You stated above:Steve Crandell wrote:
As far as I know, no-one mentioned the L-class except you. I was talking about the Tribal class, which is the topic. I mentioned replacing the 4.7"/45 with 4"/45 because the latter were better AA weapons, and you said you doubted the 4"/45 were better AA weapons than the 4.7"/50. As far as I can see, that is not relevant because 4.7"/50 guns were not installed on Tribal class destroyers.
With respect to the 4.7"/45 guns installed on the Tribals, they could traverse at only 10 degrees per second. If you are being attacked by aircraft, your ship is usually maneuvering radically. I don't know the turn rate of a Tribal, but I suspect it is high enough to make tracking aircraft problematic when you have a gun which traverses so slowly. This is particularly problematic when a weapon gets wooded due to a turn and has to re-engage on the other side, but just tracking an aircraft in a turn could also be a big problem. That is why DP guns normally were given a high traverse rate on the order of two times that of the 4.7"/45 or more.
As an aside, the USN's 5"/51 gun was not considered for AA use because it was too heavy and it's traverse and elevation rate was too slow. They went to a 5"25 cal gun for AA use, but in practice it was being used to engage surface targets where it's ballistics weren't really up to the task, and my understanding is that that is why the 5"/38 was introduced ... a compromise between the two conflicting requirements.
Finally, I can understand if you have credible information which conflicts with the navweaps site, but why exactly should I believe you over them in this case? As far as I know, they are capable of doing the same sort of research as you are.
"A couple of the later ships of the class had 8x4""
And I pointed out that the only war built destroyers to mount 8 x 4in were the 4 x L class.
The info on the Abdiel class comes from the Warship profile and it quotes some the design documents to illustrate that the original design armament was 2 x twin 4in/45, and it discusses the ensuing debate that saw them fitted with 6 x 4in.
The 4.7in twin was a powered mount. The early 4in twin (as fitted to the Tribals) was entirely hand powered.
No WW2 warship that was manoeuvring radically (including battleships) could maintain an AA FC solution.
Even land based systems based on SCR-584 could not track close range targets where the tracking rate exceeded about 5 degrees/sec or so.