A replica Nordenfelt four-barrelled anti-torpedo boat gun mounted on the Victorian sloop HMS Gannet in the Historic Dockyard, Chatham. Gannet carried eight of these Nordenfelts, four on each beam, in addition to her QF guns. One of Gannet’s Nordenfelts has been restored to firing condition. (Photo by the author, courtesy of Scott Belcher)
A Nordenfelt four-barrelled 1in anti-torpedo boat gun, taken from a contemporary sales brochure — the last thing seen by a reckless torpedo-boat crew, in the mind of the salesman. The gun was fired by pulling back and pushing forward the lever held by the gunner on the left. Each movement of the lever chambered and fired four rounds at a time, thus the gun fired in a continuous series of salvoes. In a separate illustration the gunner on the left is depicted as wearing a cutlass, in the hope of warding off a boarding party, an anachronism in that era of rapid-firing machine guns. The sailor on the right is traversing and elevating the mounting, which would be difficult to accomplish by one man also working the firing lever.
French battleship Jauréguiberry at speed, showing her large military masts which, in conjunction with her extreme tumblehome, had a serious effect on stability.
QUICK-FIRING CANNON
All too soon these upgraded rapid-fire machine guns were felt to lack sufficient punch to guarantee disabling or sinking an attacking torpedo boat, so attention switched to small-calibre cannon capable of firing a decent high-explosive shell, or just as useful, a solid armour-piercing shot. To give these weapons the firepower necessary to engage a rapid target, they were made quick-firing, using fixed rounds, with semi-automatic breech blocks which ejected the fired case and closed when a new round was inserted. Free-swinging, pointed by pushing against the shoulder rest, they gave the gunner a reasonable chance of hitting and disabling an opposing torpedo boat.
Because the latter would be unlikely to attack singly, batteries of QF anti-torpedo boat guns sprouted on the broadsides of most warships. Weight considerations restricted them to main- or weather-deck mountings, so to be able to carry anti-torpedo boat armament higher in the ship an interim weapon was introduced, the multi-barrel rotary cannon. Patented by Hotchkiss in 1885, the five-barrelled cannon at first sight resembled the earlier Gatling, but its mechanism differed in having only one firing pin for all five barrels, compared to the Gatling’s arrangement of a firing pin in each barrel (the Hotchkiss fired each barrel in turn at the 5 o’clock position). Also hand-cranked, the Hotchkiss naval revolver came in 37mm, 47mm and 53mm calibres, firing at up to forty rounds per minute. The ejection port was long enough to eject a complete round if one misfired, thus clearing the gun and avoiding a jam. One unfortunate side effect of this arrangement was that if a round merely hung fire, the live cartridge with its fizzling primer was ejected and landed at the feet of the unfortunate gunner.
Maxim belt-fed 37mm pom-pom on the training ship USS Hartford. The weapon gained its name during the Second Boer War, due to the sound it made when firing. (Naval Historical Foundation)
A later development was the fully automatic Maxim pom-pom, also in 37mm calibre. Although an impressive weapon, firing at up to two hundred rounds a minute, for the same weight and price the navy could mount the much more destructive 6pdr QF gun. As the torpedo boat developed in size and power, and its weapon added speed and distance, so the range of early single-shot QF guns developed to match: from the 1pdr (Driggs Schroeder), through 3pdr and 6pdr (Nordenfelt, Driggs Schroeder), 37mm, 47mm, 53mm and 57mm Gruson, the French 65mm, and the 3in (or 12pdr) as mounted on HMS Dreadnought of 1906. German predreadnoughts carried slightly larger anti-torpedo boat guns of 8.8cm calibre.
FIRING TRIALS
Many firing trials were carried out to discover the comparative value of the competing anti-torpedo boat QF guns, including at Portsmouth, St Petersburg, Copenhagen, La Spezia, and on the Gruson range in Germany.
In May 1880 comparative test firings were carried out at Portsmouth, using full-size model torpedo boats as the targets. The weapons tested were the 1in Nordenfelt firing solid shot and the 37mm Hotchkiss revolver, firing shell. The results were publicised in 1884 by Thorsten Nordenfelt in a large marketing brochure describing his weapons. The somewhat unrealistic tests were carried out at distances from 1500yds down to the suicidally close range of 100yds, by which time either the riddled torpedo boat would have sunk, or its torpedoes would have found their mark. The Hotchkiss jammed on the fourth run, much to Nordenfelt’s delight, the cause given being ‘lack of propellant’ in one cartridge case, the primer having forced the shell into the barrel — an embarrassing failure during an important test. Between 600 and 100yds range, the Nordenfelt scored 115 times out of 135 rounds fired, the Hotchkiss 36 times out of 50. Importantly, the mock-up engines in both targets were demolished.
Rapid-fire anti-torpedo boat guns of 37mm, 47mm, 53mm, 57mm and 82mm on shipboard mountings on the range at Tangerhütte were tested by the assembled guests, who took turns to aim and fire, mark the target at the butts and take measurements of the muzzle velocities. A special event was the rapid firing of 2kg (4.4lbs) armour-piercing shot against a mock-up of a torpedo boat bow section, placed 500m (545yds) from the 53mm/L39 gun. The mock-up was constructed with sides and bulkheads of Bessemer 8mm plate, with the 12mm-thick rear plate simulating a boiler. The gun was loaded and fired at a rate of thirty rounds a minute.
Although fired under ideal conditions, in daylight with no pitching or rolling of the static gun platform, against a stationary target at a known range, the results were nevertheless impressive. Given that the foreign and German guests were all experienced artillery officers, all thirteen shots fired in rapid succession were hits. Six shots deformed the hull plating, seven pierced the hull and internal bulkheads, and two pierced the ‘boiler’ as well. Despite the fact that the firing did not take place under the stress of actual combat, it can be imagined that each firer was under severe peer pressure to do as well as his companions.