6-inch semi-auto gun superior to 8-inch gun for cruisers?

How did the British 6 inch and 8 inch guns and mounts compare? The 6 inch armed Cruisers gave a good account of themselves in several surface engagements e.g. Battle of the Barents Sea.

 

I'd comment Sheldrake, but tough I've read a good bit on British battleships and carriers, not as much on the British cruisers. Hopefully, the experts will stop back by the thread and answer the question.

 

I wouldn't call myself an expert, but the British were one of the navies which tried to make their cruiser main batteries capable of antiaircraft fire. The 8" had 70 degrees elevation which complicated the design for little benefit; rate of train and rate of fire were inadequate for AA work, and the 8" had no AA (or HA as the British would say) gunnery control. The 6" elevated to 60 degrees, and I haven't read as much negative about them, but nothing positive in the HA/DP role either.

The RN also shared the belief that 8" gun cruisers were better for independent operations which might involve long-range daylight engagements while 6" were better for work with the battle fleet or destroyer flotillas; also for night action of course. This meant that 8" ships spent a lot of time in distant waters looking for raiders and such and didn't see much of the intense combat the smaller ships did; 8" cruisers were rarely seen in the Med for example.

I'm not aware of much difference between British guns and other navies', except that the USN's super heavy shells, introduced shortly before the war, gave our guns an advantage. Also as noted earlier here the US 6" had a bit higher rate of fire than other fleets'.

 

There were serious arguments that a 6" gun cruiser (12 6" guns in triple turrets) could overwhelm a 8" gun cruiser by sheer volume of fire. Consider 2 salvos were 2400 pounds of shells compared to 1,000 (250 each from tube of an 8" 8 gun heavy cruiser).

 

^
I'm guessing at night-time close range, yes. But a day-time running fight at long range? Probably not.

 

One peculiar consequence of the treaty system was that the large "light" cruisers were better armored than many 8" ships.

 

Yep. A 1945 cruiser was much better armored than most treaty cruiser predecessors.

There was also discussion on reverting to smaller battleships (20k tons) but no navy was willing go accept a WW I size dreadnought. Read that in Siegfried Breyer's book on Battleships & Battlecruisers.

 

There was no real discussion on 20k ton battleships...12-inch gunned 25k ton battleships, yes, but not 20k ones.

The British pressed for 25k battleships, because it best suited there interests. The industrial might of the upstart US would be negated, and the British would keep their 16-inch gunned Nelsons, and 15-inch gunned Hood, while all new construction would be limited to 12-inch guns. The US, of course, balked at this proposal, not only for the reasons mentioned, but, while Britain's Navy was what the US sought parity with, the US also saw Japan as the real threat, and 12-inch 25k ton battleships would be hindered in any war with Japan. The USN also saw the British network of overseas bases as the great equalizer in any fight. British overseas bases could keep their fleet supplied, while the USN had no such network of bases.

That is not to say the US did not work on such plans for short/small battleships...They did, but the designs were very cramped and had little in the way of secondary armament. Although, the US tinkered with the designs well into the 30s, there was little serious consideration given to actually constructing such short battleships.

 

Someone in the disarmament era went so far as to suggest that no warship needed to be larger than about 7000 tons, able to outclass any armed merchant ship. The only need for larger warships was that other navies might build larger warships.