US Battleship Michigan circa 1910
British Pre-Dreadnought at Gun Practice - Public Domain)

The Evolution of Naval Gunnery (1900 to 1945) Part 1

by Paul F. Watson
January 2014 Updated April 2020
INTRODUCTION:

The great gunnery revolution occurred between 1890 and 1945. During this period, paradigm shifts created the need for new inventions. The result was continual improvement in gunnery. A major thesis of this paper is that evolution of thought resulted in changes of technology and great increase in effective battle ranges.

The stunning improvement in gunnery over time can be seen in Table 1 below, by observing the increase in battle range with generally constant hit percentage.

Date SHOOTER CONFLICT RANGE % HITS SOURCE
1898 U.S.A. Spanish/American 2000 yds 2% (3)(4) Ropp p299
1904 Aug 10 Japan 12" guns Russia-Japan 8700 yds 9% (15) Paul Watson
1904 Aug 10 Russian 12" guns Russia-Japan 9100 yds 4.5% (15) Paul Watson
1905 Tsushima Japan 12" Russia-Japan 6500 yds 19.6% (3) J. N. Westwood
1905 Tsushima Russian 12" Russia-Japan 6500 yds 4.7% (15) Paul Watson
1914 U.K. WWI-Jutland 16000 yds 3% Campbell
1914 Germany WWI Jutland 16000 yds 3.5% Campbell
1939 Hood Bismarck 20000 yds 3.5% Garzke
1939 Bismark Hood 20000 yds 5% Garzke
1943 U.S.A. Guadalcanal 16000 yds yds 16% (2) TBD3
Note: Japanese 9% hits at 8700 yards is roughly equivalent to 19.6% at 6500 yards.
Table 1: Historical Progression of Battle Ranges & Hit Percentages

When nations of similar technical ability compete, similar technologies and capabilities result. This is true for naval gunnery, but development in some countries proceeded at a faster rate. The French invented the high velocity gun, but the British and Germans soon produced similar weapons. The British pioneered central fire control in 1910, but by 1914 the Germans possessed less sophisticated system but with similar capability. In the story of gunnery evolution, the original creator of an idea is often unclear. Military secrecy and loss of records over the years clouds the detail. As a result, the account that follows necessarily relies on most available data which is often British. Despite such reliance, ample evidence exists of roughly parallel developments in France, Germany, America and many other countries.

GUNNERY CONCEPTS:

Early Gunnery Revolution and Results:

From the 1880s, the barrier to development of long range naval gunnery was the wooden ship era mindset. Traditionally, ships rolled with the waves as gunners tried to fire when "iron sites" aligned with their "oscillating targets". Social factors discouraged the experimentation needed for gunnery improvement. The common "spit and polish" attitude discouraged firing of guns as it was always a "dirty affair" (11).

Despite regressive attitudes, some fought hard for improvement. By the mid 1890's the French recognised the value of "observing fall of shot" rather than "site alignment". A few years later, Captain Percy Scott RN discovered the principal of "continuous aim" and modified gun mounts to keep guns on target despite rolling of the ship(12). He combined this with training aids (of his invention) such as the "dotter". By 1900, the British Navy was aggressively improving its gunnery(11).

In 1900, Lieutenant Sims was a young U.S. Navy firebrand. On assignment in Asia, he met and befriended Captain Percy Scott from whom he learned many advanced gunnery concepts. Despite great resistance, Sims doggedly drove the U.S. Navy gunnery revolution, beginning with ideas learned from Scott (12)(14).

Results were stunning both during practice and war. During the 1898 Spanish American War, the U.S. Navy achieved an acceptable 2% hits at about 2000 yards range. Six years later (On August 10 1904) Russian and Japanese battleships duelled in the Yellow sea with the Japanese achieving TBD% (estimated at 6% to 12% by Japanese & 3.5% by Russians - research ongoing (13) hits at ranges varying of 4000 to 12000 yards. Only 8 months later, the Japanese trained in salvo firing (in lieu of traditional turret by turret fire). The effect was devastating and achieved a stunning 20% hits by 12 inch main battleship armament at ~6500 yards range (10).

Nature of The Gunnery Problem:

Naval gunnery is unlike shooting a bb gun at an arcade, where hit after hit can be achieved by a skilled shooter. Naval gunnery is more comparable to a boy standing by a lake who throws rocks at a distant turtle. The splash of the first rock is short and the boy throws harder. Soon, the boy "finds the range"; but even then, he cannot repeatedly hit the target. The arc of the throw and variations of wind frustrate absolute accuracy. The best he can achieve is to drop rocks in a cluster, about the turtle. After "the range is found", some statistical percentage will hit. Naval gunnery is much the same.

For boy and naval gunnery alike, two parameters describe capability.

  1. The time required to "find the range" (i.e. throws before "clustering" about target)
  2. The percentage of hits achieved after "the range is found."
There is a loose connection between these two parameters. Generally, the gunnery system which can find the range quickly, is more likely to keep the range and achieve many hits; however, other factors come into play. Repeated hitting of the target after the range has been found also relies on the "tightness" of the shell clusters (i.e. they should land in a small ellipse) . Ironically, a very tight cluster actually makes finding the range a bit more difficult. (1)

Birth of the High Velocity Gun:

American civil war photos show thick, stubby gun barrels of the period. Photos of contemporary European artillery look much the same. Fast burning gun powder generated tremendous and instantaneous pressure within the gun. Such great pressures necessitated thick, stubby gun tubes.

During the 1870's, French Military Engineers changed all that. They invented slow burning powder which gradually expanded as projectiles accelerated down long and slender gun barrels. The marriage of slow burning powder and long gun barrels resulted in greatly increased shell velocities (2500 ft/sec).

Invention of slow burning powder stopped the progression or larger and larger guns. The twin French inventions (slow powder and long barrels) enabled development of small, quick firing guns capable of "poking holes" through thick armour. The French (and other nations) married this technology with the breach loading (not down the barrel) gun to achieve high rates of effective fire.

Major naval powers were quick to follow the French (7). Britain developed the "wire wound gun" while Germany used shrink fit tube design. Other nations (including the U.S.) purchased gun technology from France, Britain or Germany.

Quick Firing Guns vs. Big Guns:

By 1890, technically advanced navies (France, US, Germany, UK, Russia, Austria & Japan) employed high velocity, breach loading guns. Naval experts around the world understood that big guns were very heavy. The choice was to employ a few big guns, or many smaller ones. From 1890 until 1906, gunnery experts debated the relative effectiveness of a few big, powerful guns (e.g. 12 inch diameter bore) vs. many smaller quick firing guns (e.g. 6 inch to 8 inch diameter bore). Proponents of the quick firing guns argued that the smaller gun would smother the target before the larger gun made a single hit.

The inability to quantify the benefits of small, medium or large guns resulted in battleships of mixed battery. These ships often carried a mix of 12 inch, 8 inch and 6 inch guns to engage other battleships. In addition, they typically carried a battery of 3 inch guns for use against torpedo boats. These "mixed battery" battleships made their debut in the Spanish American War and again in the 1904 Russo Japanese War.

One of the problems of "mixed battery" battleships, was that 12 inch, 8 inch and 6 inch guns would be firing simultaneously at the same target. During the 1904 Russo-Japanese War sea battles, gunners had to fire, wait 6 seconds and then try to figure out which splash was theirs amid the many being made by different sizes of guns. The mixed battery ship made observation of shot fall almost impossible. In early 1905, the Japanese went to "salvo firing" which meant all the big guns fired at once. This improved things, but did not totally overcome problem created by the "mixed battery" armament.

Twin Problems:

The twin gunnery problems are 1) time to find the range and 2) percent hits afterwards. During the 1905 Battle of Tsushima, the victorious Japanese fleet required 15 minutes to "find the range". We might wonder why it took so long.

Returning to the "turtle analogy", a single boy throwing rocks at a turtle quickly finds the range. But when five boys all throw rocks at the same turtle, the problem becomes far more difficult. Each boy becomes confused regarding which splash was his. Often as not, he observes the fall of someone else's rock, and wrongly adjusts his next throw.

At the Battle of Tsushima, likely 20 big guns all fired at the same target. The splashes of 6 to 12 inch projectiles were confused, rendering accurate observation and correction by each gunner impossible. In 1906, British Navy took a bold step to address this problem. HMS Dreadnought was launched. Unlike its predecessors, Dreadnought was armed with 10, 12 inch guns, mounted in twin turrets. There simply were no 8 inch or 6 inch guns to cause confusion. Soon after, all major powers began building "all big gun" ships of their own. The Dreadnought age was born; but, another 6 years elapsed before the invention of central fire control delivered the full benefits of the "all big gun ship".

Invention of Central Fire Control:

The "all big gun" ship greatly reduced the confusion that resulted from splashes of multiple calibers of gun firing concurrently. (Confusion was still possible between the splashes of different 12 inch guns). In 1910, the British Navy carried out secret trials between two identical ships, one using traditional single turret firing and the other equipped with the newly invented central fire control system. The centrally controlled firing system, aimed, elevated and fired all big guns simultaneously. The 8 to 10 projectiles landed simultaneously in a pattern before, behind or around the target. The multiple splashes were easy to observe and all guns were corrected simultaneously. Central fire control ensured that gunnery corrections were correlated to correct observation of fall of shot thus minimising time to "find the range".

Shortly after its introduction, a gunnery competition was held between two identical battleships (Thunderer & Conqueror). One was equipped with the new, central fire control system and the other used the traditional turret by turret command of fire.

Naval officers carefully observed the fall of shot to determine which method was more effective (in terms of finding the range quickly). Detailed analysis confirmed the obvious, that the central fire control system was far more effective than turret by turret fire control. (see Peter Padfield Guns at Sea for details).

The Central Fire Control System offered several advantages over the traditional system. First, all the guns on the ship were fired together thus resulting in a statistical pattern of splashes fitting one of three descriptions:

  1. All short of the target
  2. All over the target
  3. Or a pattern about the target.
The entire splash pattern was easily observed and represented a single ship. There was no possibility of confusion over which splash was from which gun. Unlike single event observation, it was also very clear whether the pattern was centered on the target.

Invention of Fire Control Computers:

By World War I, battle ranges were such that shell flight time was approximately 30 seconds. During 30 seconds, a battleship cruising at 21 kts moved forward 300 yards. A perfectly aimed shell fired at the ship would thus fall harmlessly behind by the time it arrived. Simple math thus dictated that gunnery systems be developed that would enable shooting at the target's future location.

Just prior to WWI, major powers developed mechanical Fire Control Computers which integrated with Central Fire Control Systems to properly adjust the aiming point. The following elements were integrated into an effective system.

  1. Central Fire Control (that controlled all the big guns for both elevation & train)
  2. Quality optical range finders to determine initial enemy range
  3. High up observers in the ship to watch/report the fall of shells to the gunnery officer
  4. Observers to watch changes of course and speed of enemy targets
  5. A mechanical fire control computer which accepted inputs 2, 3 & 4 and predicted where the guns should be pointed to land shells into the future position of the enemy, given the flight time of the shells.

By WWI, Britain, Germany, the U.S. (and likely all other major powers) employed central fire control systems augmented by fire control computers. As a result, WWI naval battles were fought at ranges of 10,000 to 20,000 yards. At those ranges, 3% to 4% hits were achieved despite bad North Sea visibility with 11 inch to 15 inch guns.

While such percentages might appear low, the effect of such gunnery was devastating. During the Battle of Jutland, several British Battle Cruisers were blown apart when German shells pierced British magazines. German ships also suffered with Battlecruiser Lutzow sunk after 24 large caliber hits. Other German had barely a gun turret functional by the end of the battle (e.g. Von der Tann).

Between the Wars:

During the period between WWI and WWII, navies continued to develop more effective technologies. Reports of U.S. Naval practice during 1930s suggests percentage hits expected during battle should greatly exceed the 3% to 4% achieved in the North Sea during WWI. (see Warship International, W. J. Jurens, the Evolution of Battleship Gunnery in the U.S. Navy, 1920-1945). During the 1930-31 practice, three battleships fired 56 shots each (7 salvos) at 12800 yards range. The target was Battleship representative in terms of length and height. "West Virginia would have gotten five hits, Maryland six, and Colorado only one." Assuming such performance typical, 7% hits was achieved during the opening salvos of a mach battle. Records from both the British 5th Battle Squadron at Jutland and American interwar practice suggests about 4 salvos are required to "get the range" and "bracket" an enemy target. From this, we conclude that 3 or 4 salvos were simply thrown away and the long term interwar war hit percentage for American Battleships should be about 14%.

Rates of Fire:

The rate of firing for Battleship main armament increased from 1900 reaching its maximum about1930. For the Russo-Japanese war period (1904-05), Janes Book of Fighting Ships reports normal rate of fire for Russian battleships as one every 3 minutes. It appears the Japanese long term firing rate was similar in 1905. Jurens provides information for a later period. "In 1919, battleship main batteries averaged about 1.9 shots per gun per minutes. By 1930 the rate had risen to about 2.5 (but never got much higher than this).

Radar Fire Control:

During WWII, both the German Bismarck and U.S. battleships were equipped with Radar Fire Control. For the U.S., its effectiveness was such that even during daytime, it was used in preference to optical fire control. During the night actions at Guadalcanal, an American Battleship using Radar achieved 9 hits on a Japanese target after 56 rounds fired. Once again, the long term hit percentage would have been much higher if firing had been prolonged or if "ranging shots" are discounted.


CONCLUSIONS:

From 1890 through 1945 a continuous stream of technological improvements increased battleship big gun effectiveness in terms of:

  1. Battle ranges
  2. Hit percentages
  3. Firing rates

Improvement in gunnery did not result from wishful thinking. Particular concepts and equipment innovations allowed for gunnery improvements. Critical Milestones driving gunnery improvement and range increase include:

Prior to 1906, high rates of fire for the medium gun (6 inch to 8 inch) enabled them to compete with big naval guns (11 inch to 12 inch in that period). From 1906 to 1914, the emergence of Central Fire Control and Fire Control Computers ushered in the period of the Big Gun, a period when destructive power and accuracy of the big gun totally dominated naval warfare.

Battle ranges increased as percentage hits grew throughout the period. In 1898, 2% hits was achieved by the Americans in the Spanish American War at ranges of approximately 2000 yards. By 1905, the Japanese achieved 20% hits at battle ranges of 6500 yards in the Russo-Japanese War. By World War I, 3% to 4% was achievable under the worst sea conditions at 14000 yards range. During the interwar years, 15% hits at 15000 yards was a realistic battle expectation using optical fire control.

While such hit percentages may seem low, the enormous destructive power of each hit deemed it sufficient. In 1904, Russian battleship Oslyabia was destroyed after only a few number of hits. In WWI, German Battlecruiser Lutzow was sunk by 24 hits. Kirishima was effectively destroyed by 9 hits. Battlecruiser Hood was blown up after a very few hits (15). Such observations explain why the Battleship reined supreme for 50 years.

This article presented the thesis that evolution of "concepts" drove invention of equipment resulting in increased percentage of hits and greater battle ranges. Both the pattern of improvement and the stream of technological improvements have been presented in detail. I must conclude that the original thesis has been demonstrated, i.e. "imagination" and "determination" were the primary drivers of naval gunnery improvement.

Notes:
  1. The particulars of various navies differed a bit with respect to tightness of shell grouping. Some WWII accounts reported that the Japanese navy shot very tight clusters, and the Italians loose clusters. The triple turrets (e.g. as used by the U.S. Navy) tended to shoot wide clusters when all three guns were fired simultaneously due to the bow wave effect of the middle shell pushing the other two away. British wire wound guns were known to be excessively limber - tending toward wide dispersion although other practices may have compensated.
  2. During the Guadalcanal night engagement of Washington & Kirishima, the U.S. battleship was using radar controlled firing control.
  3. There is some question whether any 12 inch shells struck Spanish ships during the Spanish American War in 1898. By contrast, Russian battleships during the battle of Tsushima 1905 were struck by many 12 inch shells, vindicating the large caliber weapon as an effective military technology. The 20% hit figure given is a combination of 6 inch, 8 inch and 12 inch hits vs. total number of rounds fired.
  4. Friedman U.S. Battleships p41: "Ironically, that experience (i.e. the Spanish American War) enhanced the prestige of the discredited 8-in gun. In the major naval battle, Santiago, the 13-inch guns made no hits at all, whereas the 8-inch made 13 (which was still a poor showing, as 319 rounds had been fired). "
  5. The article above address full salvo firing. In practice, many navies fired half salvos (e.g. The British in WWI typically fired all left guns & 30 seconds later fire all right guns). During the destruction of the German Battleship Scharnhorst in WWII, she returned fire alternating between forward and aft turrets. It is presumed that half salvos were a popular means of reducing mechanical shock of firing while providing fire control with more frequent opportunities for range correction.
  6. Circa 1900, there was much debate in the U.S. Navy concerning the effectiveness of 8inch turrets for battleships. Post Spanish American war evaluations indicated the 8 inch guns were effective. See American Battleships 1886-1923.
  7. While major powers all developed high velocity guns in imitation of the French, not all guns were created equal. Circa 1890, British gunnery practice was marred by frequent explosion of gun barrels. During the Russo-Japanese War, British built Japanese battleships had 4 of 16 gun barrels rupture (i.e. 12 inch guns) during the Battle of the Yellow Sea on 10 August.
  8. Richard B. Rank reports that Battleship Washington achieved 9 16inch hits on Battleship Kirishima while firing at 8400 yards. Kirishima also was hit approximately 40 times by 5inch shells. Other sources report that Washington fired a total of 56 rounds (source TBD).
  9. Circa 1900 rates of fire were quite low. During the Russo Japanese war (1904-05), Janes reports the "normal rate of fire" for Russian battleships as .3 rounds per minute. This is consistent with reports that Orel's magazines were exhausted of 12 inch shells following about 3 hours of firing. Note that Russian ships generally carried ~ 60-70 rounds per gun for the main batteries, whereas the British built Japanese battleships carried 80 rounds per gun.
  10. Julian Corbett indicates that during the Aug 10, 1904 battle between Russian and Japanese battleships, the Japanese fired under turret commander control, which was traditional. By the Tsushima Battle 8 months later, the Japanese had retrained for salvo firing of main batteries. Captain Semonoff (see Corbett's book) reports that the volume of hits was stunning and quit unlike it had been 8 months earlier.
  11. T. Ropp, Development of a Modern Navy, Naval Institute Press
  12. Edited by Benjamin F. Armstrong, 21st Century Sims, Naval Institute Press (c) 2015
  13. Ongoing research by Paul F. Watson will hopefully provide a reasonable basis for asserting percentage hits by Russian and Japanese forces during the August 10, 1904 sea battle in the Yellow Sea. When completed, an article explaining the conclusions & basis is intended.
  14. Sims went so far as to write a letter to President Roosevelt on finding that needed gunnery reforms were stonewalled by the " navy establishment". Roosevelt put him in charge of reforming U.S. Navy gunnery and he proved very effective.
  15. Garzke and Dulin in Allied Battleships of WWII (pp180) state that Bismarck fired a salvo at 16500 yards hitting hood and penetrating the magazines. Total number of rounds fired during the battle was not great, and thus Hood took very few hits.

References:

  1. Warship International, Jurens the Evolution of Battleship Gunnery in the U.S. Navy, 1920-1945
  2. Peter Padfield, Guns at Sea
  3. Numerous books by Garzke
  4. U.S. Battleships by Milton Friedman, U.S. Naval Institute Press, (c) 1985.
  5. Graduate Report in Lieu of Thesis, by David R. Watson, U.T. Austin
  6. Witnesses of Tsushima by J. N. Westwood. Sophia University Press, (c) 1970
  7. The Fighting at Jutland by John Campbell
  8. The Development of a Modern Navy by Theodore Ropp. U.S. Naval Institute Press (c) 1987
  9. American Battleships 1886-1923 by John Reilly, Jr. & Rob ert L. Scheina, Naval Institute Press (c) 1980
  10. History of United States naval Operations in World War II, Samuel Eliot Morison, Little, Brown & Company (c) 1988
  11. British Battleships 1889-1904 by R. A. Burt, U.S. Naval Institute Press
  12. Guadalcanal by Richard B. Frank, Penguin Books, (c)1990
  13. 21st Century Sims, Edited by Benjamin F. Armstrong (c)2015
  14. Maritime Operations in the Russo-Japanese War, Julian S. Corbett
  15. Yellow Sea Battle Rev B by Paul F. Watson. Request report from www.dionysus.biz



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