Question on Italian 135mm and 65mm naval weapons

[ptdockyard]

The Navweps site on these two guns has some passing mentions that lead me to other questions:
-135 mm/45 (5.3") Models 1937 and 1938: There is this statement: "A twin AA version for the Etna class cruisers and for the rebuild of the damaged battleship Conte Di Cavour were only in the planning stages by the time of the Italian Armistice."

Does anyone have any information on this mount?

-65 mm/64 (2.56") Model 1939: This weapon was supposed to have an automatic loading feature that was abandoned: "The loading equipment was electrically powered and included dual loading trays and a pantograph linkage rammer. The rammer design proved troublesome and was finally abandoned in favor of slower, but more reliable hand loading. "

Even with hand loading this gun was to have a ROF of 20 rpm. Does anyone have information on the proposed autoloading equipment and what ROF that was supposed to have?

Interestingly, one of the 65mm prototypes was used on a German Trawler "Petsamo" of the 1.Transportflottille out of Genoa in 1945

 

[mirco1961]

Another picture. And no: as I know, there are not pictures of the automatic loading system for 65\64. Also a techical drawing show the manual reloading.

 

[mirco1961]

 

[mirco1961]

 

[mirco1961]

Above the barrel there were two recuperators, and the recoil movement guaranteed the functioning of the automatic loading system.
To cock the first shot there was a special lever, which was rotated backwards.
Two lateral positions were available for aiming the cannon, located behind the stepped shield, equipped with two large slits that opened by folding forward.
Some prototypes were made of the new cannon, and mass production began, but the automatic loading system with swinging arms was never developed.
The mechanism that aligned the projectile with the barrel and introduced it into the chamber proved to be unfeasible, as did the mechanism for adjusting the time fuze, which had to be done very quickly.

 

[mirco1961]

Cannone Automatico Ansaldo 65/64 mod 1939. Foto inedite archivio Ansaldo. - MILITARY STORY

Il famoso cannone Ansaldo 65/64 letto con le foto inedite dell’archivio Ansaldo. www.fotografiaeindustria.it/2020 Verso la fine degli anni trenta del XX secolo la Regia Marina avviò lo sviluppo di un nuovo tipo di cannone antiaereo ad altre prestazioni, con cui sostituire il precedenti pezzi da...

www.militarystory.org

 

[mirco1961]

For the 135, as I Know the twin AA version for the Etna class cruisers and for the rebuild of the damaged battleship Conte Di Cavour were only in the planning stages by the time of the Italian Armistice. The mount for the projected conversion in AA cruisers of the Di Giussano class will be the simple Capitani Romani mount.

 

[ptdockyard]

Thank you. So the loader system on the 65mm was not necessarily an “auto loader” like what was on the British 6pdr mounts used on MTBs.

On the 135mm, Bagnasco’s book on Italian Battlesips Cavour and Duilio said the 135mm for the Cavour were to be mounted in the existing secondary turrets after modifications. They have two photos showing these but no mention of the new mounts were DP.

I did not think about whatever twin mounts were being thought of for the proposed Di Guissano conversion.

Dave

 

[cattalonX]

 

[mirco1961]

Yes, but basically was the same gun of Capitani Romani class, in a different mount (and I don't know how well they worked....)

 

[Phoenix_jz]

FWIW, on the rate of fire of the 65mm/64, some background may be useful.

The program was announced in November 1938 original tender (set to expire on 30 March 1939) went out to four companies - Ansaldo, OTO, Isotta Fraschini, and Breda.

The original requirements called for a 65mm/60 with the following characteristics;

Mass: 580 kg
MV: 850 m/s
RoF: 30 rpm

The first gun system was supposed to be ready in December 1939, and the rest (total of 78 to be built, for the Capitani Romani) were all to be completed and delivered by the end of 1941.

The winners, Ansaldo, worked with Terni and initially produced a 65/56, which then grew to an /62 and finally /64. One source I have actually gives the rate of fire as 25-30 rpm, and a lower MV and range of 850 m/s and 6,300 meters - this may reflect the earlier lower-caliber length versions, versus the usually reported 950 m/s with a range of ~7,500 meters? The rate of fire seems to reflect what Ansaldo intended to achieve with the electrically powered automatic fuse loader and power rammer system. Ansaldo-Terni only began serial production in 1942, with 60 delivered by March 1943 and a total of 73 by July 1943.

It is also interesting to note that some information exists on the two other prototypes submitted. Breda's effort was a 65mm/58, evaluated in December 1940 and November 1941, had an MV of 850 m/s and a maximum elevation of +70°. These prototypes were rejected, and unfortunately I have no more information on them. Caproni (via their subsidiary Isotta Fraschini) also developed a 65mm/58, which was a stabilized model. The prototype apparently was only completed in 1943, but featured impressive performance - a 4.3 kg projectile fired at 850 m/s to a maximum range of 11,750 m, and a rate of fire of 50 to 55 rpm. It was, however, relatively heavy, with the entire system coming in at 7.25 tonnes (metric).