RML 17.72 inch gun
| RML 17.72 inch gun | |
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| General Information | |
| Military designation: | RML 17.72 inch gun |
| Manufacturer designation: | RML 17.72 inch gun |
| Manufacturer country: |
 United Kingdom
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| Developer / Manufacturer: | Elswick Ordnance Company |
| Development year: | 1874 |
| Production time: | 1874 to 1883 |
| Number of pieces: | 15th |
| Weapon Category: | cannon |
| Team: | 35 |
| Technical specifications | |
| Overall length: | 9,953 |
| Pipe length: | 20.5 caliber / 9.226 |
| Caliber : |
17.72 inch (450 mm) |
| Number of trains : | 28 (polygonal) |
| Cadence : | 0.2 rounds / min |
| Elevation range: | 10.5 degrees |
| Side straightening area: | 150 |
| Furnishing | |
| Sighting device : | optically |
| Charging principle: | Muzzle loader |
The RML 17.72 inch (450 mm) gun ( 100-ton gun = 100-ton cannon ) was a muzzle-loading gun developed and manufactured by the Elswick Ordnance Company . It was used at the Regia Marina on two battleships and in coastal fortifications in Malta and Gibraltar .
history
In the 1870s, the RML 12.5 inch 38 ton gun was the largest gun made in Britain . With a mass of 36.8 t it fired shells with a weight of 271 kg. These penetrated 414 mm of steel at a distance of 1,800 m. This cannon met the requirements at the time of its creation, but advances in weapon technology are developing very quickly. Guns with a caliber of 420 mm and a weight of 76 t were very soon developed in France. The Royal Navy therefore requested a larger cannon weighing 81 t. Armstrong, the UK's leading manufacturer of artillery weapons, then began developing an even larger 457 mm caliber weapon, also known as the 100-ton cannon . However, the Royal Navy rejected this project as too difficult and costly.
After the unification of Italy, the Regia Marina Italiana started a demanding program to build the most powerful battleships of their time. The first to be built was the Caio Duilio class with 380 mm guns in 1873 . However, the Royal Navy began building the Inflexible with 406 mm guns in February 1874 . The Italian naval command then demanded stronger armament for the Caio Duilio class. Armstrong was ready to deliver a total of eight 450mm caliber guns. This enabled the Caio Duilio and her sister ship Enrico Dandolo to be equipped. The supply contract was signed on July 21, 1874.
This treaty shocked the British naval leadership. At the time, Malta was the most important British naval base in the Mediterranean after the Suez Canal . Malta had a number of coastal fortifications, but the largest guns were 320 mm. A defense against a possible attack by ships of the Caio Duilio class did not appear to be very promising. It was feared that the Italian ships could break through to the ports of Valletta and from there destroy the British fortifications one by one while they were out of the effective combat range of the British artillery. Corresponding requirements of the British Army were largely ignored by the bureaucracy in London . When the Caio Duilio was launched in 1876, no decision had been made regarding this problem.
Amazingly, the British government had not banned the sale of the weapons, which were consequently manufactured and delivered in accordance with the contract.
At the time, the Royal Navy was paying more attention to this issue due to demands from the Army. They demanded a gun that could penetrate around 900 mm of steel at a distance of 900 m. As a result, several designs for guns weighing 163, 193 and 224 tons were submitted. In December 1877, John Lintorn Arabin Simmons, as inspector general of the fortifications for the fortifications on Malta , demanded a total of four guns that could fight the Caio Duilio at a distance of 2700 m. Since the sea trials of the Caio Duilio had already started in the same year, the projects for the superheavy guns were finally abandoned and the decision to buy the 450 mm guns from Armstrong was decided. This seemed justifiable since a stationary battery had tactical advantages over an attacking ship.
Four guns were ordered in March 1878 and construction began in August 1878.
construction
The guns were the largest of their kind at the time. The RML 17.72 inch gun was a muzzle loader . First the propellant charge was inserted from the front , then the projectile in the same way. The tube had 28 polygonal lines . The cannon was 9,953 m long in total. The largest diameter was 1.996 m and tapered at the mouth to 735 mm. The tube was 9.22 m (20.5 caliber) long. The construction of the jacket pipe was complicated, it consisted of several, mutually overlapping rings. Firing was possible electrically or mechanically, with the help of optics. Three types of grenades could be fired:
- Armor piercing grenades (armor piercing - AP ), 1.12 m long, with a steel projectile tip and 14.5 kg explosive charge, penetration power 530 mm steel at 1,800 m
- High explosive grenades (High explosive - HE ), 1.232 m long, with 35 kg explosive charge and thinner walls
- Shrapnel projectiles, 1.143 m long, 2.3 kg with explosive charge and 920 shrapnel, each 110 g
All grenades weighed 910 kg each and could be equipped with a time fuse.
The propellant charge consisted of black powder. A propellant bag had a diameter of 399 mm, was 368 mm long and weighed 51 kg. Usually four or five bags of propellant charges were inserted.
The rate was one shot every five minutes. The maximum combat range was 5,990 m with the highest load and pipe elevation, 394 mm of steel could still be penetrated. The belt armor of the Duilio was 546 mm thick, the turrets were armored with 432 mm.
The gun did not have a barrel return mechanism . A special carriage construction was necessary to absorb the forces of the recoil . The lower mount was rotatably mounted on a solid base. A carriage with 18 wheels was placed on this lower carriage, which took the trunnion of the cannon. The car's path was inclined 4 degrees to compensate for the recoil. The car ran back 1.75 m. Two hydraulic dampers at the rear of the lower mount limited the way of the car and absorbed the remaining recoil forces. This construction was also known as the Vavasseur slideway . The car weighed 20,680 kg, the lower mount 24,118 kg and the base 2,032 kg. A hydraulic system for side and height was used for straightening.
The crew consisted of 35 men, of which 18 were needed for the ammunition.
Structure of the pipe
Grenade, caliber 17.72 inch
Twin gun turret of the Duilio
RML 17.72 inch in Gibraltar
RML 17.72 inch in Gibraltar
Fire and reload, model replica
commitment
A total of 15 guns were manufactured between 1874 and 1883. Eight of these were used as naval guns on the Duilio-class ships, another example served as a coastal gun in the Italian port of La Spezia , and the Italian Navy procured two more guns as reserves. The Royal Navy, which was responsible for the coastal fortifications in the United Kingdom, the colonies and the Dominions, procured a total of four guns for these purposes.
Ship gun
On March 5, 1880, a Caio Duilio gun was destroyed while firing with maximum charge. The maximum load was then reduced from 225 kg to 204 kg. The Caio Duilio was decommissioned in 1906, the Enrico Dandolo modernized in 1898, used in the Italo-Turkish War of 1911/12 and continued to be used until 1920.
Coastal gun
The adaptation of the gun as a coastal gun was not particularly successful. It took about three hours until enough steam pressure was built up and the weapon was ready for action. The steam pressure was necessary to align the weapon. Also the effective range to endanger an armored warship was only about 1.6 km.
Gibraltar
Guns of this caliber were also required for the fortifications of Gibraltar. Then two of the guns intended for Malta were delivered to Gibraltar. Work on the batteries began in 1878. First, the Napier Battery was installed in Rosia Bay in 1883. The Victoria Battery followed a kilometer further north in 1884. At this point the Caio Duilio had already been in service for seven years without closing the void in Malta's defense. The cannons themselves were delivered on the Stanley , a specially converted transport ship, in December 1882 and March 1883 and were deployed in July and September 1883. The first test shooting took place in 1884. However, due to problems with the hydraulic systems, the batteries were not fully operational until 1889.
The cannon in the Napier Battery was destroyed during a shooting ( gunfire ). The reason was the operator's attempt to cut the rate of fire in half from 5 minutes to 2.5 minutes. Repair was not possible. Since the Napier Battery was tactically more important, the last gun was moved from the Victoria Battery to the Napier Battery and the destroyed cannon was used as the foundation for a building.
The cannon was decommissioned in 1906.
Malta
In Malta, the cannons were placed in the Rinella Battery and the Cambridge Battery . The construction costs were £ 18,890 each, more than the cost of a cannon of £ 16,000. Although the construction of the batteries was already completed in 1884 (Rinella) and 1880 (Cambridge), the first cannon was only transferred to the Cambridge Battery on September 16, 1882 and erected there on February 20. The cannon of the Rinella Battery followed on July 31, 1883 and January 12, 1884. The trial shooting could not begin until 1885 because work was still to be done. Between 1887 and 1888, the operational readiness was restricted by problems with the hydraulic systems. Nevertheless, the weapons were judged to be quite reliable overall.
Both batteries were constructed identically. Below and behind the firing position were two ammunition bunkers and the drive for the hydraulic systems. With the two ammunition bunkers it was possible to load the weapon alternately and to fire two shots within 6 minutes.
For loading, the cannons were withdrawn from their firing position, the barrel was lowered and swiveled 90 degrees to the right or left to the side. The pipe was then loaded from the front from a bunkered charging station. 250 kg of propellant charge and the projectile were pressed into the barrel with a hydraulic ram. The tube was then turned again and moved back into the firing position.
A combat set of all three available types of grenade was supplied with the weapon, including 50 HE and 50 AP each. The shrapnel were no longer replenished after the shooting because they were considered to be ineffective.
The lateral directional range in the fixed firing positions on Malta was 150 °, the gun mounts used allowed a tube elevation of a maximum of 10.5 °.
The cannons were decommissioned in 1906, although they were last fired in 1903 and 1904. Reactivation was considered during World War I when the islands were threatened by the Goeben operating nearby . Compared to the modern armament of the Goeben , the range and cadence were completely inadequate.
The Malta gun is fired once a year for national celebrations, which is currently not possible due to a gun defect. For this purpose, a 100 kg would then powder - cartridge placed in the barrel - would deliver the enough energy to a 1000 kg explosive projectile to fire.
User states
literature
- Treatise on the construction and manufacture of ordnance in the British Service prepared in the Royal Gun Factory. 1887, London: Printed in Order of the Secretary of State of War.
- Text Book of Gunnery. 1887. London: Printed for His Majesty's Stationery Office by Harrison and Sons, St Martin's Lane.
- Text Book of Gunnery. 1902. London: Printed for His Majesty's Stationery Office by Harrison and Sons, St Martin's Lane.
- Charles Stephenson: The Fortifications of Malta 1530-1945. Osprey Publishing Limited, 2004. ISBN 1-84176-836-7
- Captain JM Wismayer: British Fortifications in Sliema (1814-1943). In: Kunsill Lokali Tas-Sliema: Lehen il-Kunsill Tieghek. 2007
- Sir Thomas Brassey: The British Navy, Volume II. London: Longmans, Green and Co. 1882
Web links
- NJM Campbell, British Super-Heavy Guns
- Text Book of Gunnery, 1887
- Treatise on the construction and manufacture of ordnance in the British Service, 1887
- (Gibraltar gun)
- Gibraltar gun, Museum of Gibraltar at gib.gi
Individual evidence
- ↑ Italy: 8 for Duilio and Dandolo, 1 for coastal defense (Spezia), 2 reserve. United Kingdom: 2 for Malta, 2 for Gibraltar; after Campbell, "British Super-Heavy Guns".
- ↑ a b c d Text Book of Gunnery, 1902. Table XII, Page 337
- ↑ Campbell, "British Super-Heavy Guns"
- ^ Leo Marriott, Simon Forty: Heavyweights: The Military Use of Massive Weapons , Verlag Book Sales, 2017, ISBN 9780785835493 , p. 92 [1]
- ↑ Captain JM Wismayer: British Fortifications in Sliema (1814-1943). In: Kunsill Lokali Tas-Sliema: Lehen il-Kunsill Tieghek. 2007
- ^ Brassey 1882, p. 95