penetration capabilities are marginal at best.

As I mentioned in my book review of Garzke and Dulin’s Battleships Trilogy, expertise on battleships and naval architecture is hard to come by. I find a lot of the evaluations on battleships to be amateurish and akin to hagiography. “Yamato had the largest displacement and biggest guns of any battleship, therefore it’s the best battleship ever!” It’s too simplistic to base our evaluation merely on gun caliber size. If the relationship were always linear then bigger would always equal better. As an exercise in the fantastical, we might as well build a ridiculously massive battleship with modified German Schwerer Gustav 31.5″ guns mounted on it. However, such a ship would be totally impractical and probably prohibitive in terms of resources. Somewhere along the line, we’d reach the point of diminishing returns. But hey, I’m no naval architect.

The truth is likely far more complex. While a battleship is essentially a platform for large-caliber guns, a warship is really a complex configuration of systems. It’s more than just the guns. Less glamorous things like fire control, sensors, hull characteristics, and even the intangibles like crew performance and morale have major effects on combat performance. All of these things are vital and need to work together in close coordination for any ship to fight well.

For a very detailed comparison of different WWII battleships, I’ll refer you to Jonathan Parshall’s excellent article, “The World’s Best Battleship” on Combinedfleet.com

Conclusion

Since an Iowa and Yamato battleship never actually met in a gun duel, we can only speculate as to the potential outcome. If it’s any indicator of their usefulness, it’s worth noting that both the Yamato and Musashi (and the converted Shinano) are at the bottom of the sea. Both were sunk by waves of carrier aircraft (the Shinano by the submarine USS Archerfish). In contrast, all four of the Iowa battleships are preserved as museums. However, the failure of the Imperial Japanese Navy and the success of the U.S. Navy in WWII can very much be found in the sheer economic differences between the two countries.

Battleships used to be seen as the ultimate arbiters of sea power. They were visible indicators of a country’s political, economic, and military might. The more battleships a country had and the bigger they were, the more attention people paid to them. However, WWII spelled the death of battleships and carrier air power became the deciding factor in naval striking power. Today, aircraft carriers are stronger indicators of naval might. If anything, the value of these guns and battleships is debatable given the fact that there are no active battleships in commission anymore. Even the largest naval guns in current use are only in the neighborhood of 5″ with 6″ guns in development. Since the U.S. Navy is focused on projecting power from aircraft carriers, the largest surface combatants are designed to support their mission and are incapable of mounting heavy guns. We could easily spend hours looking at the sheer economics of crewing and operating old WWII battleships in the modern era, but suffice it to say, it would not be cheap.

Missiles, over-the-horizon capabilities, digital technology, and precision striking power have more or less replaced the brute force that battleships bring to the table. An emphasis on multi-mission capable vessels, more efficient use of resources, and smaller shipbuilding programs essentially assures us that the only surviving battleships will likely remain as museums.

References

Garzke, W.H., & Dulin, R.O. (1976). Battleships: United States Battleships in World War II. Annapolis, MD: Naval Institute Press.

Garzke, W.H., & Dulin, R.O. (1985). Battleships: Axis and Neutral Battleships in World War II. Annapolis, MD: Naval Institute Press.

Skulski, J. & Draminski, S. (2017). Anatomy of the Ship: Battleships Yamato and Musashi. New York, NY: Conway.