Pre-Dreadnought Medium Armament

This essay appears courtesy of Keith Allen (

Some have made the suggestion that the development of fire control systems was driven largely by the advent of medium-caliber quick-firing guns, which unlike heavy guns could be used at long range and with sufficient rate of fire to make spotting corrections practical. I questioned this correlation of quick-firers or medium guns to long-range engagement. I have taken a further look at the development of secondary batteries in predreadnought battleships, mainly in the U.S. and British navies; no disrespect is intended to the French, Italians, Germans, or the Russians, but most of my sources in this period are on the British and Americans.

There were four fairly distinct categories of guns on predreadnoughts

To define two basic terms before starting: A quick-firing (QF) or, in USN terms, a rapid-firing (RF) gun has a quick-acting breech mechanism and a metal cartridge case. The British term "BL," which initially meant breech-loader and in official terminology retained this meaning, subsequently came in reality to mean--and is used here to mean--a bag-loaded gun, as opposed to a QF gun.

British Battleship Secondary Armament, 1870-1902

While WARRIOR and her immediate successors had mixed batteries, by the early 1870s British battleships were built with single-caliber batteries; e.g. DEVASTATION, THUNDERER, and DREADNOUGHT, all laid down 1869-1870, had four 12-inch guns and no secondary battery as completed. The first mention I can find in Oscar Parkes's book of an anti-torpedo battery is in TEMERAIRE, laid down in 1873; unfortunately Parkes does not make a fuss about it or describe the origins of this battery. The giant INFLEXIBLE, laid down shortly afterward, had a battery of six 20 pdrs. which Parkes says were meant both for torpedo defense and as saluting guns.

The first medium-caliber guns in British battleships were fitted in AJAX and AGAMEMNON (both laid down 1876 and completed in 1883). These were equipped with two 6-inch bag-loaded (BL) guns, intended for use against the unarmored portions of enemy ships. In addition these ships had a light anti-torpedo battery, at least some of which was composed of 6 pdr Nordenfelt QF guns. In the space of a decade then, we have gone from a single-caliber to a three-tiered armament in British battleships.

In 1876 the Italians laid down their innovative ITALIA, with a raft-body construction and unarmored except for the redoubt housing the heavy guns. Her designer, Benedetto Brin, believed that no armor could protect a ship against heavy guns. ITALIA also had an unusually large secondary battery; she was designed with eighteen 6-inch, later changed to seven 5.9-inch and four 4.7-inch. Although these were apparently not quick-firers in the strict sense, they ironically foreshadowed the development of the fast-firing medium guns that would make Brin's own design obsolete, as an unarmored ship could be riddled to pieces by QF guns.

This implication of ITALIA's armament was recognized by British designers, and Parkes sees it as highly influential in the design of COLLINGWOOD, precursor to the "Admiral" class. "The prospect of having to face a heavy volume of fire from a numerous battery of secondary guns such as had been introduced in the ITALIA opened up entirely new problems in the matter of protection. These 6-in. B.L. [i.e. the 5.9 BLs on ITALIA] could not be used when the big guns were in action [presumably because of blast], and could only play their part against capital ships when the range had been closed. This meant that instead of concentrating armour to meet a very slow and uncertain fire at long range by big guns only, it had become necessary to devise a method of distribution" designed to ensure protection against heavy, medium, and light guns. [Parkes, pp. 299-300]

COLLINGWOOD (laid down 1880, completed 1887) introduced the 6-inch secondary battery in British battleships. These were still bag-loaded, not quick-firers. John Roberts says in "Conway's" that they were intended both for torpedo defense and for use against the unarmored portions of heavy ships; D.K. Brown, in "Warrior to Dreadnought" (p. 92) clearly states that the 6-inchers were for use against battleships, while torpedo defense was the mission of the 6-pdr and 3-pdr guns.

Parkes writes that the torpedo menace loomed very large in battleship design by the mid-1880s, and that the development of larger quick-firers was seen as a necessary counter to it. The first medium-caliber quick-firers in British battleships were fitted in NILE and TRAFALGAR (laid down 1886, completed 1890-1891). With their six 4.7-inch guns, "the torpedo menace began to assume its proper proportions" (p. 345). In the important ROYAL SOVEREIGN class of the 1889 program, the British advanced to a secondary armament of ten 6-inch quick-firers, along with sixteen 6-pdr and twelve 3-pdr.

D.K. Brown's interpretation of this QF armament differs substantially from that of Oscar Parkes. The 6-inch QF on ROYAL SOVEREIGN "was not an anti-destroyer weapon as in later Dreadnoughts but was intended to destroy the unarmoured structure of battleships" (p. 129). Subsequently he reiterates this point in saying of British battleship armament in 1893-1904 that "the secondary battery, usually twelve 6in, was intended to attack the unarmoured portion of enemy ships; 12pdrs and smaller were mounted to protect against torpedo boats. Many officers believed that the enemy would be disabled by such a 'hail of fire' and only then would the 12in guns fire, sinking the opponent with AP shots at close range" [p. 154].

This is the one statement I can find in support of the notion that the heavy guns were envisaged mainly for a close-range coup de grace, although it does not necessarily imply that the quick-firers were used at long range. Elsewhere Brown indicates that there was no difference in the ranges envisaged for 6-inch and 12-inch guns: "Prior to DREADNOUGHT the fighting range was about 3000 yds at which both the 6in and 12in could hit frequently. The generally-accepted view was that the enemy should be disabled by a hail of 6in fire, using HE shells and then sunk by AP shells from the 12in. The 6in 'secondary' armament was an important (to some the most important) weapon in fighting enemy battleships. Lesser guns, 12 pdr and and below, were provided to deal with torpedo boats."

The suggestion that medium-caliber, quick-firing guns were more amenable to spotting corrections than large guns, because in the case of the latter the target would move too far in the interval between shots for such adjustments to be effective. Brown actually takes precisely the opposite view. "As range increased, it became necessary to spot the fall of shot before firing the next round to correct range and deflection. It was this, more than anything, which led to the immense superiority of the big gun. The smaller gun, whose apparent advantage was in rate of fire, could not achieve this rate at longer range." Later he explains this more fully: "...the splashes from the 6in secondary armament merely obscured the more important splashes from the 12in. The need to spot the fall of shot and apply corrections before the next salvo meant that the effective rate of fire of a 6in at 6000yds was much less than that achieved in short-range target practice; in fact, as range increased, the rate of hitting by the 12in exceeded that from the 6 inch" [pp. 180-81].

U.S. Battleship Intermediate And Medium Armament

Norman Friedman, in his discussion of predreadnought armament in "U.S. Battleships," regards both the heavy and medium batteries of the day as essentially short-range weapons: "The mixed-calibre battleship designs of the turn of the century were quite logical, given slowly firing heavy guns whose limited accuracy demanded short battle ranges, RF guns that fired HE shells, and machine guns and machine cannon that were effective at the then-prevailing short battle ranges. The heaviest guns would try for hits of individually devastating effect on belt or on main battery. The lighter weapons would attack area targets, those less well- protected areas vulnerable only to great numbers of hits" [pp. 12-13].

U.S. battleship armament of the 1890s differed substantially from that of Britain and most other powers in the presence of an intermediate 8-inch battery, well before comparable guns became standard on European battleships. The first two U.S. battleships, MAINE and TEXAS (laid down 1888-1889, commissioned 1895), had 6-inch BL secondary batteries. But 8-inch guns were introduced in the subsequent INDIANA class (laid down 1891, commissioned 1895-1896) and became standard after that. The basic reason for this choice, Friedman believes, is that the United States could not yet manufacture the 6-inch QF guns that were installed in contemporary British battleships. The 8-inch gun could be used instead, to puncture the armor designed to defend against 6-inch fire. "This was not a happy choice. Eight-inch guns were heavy and cumbersome," and their rate of fire was not impressive--about one round every two minutes (see notes on rate of fire at the end of this tome). [pp. 12-13, 26-27]

After the INDIANAs, the one-of-a-kind IOWA and the KEARSARGE class were built with 8- inch guns--KEARSARGE and KENTUCKY with their peculiar arrangement of 8-inchers superimposed on the 13-inch turrets. By 1896, however, the U.S. Navy finally had developed a 6-inch QF gun, and decided to install it in place of the 8-inchers on the ILLINOIS class. The Bureau of Ordnance believed that the 6-inch would have a rate of fire three to five times greater than that of the heavier gun. The ILLINOIS and subsequent MAINE class had a secondary battery of 6-inch QF guns, and no eight-inchers.

While these ships were under construction, however, the Battle of Santiago restored the luster of the eight-inch gun. The 13-inch did not do well, nor did the 6-inch, although as Friedman notes the 6-inchers in the battle were of the old slow-firing type. The 8-inch guns were restored in the next class, the VIRGINIAs, which had four calibers of guns: 12-inch, 8-inch, 6-inch QF, and a 3- inch anti-destroyer battery. The stated rationale for the 8-inch guns was that it "was superior to the 6 inch because it could penetrate the 6-inch armor that shielded the secondary batteries of foreign battleships." The VIRGINIAs, like KEARSARGE, had the 8-inchers superimposed over the main battery, so that there was gross interference between the two. Furthermore, the 8- inchers apparently did not provide a sufficiently rapid fire to justify their existence. Friedman quotes a former CO of VIRGINIA as saying that "the great increase in the rapidity of fire of our heavy guns from, say, one shot in three minutes to three shots in one minute, virtually neutralized the advantage of having 8-inch guns," which constantly interfered with the big guns. The rate of fire of the 12-inch guns was surprisingly high, if this is accurate--faster than the 16-inch guns of a World War II battleship, which could get off about two rounds per minute. [Friedman, 4 1-43]

In its final two predreadnought types, the CONNECTICUT class and the small MISSISSIPPI and IDAHO, the U.S. Navy fitted an odd combination of 8-inch and 7-inch guns, dispensing with the 6-inch QF. "The board justified its retention of the 8-inch gun as necessary to pierce the medium armor which covered much of the upperworks of contemporary battleships. It considered the 7 inch the best possible rapid-fire weapon, capable of penetrating 7 inches of armor at 3,000 yards, that is, at battle range." The 7-inch was not actually a quick-firer in the strict sense, however.

Friedman's account suggests that the intermediate guns, like the 6-inchers, were not suited for long-range fire. In deliberations in 1903, leading eventually to the dreadnought, the Naval War College Staff noted that the torpedo danger would force ships to engage at 3,000 yards or more, and that at that range the 8-inch and 7-inch guns could not penetrate the armor covering the enemy's secondary battery--a major target of medium and intermediate guns. The destruction of enemy battleships required heavy guns; defense against torpedo attack required lighter, rapid-fire guns. The intermediate battery was not well suited to either role. [p. 53]

Intermediate Guns and the Last British Predreadnoughts

The United States Navy, as noted, adopted the intermediate battleship gun well before other nations, and after briefly abandoning it had restored the 8-inch gun by the turn of the century. At about this time, the intermediate gun made its appearance in British and other foreign battleships. The eight-ship KING EDWARD VII class (laid down 1902-1904, completed 1905-1906) had an intermediate battery of four 9.2-inch guns, along with ten 6-inch QF and 12-pdr and 3-pdr anti- torpedo batteries. British authors attribute the installation of the 9.2 to the example of NEW JERSEY (VIRGINIA class) and the Italian BENEDETTO BRIN. Oscar Parkes says that the 9.2 fired almost as quickly as the 6-inch, although some other figures contradict this (see next section). Improvements in armor and increases in battle range had made the 6-inch less effective. Most Royal Navy officers greatly favored the 9.2-inch, and believed the 6-inch to be superfluous in these ships. [Parkes, p. 427; Richard Burt, "British Battleships 1889-1904," pp. 229-38; unfortunately D.K. Brown doesn't say much about the advent of the 9.2, as best I can tell.]

In the final predreadnought class, LORD NELSON and AGAMEMNON, the 6-inch guns were eliminated, and the 9.2s increased to ten guns. The combination of 12-inch and 9.2-inch proved unhappy in practice, however, as it was virtually impossible to distinguish their splashes.

The trend toward intermediate battleship guns, begun in the United States and Italy, was copied in several navies besides the British. Russian battleships for some time had had a secondary armament of 6in/45s. In the EVSTAFI and IMPERATOR PAVEL classes, laid down in 1903-1904, the Russians adopted an 8in/50 intermediate battery. The Germans went from 150mm to 170mm in the seconary battery of their last predreadnoughts. The French increased their secondary battery from 6.4-inch to 7.6-inch in the LIBERTE class, laid down in 1902-1903.

A Note on Rates of Fire

Friedman provides rates of fire for some U.S. battleship guns in "US Naval Weapons," p. 17. He notes that while quick-firing guns brought a great increase in rate of fire, subsequent improvements in training and materiel also substantially improved the rate of fire of bag guns; one such step was the adoption of smokeless powder, which did not leave the extensive residue deposited by black powder, which required the bore to be cleaned after every round. Figures for 1897 and 1907 are:
Gun 1897 1907
6in/40 BL one round every 90 seconds one round every 8.2 seconds
6in/40 RF one round every 40 seconds one round every 7.9 seconds
8in/35 one round every two minutes two rounds per minute
12in/35 one round every five minutes one round every 51 seconds (that one round per 20 seconds claimed by the VIRGINIA's captain did seem a little optimistic).

Friedman notes in reference to the 6-inch that by 1907 the gap between BL and RF rates of fire had narrowed greatly. Note, though, that the intermediate 8-inch gun still had a low rate of fire.

D.K. Brown (p. 156) quotes Jellicoe's 1906 figures for rates of fire in gunlayers' tests and in battle practice, and notes that the latter figures corresponded well to those actually attained by the Japanese at Tsushima:
Gun Gunlayers Battle Practice
6-inch 12 rounds per minute 4 rounds per minute
9.2-inch 5 rounds per minute 2 rounds per minute
12-inch 2 rounds per minute one round per minute

Note again that the rate of fire of the intermediate gun is not dramatically better than for the heavy gun.


A review of the data does not support my initial belief that the big guns of predreadnoughts were meant for relatively long ranges; nor do my sources support the theory that medium or intermediate-caliber guns were intended for action at longer ranges than the heavy guns, although perhaps Russian or other sources would present a different picture. It would appear that the heavy and intermediate guns of the late predreadnought era were intended for action at similar ranges, about 3,000 yards, and that in practice the rate of fire of the 8-inch or 9.2-inch gun was not sufficient to riddle the upperworks of an enemy with rapid fire; these guns were a compromise, and probably not a very good one, between the heavy, slow-firing 12-inch gun and the rapid-fire 6-incher. The 6-inch quick-firers were originally intended primarily to shred the upperworks of enemy heavy ships, not to counter enemy torpedo boats as I had suggested. But these medium batteries lost their effectiveness in this role as ranges increased, and by the early dreadnought era these weapons had become primarily anti-destroyer guns.

Last Updated: 12 July, 1999.

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