The EOC 8 inch 45 caliber were a family of related  45 caliber naval guns designed by the Elswick Ordnance Company and manufactured by Armstrong for export customers before World War I.  In addition to being produced in the United Kingdom licensed variants were produced in Italy and in Japan.  Users of this family of gun included the navies of Argentina, Chile, China, Italy, Japan and Spain.  This family of guns saw action in the Spanish–American War, Boxer Rebellion, Russo-Japanese War, Italo-Turkish War, World War I and World War II.  In addition to its naval role it was later used as coastal artillery and siege artillery after the ships it served on were decommissioned.

History
The EOC 8 inch 45 caliber family of guns originated in 1894 from the Elswick Ordnance Company Pattern Q gun which was first produced for export in 1895.  In addition to the Pattern Q there were S, U and W Pattern guns produced for export.  Earlier Patterns A through P, R and T were shorter 35 or 40 caliber guns.  While the Pattern Q, S, U and W were all 8 inch 45 caliber guns.  The weights and dimensions of each Pattern of gun were similar and their ammunition, bagged charges and their ballistic performance were also similar.

Construction
The Armstrong Pattern Q was the first wire wound 8 inch EOC gun.  I was constructed of an inner A tube, wire wound for , with a jacket shrunk over the wire.  It had a single-motion breech mechanism of cylindrical-conical style with five threaded and five smooth sectors.

Naval service
The Japanese 20.3 cm/45 Type 41 naval gun was based on the Pattern S guns from Armstrong first installed on Takasago in 1898 with licensed production beginning in 1902.  Existing S, U and W Pattern guns were later classified as Type 41 naval guns in Japanese service.  Type 41 guns were employed as Coastal Artillery during World War II after the ships they armed were decommissioned and disarmed.  Pattern S guns also armed protected cruisers of Argentine Navy and Chinese Navy.

Pattern S
  - This protected cruiser was completed in 1896 by Armstrong in Newcastle upon Tyne for the Argentinian Navy. The primary armament was two Pattern S guns mounted on single, shielded, pedestal mounts fore and aft.
 Hǎi Qí class -  The two protected cruisers of the Hǎi Qí class were completed in 1899 by Armstrong for the Chinese Navy.  The primary armament of the class were two Pattern S guns mounted on single, shielded, pedestal mounts fore and aft.
  - The two protected cruisers of the Kasagi class were built in the United States for the Imperial Japanese Navy.  was built by William Cramp & Sons in Philadelphia and completed in 1898, while  was built by the Union Iron Works in San Francisco and completed in 1899. The primary armament of the class were two Pattern S guns mounted on single, shielded, pedestal mounts fore and aft.
  - This protected cruiser was completed in 1898 by Armstrong for the Imperial Japanese Navy. The primary armament was two Pattern S guns mounted on single, shielded, pedestal mounts fore and aft.

Pattern U guns from Armstrong armed both Japanese and Chilean protected and armored cruisers.

Pattern U
  - The two armored cruisers of the Asama class were completed in 1899 by Armstrong for the Imperial Japanese Navy.  The primary armament of the class were four Pattern U guns mounted in twin gun turrets fore and aft.
  - This armored cruiser was completed in 1900 by Ateliers et Chantiers de la Loire, Saint-Nazaire, France for the Imperial Japanese Navy.  The primary armament was four Pattern U guns mounted in twin gun turrets fore and aft.
  - This protected cruiser was the sister ship of Takasago and completed in 1902 by Armstrong for the Chilean Navy. The primary armament was two Pattern U guns mounted on single, shielded, pedestal mounts fore and aft.
  - The two armored cruisers of the Izumo class were completed in 1900-1901 by Armstrong for the Imperial Japanese Navy. The primary armament of the class were four Pattern U guns mounted in twin gun turrets fore and aft.
  - This armored cruiser was completed in 1900 by AG Vulcan Stettin, Stettin, Germany for the Imperial Japanese Navy.  The primary armament was four Pattern U guns mounted in twin gun turrets fore and aft.

The Italian Cannone da 203/45 Modello 1897 was based on the Pattern W gun from Armstrong and licensed production began in 1897 at the Armstrong factory in Pozzuoli, Italy.  The Modello 1897 guns armed ships built in Italy for the Argentinian Navy, Italian Navy, Imperial Japanese Navy and the Spanish Navy.  Modello 1897 guns were later employed by the Italian Army as Siege Artillery during World War I and as Coastal Artillery during World War II after the ships they armed were decommissioned and disarmed.

Pattern W
  :** One of the four Giuseppe Garibaldi-class armored cruisers built for the Argentinian Navy,  had four Pattern W guns as primary armament mounted in twin gun turrets fore and aft.
 The three Giuseppe Garibaldi-class armored cruisers built for the Italian Navy had a primary armament of one Armstrong Pattern R 10 inch gun in a single turret fore and two Pattern W guns mounted in twin gun turrets aft.
 There were two  armored cruisers built for the Imperial Japanese Navy.  had a primary armament of one Armstrong Pattern R 10-inch gun in a single turret fore and two Pattern W guns mounted in a twin gun turret aft.  had a primary armament of four Pattern W guns mounted in twin turrets fore and aft.
 The single Giuseppe Garibaldi-class armored cruiser built for the Spanish Navy, , was designed to have a primary armament of one Armstrong Pattern R 10-inch gun in a single turret fore and two Pattern W guns mounted in a twin gun turret aft. However the 10-inch gun was found to be defective and was not installed.
 Iwami - This ship originally Oryol of the Imperial Russian Navy and was a war prize from the Russo-Japanese War. In 1907 the ship's original secondary armament of twelve 6-inch guns, mounted in twin turrets, amidships were replaced by six, single gun, shielded, pedestal mounted, Pattern W guns.
  - The four semi-dreadnought battleships of this class had a secondary armament of twelve Pattern W guns, in three twin gun turrets per side, amidships.
  - The two pre-dreadnought battleships of this class had a secondary armament of four Pattern W guns mounted in casemates amidships in the ships superstructure.

Italian Army use
As the First World War settled into Trench Warfare on the Italian Front the light field guns that the combatants went to war with were beginning to show their limitations when facing an enemy who was now dug into prepared alpine positions. Indirect fire, interdiction and counter-battery fire emphasized the importance of long-range heavy artillery.  In order to address the Italian Army's lack of long range heavy artillery surplus 203/45, 254B, 254/40, 305/17, 305/40, and 305/46 Naval Guns were converted to land use.

These guns were mounted on De Stefano carriages for land use and the resulting guns were classified by their size in millimeters 203, their length in calibers 45 and lastly by their carriage type DS which stood for De Stefano or 203/45 DS.  The De Stefano carriage was a clever, but strange looking monstrosity which looked something like a large steel basket with the gun barrel mounted towards the rear of the carriage.  The carriage was a large box-trail design with four non-steerable wheels.  The wheels were fitted with detachable grousers designed by major Crispino Bonagente for traction on soft ground and was towed in one piece by a Pavesi-Tolotti artillery tractor.

When not on the move the grousers were removed and the steel wheels rode on an inclined set of steel rails when in firing position.  The steel rails were mounted on a firing platform made of wooden beams which allowed the gun 360°of traverse.  When the gun fired recoil which was not absorbed by the recoil mechanism was transmitted to the wheels and the carriage rolled up the inclined rails and then rolled back into firing position.  The box trail carriage was tall and wide enough that the breech of the gun was accessible at high angles of elevation without a pit being dug and the gun crew had a bucket and hoist for ammunition handling.

Photo Gallery

Notes

References

External links 
 http://www.navweaps.com/Weapons/WNIT_8-45_EOC.php
 http://www.navweaps.com/Weapons/WNJAP_8-45_EOC.php

 

203 mm artillery
World War I naval weapons
Naval guns of Italy
Naval guns of Japan