| Cannone da 135/45 OTO 1937 and 1938, Ansaldo 1938 | |
|---|---|
| Type | Naval gun |
| Place of origin | Italy |
| Service history | |
| In service | 1940 - 1972 |
| Used by | Kingdom of Italy |
| Wars | Second World War |
| Production history | |
| Designer | Odero Terni Orlando |
| Manufacturer | Odero Terni Orlando Ansaldo |
| Specifications | |
| Mass | 6.01 t (13,200 lb) |
| Length | 6.075 m (19 ft 11.2 in) |
| Shell weight | AP and HE: 32.7 kg (72 lb) |
| Caliber | 135 mm (5.3 in) |
| Elevation | -5° to +45° |
| Rate of fire | 6-7 rounds per minute |
| Muzzle velocity | 825 metres per second (2,710 ft/s) |
| Maximum firing range | 19,600 m (21,400 yd) |
TheCannone da 135/45 OTO 1937 was a 135 mm (5.3 in) 45-caliber naval gun built for theRegia Marina in the late 1930s. Built as a response to the FrenchCanon de 138 mm Modèle 1929, it was meant to have the same range as the widespread120 mm gun, but with less muzzle velocity and less dispersion.[1]
This gun was of loose barrel, jacket and bracket ring, with a horizontal, hand-operated sliding block. The mountings, all with individual cradles for each gun, were either triple (on battleships) or double, with electrical-powered ramming (which, however, was too weak for elevations above 30°, which therefore required hand loading, which rendered the gun unsuitable for anti-aircraft use).[2]
The gun fired both AP and HE shells, all weighing 32.7 kg (72.1 lb), at a muzzle velocity of 825 M/S (2,707 F/S).
The triple mountings were used on theAndrea Doria-class battleships as a secondary battery (with each having four turrets); four double mountings each were fitted on the three completedCapitani Romani-class cruisers. Single shielded mounts were used to rearm thePremuda (captured Yugoslav destroyer Dubrovnik) andSpalato (captured Yugoslav destroyer Split) while others were built for the never completed aircraft carrierAquila andComandanti Medaglie d'Oro-class destroyers. Studies for twin dual-purpose mountings were begun, intended for the two unfinishedEtna-class cruisers and the salvaged battleshipConte di Cavour, but this work was still far from finished in 1943.[3]
The gun proved successful (having only a quarter of the dispersion of the 120 mm gun); however, with the 45° maximum elevation and the limit for mechanical ramming being at 30°, it could not be used against aircraft.[4][3]
After the war, when the light cruiserGiuseppe Garibaldi was rebuilt in 1961 as amissile cruiser, its original 152 mm turrets were removed, and two new 135 mm double DP turrets were fitted.[5]