On Italian 203mm/55 guns

[GianmarcoBianchi]

such guns project was in mid-1930s. said to be modified from old 10 inch guns.
In Ansaldo progetto 986 for Spain, there was 203mm/55 guns mentioned.
In Warship 2023? maybe, there was description that the gun was a stopped project. About its probable performance, is there any info and reference?

 

[YourChair]

From what I know, that's basically all the information that's available: the first batch of these guns were to be rebored from old 254mm guns lying around, and they were intended for cruiser designs in the 30s

apparently there was also a notional 203mm/55 gun intended for export designs (for example to latin america), but I don't know if anything was decided

Assumedly this cannon in its final form would be evolved from the earlier 203/53, and have similar characteristics to the 152mm/55 guns mounted on the Littorios and the late 1930s cruisers (including some that never left the design table), just at 203mm caliber

 

[Phoenix_jz]

Yes, you're probably thinking of Cernuschi and O'Hara's article on the Breakout Fleet in Warship 2006 rather than 2023 This contains a reference to a 203/55 rebored from 254/45's - though I believe this may be more in reference to a prototype gun given the wording and the sheer lack of available guns. Even with spares the RM would not have had enough old 10" guns to arm more than one ship with a 203/55's built from the 254/45 (assuming 8-9 guns per ship).

More specifically, the text reads:

An analogous decision took place in January 1936 when the Navy decided to forgo development of a new 203/55 (re-bored from the Old Armstrong Model 1908 weapons of the Italian armoured cruisers) for the envisaged new big cruisers, adopting instead the successful semi-automatic 152/55 with enhanced turret automation.

From "The Breakout Fleet: The oceanic programmes of the Regia Marina", by Enrico Cernuschi & Vincent P. O'Hara, in Warship 2006, pg.91.

They also mention a 203/55, presumably the same gun, being offered to Spain in 1939 from a 10,500-ton cruiser, and, though not mentioned by the article, it was also offered with the IX-203 variant of the three large cruisers offered to Spain in 1940.

Ansaldo's digitized photo archives do actually have a 203/55 gun, which is labelled as a "203/55 Naval Cannon - Chile - in Three-Gun Turrets." from 1937.

The barrel weight is placed at 15.2 tonnes (no breech assembly), firing a 120 kg projectile at 940 m/s with a 47.3 kg charge. Working pressure is 3,200 kg/cm^2.

I would have to guess - particularly with the reference to three gun turrets - that this would be the same gun as offered on the above cruiser. Which is interesting, because the Ansaldo schematics clearly indicate it is for Chile, and I am not familiar with any 203mm ships offered to Chile in this period.

It is also interesting to note that the shell here is somewhat lighter than the RM's preferred 203mm projectile, which was 125.3 kg.

 

[awhalen61]

I would have to guess - particularly with the reference to three gun turrets - that this would be the same gun as offered on the above cruiser. Which is interesting, because the Ansaldo schematics clearly indicate it is for Chile, and I am not familiar with any 203mm ships offered to Chile in this period.

I would expect this is likely due to the 1937 Chilean attempt to purchase heavy cruisers, as their initial specification was for an 8600 ton cruiser with two triple 203mm turrets. Friedman has written about the British cruiser offers which resulted from this attempt, but I've never seen details on a completed Italian offer from that series.

 

[GianmarcoBianchi]

Yes, you're probably thinking of Cernuschi and O'Hara's article on the Breakout Fleet in Warship 2006 rather than 2023 This contains a reference to a 203/55 rebored from 254/45's - though I believe this may be more in reference to a prototype gun given the wording and the sheer lack of available guns. Even with spares the RM would not have had enough old 10" guns to arm more than one ship with a 203/55's built from the 254/45 (assuming 8-9 guns per ship).

More specifically, the text reads:



From "The Breakout Fleet: The oceanic programmes of the Regia Marina", by Enrico Cernuschi & Vincent P. O'Hara, in Warship 2006, pg.91.

They also mention a 203/55, presumably the same gun, being offered to Spain in 1939 from a 10,500-ton cruiser, and, though not mentioned by the article, it was also offered with the IX-203 variant of the three large cruisers offered to Spain in 1940.

Ansaldo's digitized photo archives do actually have a 203/55 gun, which is labelled as a "203/55 Naval Cannon - Chile - in Three-Gun Turrets." from 1937.

The barrel weight is placed at 15.2 tonnes (no breech assembly), firing a 120 kg projectile at 940 m/s with a 47.3 kg charge. Working pressure is 3,200 kg/cm^2.

I would have to guess - particularly with the reference to three gun turrets - that this would be the same gun as offered on the above cruiser. Which is interesting, because the Ansaldo schematics clearly indicate it is for Chile, and I am not familiar with any 203mm ships offered to Chile in this period.

It is also interesting to note that the shell here is somewhat lighter than the RM's preferred 203mm projectile, which was 125.3 kg.

That was my fault. I mistook the article with another 2023 article on Italia class ironclad.