USS San Fransisco v Deutschland v Zara v Takao v Norfolk?

[parsifal]

I have no idea on the relative effecctiveness of the different shells....I wonder how much more efficient Germans ammunition in comparison to Allied ammunition was in bringing down aircraft. By "efficient" I mean how many rounds per kill were needed of the Mine shells to bring down an aircraft as compared to the allied 40mm rounds.

On land, the average number of rounds expended per kill by the Flak artillierie in 1942 was about 3500 to 4000 for each kill of a high level strategic bomber. By comparison, I recall reading a USN report somewhere that talked about 1500 rounds against low flying Japanese aircraft. This figure had apparently dropped to about 500 RPK by late '44. But the German and allied RPKs are simply not comparable....the data would need to be against like targets with like weapons. Still if there is any information out there, it would be useful to know.

 

[timshatz]

I have no idea on the relative effecctiveness of the different shells....I wonder how much more efficient Germans ammunition in comparison to Allied ammunition was in bringing down aircraft. By "efficient" I mean how many rounds per kill were needed of the Mine shells to bring down an aircraft as compared to the allied 40mm rounds.

On land, the average number of rounds expended per kill by the Flak artillierie in 1942 was about 3500 to 4000 for each kill of a high level strategic bomber. By comparison, I recall reading a USN report somewhere that talked about 1500 rounds against low flying Japanese aircraft. This figure had apparently dropped to about 500 RPK by late '44. But the German and allied RPKs are simply not comparable....the data would need to be against like targets with like weapons. Still if there is any information out there, it would be useful to know.

Might also have something to do with ships having compacted AAA and firing at a target with a 0 (or close to 0) defection while a land battery of AAA would normally be shooting deflection shots anywhere up to 90 degrees. Of course this only applies to a single ship. In a formation, it would be different for the other ships not being attacked.

Also, aircraft were closing on the ships while the land batteries were rarely the target and usually got a 90 (or some variation of) deflection shot at distances up to 30K feet. Makes land shooting more problematic.

Lastly, Germany did not have the Prox fuse whereas the US Navy had it for anything over 40mm.

Just some food for thought. Additional info.

 

[renrich]

The Alaska class may have been called large cruisers but, in reality, they were BCs, built in reply to Scharnhorst class. They were useful only because of high speed and heavy AA armament. The US's first treaty cruisers, Pensacola class, were designed and built with torpedo tubes, which were later removed. I believe the theory on that was that the 8 inch guns and high speed of the cruisers negated any capability of torpedoes. Later in the war with the efficient use of radar controlled gunfire, that may have been true. Originally, the Pensacolas were not called heavy cruisers but were labeled as scout cruisers. As far as triple A on US cruisers is concerned, the prewar ships rapidly gained more and more AAA capability along with the equipment and personnel to operate them which made them top heavy and overcrowded. One of my uncles was a CGM(chief gunner's mate) on Salt Lake City(CA25) from 1941-43. In 1943, (I think) they were in Pearl Harbor for an overhaul. The ship carried 4 scout planes and they prevailed upon the shipyard to install two twin mount 40 mms amidships, just aft of the catapults and offloaded two of the scout planes. All of this without official permission from Buships.