Dive bomber accuracy in perspective.

WAFU said:

Yes, ships sent by Admiral Cunnigham to carry out an evacuation of the Army in the full knowledge they were likely to be sunk.
When told he could decline, he tersely replied

'It takes the Navy three years to build a new ship … it will take 300 years to build a new tradition'.

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I've mentioned that bon mot on this forum before, and quite plainly it's one of the best military replies I've ever seen to any order. This is a man who knew why he was there.

UK needs to name a capital ship after this admiral; he had the sinews of their finest men.

Zipper730 said:

The CEP figures are usually based on putting 50% of the bombs within a given radius, so the Ju-87 figures don't really give much for CEP computation.

Regardless the Ju-88 had a CEP of 50m or 164'0.5"

No idea about the Skyraider or A-10

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CEP assumes a Rayleigh (2 dimensional circular) probability distribution, so if you're putting 25% within 30 meters, you should expect to put 50% within 1.552 * 30 = 46.6 meters.

buffnut453 said:

Really? Maybe you should check with the men who flew these:

View attachment 706152

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The point was about what the Royal Navy went into the war with. New fire control systems, and reliable high-angle gun mounts, took years to develop in some cases.

Only one of the five aircraft you showed existed pre-war (as a torpedo aircraft), and the Vickers Vildebeest was horribly obsolete compared to the Fairey Swordfish.

(A point in your favor is that there were only ever 4 squadrons of Vildebeest, and 2 were in Singapore. The RAF probably considered the a supplement to the Royal Navy's surface and air power, rather than the main line of defense.)

elbmc1969 said:

The point was about what the Royal Navy went into the war with. New fire control systems, and reliable high-angle gun mounts, took years to develop in some cases.

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Quite right.

The L & M classes were laid down in 1938-40 and while their hearts were in the right place (or they were giving lip service to AA) the execution left a little something to be desired.

The guns would elevate to 50 degrees instead of the earlier 40 degrees (still not enough) but aside from the enclosed turret everything else was biased to surface fire and not AA. The heavier projectiles and casings slowed the rate of fire just a bit and when trained sideways the rate of fire fell off a bit more. The ammunition hoist came up through the center of the mount and did not rotated so while the hoists and guns were aligned with the guns fore and aft they were off by about 90 degrees when firing abeam.
I believe the ship pictured has a 4in gun in place of the aft torpedo tubes. It does have the quad 2pdr aft of the funnel.
Later destroyers got 55 degree elevation but aside from the Savage with her single experimental twin mount no British destroyer with heavier than 4in guns had elevation higher than 55 degrees until Sept 1944 with the Battle class.

Destroyers are very tight, difficult to design ships and high angle guns are heavier than low angle guns (mountings) and if you want AA main guns you need to leave something else out or design bigger ships which means you don't get as many. There often wasn't enough space/capacity to put in much for small AA guns, you need more crew which means more space for crew, more food, more water (or bigger water maker) and the ever present problem of top weight.
After the "M"s and the "N"s (repeat 'K"s) the British went back to 4 main guns instead of the 6 guns of the J & Ks in order to fit in the new "equipment" like more depth charges, a few light AA guns, radar, better directors and more crew. These later Destroyers were 300 tons (roughly) heavier standard weight than the old G,H and I classes despite have about the same nominal armament.
The L & M were about the same size as a Tribal. Swapped a set of of torpedo tubes for the extra twin 4.7in mount basically.

Did British destroyers use their torpedoes much in action during WW2?

Wild_Bill_Kelso said:

Did British destroyers use their torpedoes much in action during WW2?

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Very much so. From the Norway Campaign when HMS Glowworm single handedly attacked the German cruiser Hipper on 8 April 1940 before ramming her (her CO was awarded the VC for that action) through to the very last destroyer torpedo attack of WW2 carried out on 16 May 1945 when the 26th Destroyer Flotilla sank the Japanese cruiser Haguro in the Malacca Strait.

In between we have, for example, the First & Second Battles of Narvik, the Bismarck chase (when she was harried by destroyers during her final night), Battle of the Barents Sea at the end of 1942 (where the destroyers kept the torpedos in the tubes because the threat of torpedo attack was enough to drive the Germans off repeatedly), the sinking of the Scharnhorst at the end of 1943, various actions against Italian convoys and the Italian fleet in the Med 1941-43, various destroyer actions in the English Channel and Bay of Biscay in 1943/44, Sabang during Operation Crimson in the Indian Ocean in 1944.

Shortround6 said:

After the "M"s and the "N"s (repeat 'K"s) the British went back to 4 main guns instead of the 6 guns of the J & Ks in order to fit in the new "equipment" like more depth charges, a few light AA guns, radar, better directors and more crew. These later Destroyers were 300 tons (roughly) heavier standard weight than the old G,H and I classes despite have about the same nominal armament.

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Not true. A recurring theme in British destroyer development during the late 1930s and WW2 is the problem of ever increasing destroyer size and along with it cost of building such ever increasingly complex ships.

Things came to a head from late 1938 when the 1939 Programme was under consideration. Initial plans were for a repeat L class (the M class) and another flotilla of even larger vessels. But some in the Admiralty were seeking a smaller ship, somewhere between a I & J class. Unfortunately, the Mk.XX mount of the L class was being delayed and then the Treasury stepped in, and limited funding so the second flotilla that year were ordered as a repeat of the J/K class becoming the N class in order to get them sooner.

But with war looming numbers of destroyers became important leading to the design of a War Emergency Destroyer, initially considered to be an improved G class (itself 1,335 tons), with 4 single 4.7" mounts, machinery based on the J class (2 boilers instead of 3) and a quad pom pom from the J class and still just those 2 quad 0.5". These became the O & P (1,540 tons) classes ordered in Sept/Oct 1939. Along the way various main armament options were considered including two twin 4.7" from the J class and a new HA single 4.7" firing the heavier 62lb shell but it never materialised. The fall back was the single 4.7" that was tried & tested, uncomplicated and could be produced rapidly in large numbers.

The addition of extra depth charges, radar and more light AA came during their construction just as in the L/M/N classes and not as part of their design. While under construction it was decided to arm the ships that became the P class with 5x4" HA singles and equip 4 O class as minelayers with 4x4" HA singles.

Further War Emergency ships were required but with more range. This design started life as an improved J class hull with a transom stern, and with extra endurance courtesy of only needing half the magazine space forward due to there being single 4.7" instead of twins. It formed the basis of the 96 ships of the 3rd to 14th Emergency Destroyer Flotillas (the Q-C classes) ordered between 1940 & 1942 and completed between July 1941 and April 1947. These saw incremental changes during the production run, including:-

1. S class - introduction of a Tribal bow for better seakeeping following wartime experience with the J/K classes.
2. S class - introduction of the 55 degree elevation 4.7" mounts
3 S class - moving the Pom Pom to a bandstand between the TT and replacing it with the twin 40mm Hazemeyer where available.
4. Savage served as the trials ship for the twin 4.5" turret intended for the Battles and the single 4.5" used in later Emergency destroyers.
5. Z class introduced the 4.5" calibre and the more sophisticated K towere director
6. Ch class introduced the Mk.VI director at the cost of a set of TT due to the weight involved
7. Lattice foremasts were introduced from late1943 to carry the new radar sets higher to increase its range

Light AA varied across the ships depending on what was available when completed or when upgrades took place.

The big Battles of 1942 were controversial ships seemingly carrying not enough gun armament for the size of the ship, especially aft. That led to the 4" starshell gun in the first 5 1942 Programme ships and then a single 4.5" in the 1943 ships. The 1944 Programme saw the even larger D class with 3 twin 4.5" which proved even more controversial. When the entered service they were described as "Daring Class Ships" and not "Destroyers".

Shortround6 said:

Kind of the point.
The problem was not quite as universal as you think, at least in perspective or fleet thinking.
The US had lots of bristling flak ships in 1939 and many more on the way.
It turns out that what they thought would work didn't, at least until 1943.
The US Farragut class.
View attachment 705996
Of 1934-45 was just about as naked as any other Destroyer of the 1930s ( exceptions later) when it came to light AA. Four water cooled .50 cal guns were hardly sufficient even in 1935. However the big difference between the US Destroyers of the time (forget the 4 stackers) was that their 5in guns were dual purpose and true dual purpose, not dual purpose in name only. The Guns would elevate to 85 degrees, there were fuse setters on the mounts, there was a dual purpose gun director on top of the bridge. These mounts were not as good as the later mounts but compared to the British 4.7in guns of the time?????
At least the US destroyers could fire something into the air more the .50 cal guns.
The Germans never put DP guns on their destroyers.
If the French did it was only the very last ships built if any of them were completed as designed.
Italian destroyers never got true dual purpose guns, they could elevate to 40-45 degrees but they fired slowly (about 1/2 as fast as the Farraguts and they were slow compared to late US destroyers).

The Japanese were the only other navy to actual fit DP guns to their destroyers. That is guns that could elevate over 45 degrees. We can argue over rates of fire and rates of train and elevation but if your main destroyer guns won't elevate past 45 degrees and you have no real provision for AA fire control (high angle director, not low angle director making guesses)
then you are pretty much depending on maneuver and an handful (and a small hand full at that) of 12.7-13.2mm machine guns.

I would also note that the US had a tiny sliver of an advantage with the AA machine guns in that the .50 was water cooled and belt fed. The French, Italian and Japanese 13.2mm machine guns were air cooled and fed from 30 round magazines.
The US was also waiting for the 1.1 in gun to make it's long awaited appearance

The Germans may have had the best light AA. They had their 37mm semi-automatic guns and they had the old 20mm AA guns that fired under 300rpm.

British pulled a set of torpedo tubes off their ships and mounted an old 3in or 4in gun without any director to at least fire something upward. A few major shell bursts helped the crew think they were at least fighting back.

The US had deliberately sacrificed anti-ship capability with the 5in/38 for AA capability. Of course the long range anti-ship capability that other Navies were obsessed with was largely an illusion. Destroyers (especially before radar) didn't have the ability to spot the fall of shot, good enough range finders or steady enough platforms (less rock and pitch) to effectively fire at long range.
The French and German big destroyers with their 5.5 and 5.9 in guns were really backed into a corner when it came to AA.

So yes, there was a slow trickle of light AA guns sprinkled lightly over the ships of many fleets for several years. But the AA situation of even early/mid 1942 was not the situation of 1940.

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The main armament of British destroyers was to be used to protect the major warships against high level bombers.
From "Nelson to Vanguard" by D K Brown: "The 1931 Committee made some specific recommendations which had a considerable effect on destroyer design. In particular, they said that '...destroyers can assist in the defense of the fleet in the same way but, since they are not likely to be the object of high level bombing or torpedo attack. Their long range guns need not have great elevation.'" The argument was that destroyers would not be firing on planes attacking themselves but against planes passing by on the way to attack capital ships."
Slant fire capability was enough for that role. As it turned-out high-level bombers were not a threat to anything. However, dive bombers were not considered at that time as D K Bown notes in the same passage: "Similarly the 1931 Committe was a little early and only two years later would have recognized the threat posed by the dive bomber and the weakness of the fleets AA defenses against it (practicality apparent in the Didos and 'Hunts"). It is one of those not-uncommon cases in which a number of decisions, individually correct or, at least justifiable, add up to an incorrect solution overall. Or rather, where the solution decided upon proves to be the answer to the wrong question. Air attacks of the kind postulated by the RAF in 1931 were, in the event, countered quite well by the AA systems of the RN. These systems, however, were of little utility against the Luftwaffe's dive bombers."

Reluctant Poster said:

The main armament of British destroyers was to be used to protect the major warships against high level bombers.
From "Nelson to Vanguard" by D K Brown: "The 1931 Committee made some specific recommendations which had a considerable effect on destroyer design. In particular, they said that '...destroyers can assist in the defense of the fleet in the same way but, since they are not likely to be the object of high level bombing or torpedo attack. Their long range guns need not have great elevation.'" The argument was that destroyers would not be firing on planes attacking themselves but against planes passing by on the way to attack capital ships."
Slant fire capability was enough for that role. As it turned-out high-level bombers were not a threat to anything. However, dive bombers were not considered at that time as D K Bown notes in the same passage: "Similarly the 1931 Committe was a little early and only two years later would have recognized the threat posed by the dive bomber and the weakness of the fleets AA defenses against it (practicality apparent in the Didos and 'Hunts"). It is one of those not-uncommon cases in which a number of decisions, individually correct or, at least justifiable, add up to an incorrect solution overall. Or rather, where the solution decided upon proves to be the answer to the wrong question. Air attacks of the kind postulated by the RAF in 1931 were, in the event, countered quite well by the AA systems of the RN. These systems, however, were of little utility against the Luftwaffe's dive bombers."

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Hi
The USN also had some problems in their destroyers as not all of them had high angle 5 inch guns, as in the Porter Class (launched 1935-36):

Its main LAA were the two quadruple 1.1 inch (plus two 0.5 inch), which had their own problems:

Info from Friedman's 'Naval Anti-Aircraft Guns & Gunnery'.

Mike

Like I said before, in the early to mid-war (say 1938 or 39 through 1942) warships in general seemed to lack adequate air defense, with the US Navy perhaps a bit ahead of most others. This was alleviated at first by ad-hoc improvements done on an emergency basis, and later to a greater or lesser degree, formal refits, and the arrival of new designs with radar, more effective general purpose guns, more light flak guns and heavy machine guns, and so on.

But the simpler pre-war naval warships that actually did the fighting in the early months and year or two, coincided with the early strike aircraft including the converted airliners, biplanes, strange obsolete transitional aircraft, not quite perfected newer experimental types, and a few limited but capable pre-war types that proved amenable to at least some enhancements... many of which as we know proved to be fairly lethal regardless of their limitations. Case in point the tiny number of Fw 200s, the He 111, the SM. 79, the Swordfish, and yes indeed, the Stuka.

The D3A1, B5N and the SBD also proved to be quite capable of wreaking serious havoc, as did many of the land based Japanese bombers such as G3M and G4M. The Ju 88 also proved to be lethal in the Mediterranean for a while. Relatively slow aircraft like He 115, PBY, and Wellingtons also proved capable of sinking ships at night time.

When better AAA became available, longer ranged land based fighters arrived in Theater, and / or at least somewhat effective carrier fighters, naval or land based maritime strike aircraft needed to be faster and more capable as well. Thus ended the era of the slow dive bomber. Fast dive bombers never really arrived in time or didn't properly get debugged in time, though some were still used to effect regardless (SB2C). Fighter-bombers and converted land based light / medium bombers took up most of the rest of the slack.

IMO, the most important naval and especially ship to ship warfare took place up to about 1943, so any innovations (to either aircraft or ships) that arrived after that time had a bit less impact on the outcome of the war, though certainly they still mattered to the lives of the sailors and aircrew that used them.

I think there is a tendency in WW2 to always look at the latest and greatest designs ans being the only ones that mattered. But the truth is a lot of the fighting in WW2 was done by obsolescent designs or adapted designs that people had to make do with.

It had been mentioned that it was the F4F "that did the heavy lifting" holding the line until the hotter planes arrived.

To some extent that's definitely true, though I think the SBD was probably more important. F4F basically helped prevent catastrophe (in terms of US strike aircraft getting totally decimated or enemy strikes having too easy of a time of it) but they didn't really stop enemy strikes cold or totally protect USN Bombers.

Their impact on the war was less operational / strategic (i.e. winning specific battles) and more attritional, though arguably they did cause some serious harm to Japanese air strength in a fairly short period of 1942, specifically during the Solomon Islands campaigns. Not as much as the SBDs did sinking those carriers at Midway probably, but telling.

I would say that F4F would have helped a lot in some of those convoy battles the British had both in the Med and North Atlantic, but they never got enough of them in time. They had a few. F4F IMO is pretty lethal threat to He 111, Ju 87, SM.79 and can at least catch Ju 88s in most cases. I don't know the full combat history of the FAA Martlets but it seems like in the key convoy battles they either didn't have any or had just a handful.

Full disclosure: I have a soft spot in my head for the SBD.

I believe the F4F did indeed stop an attack cold against U.S.S. Lexington (possibly the second wave too).

SaparotRob said:

Full disclosure: I have a soft spot in my head for the SBD.

I believe the F4F did indeed stop an attack cold against U.S.S. Lexington (possibly the second wave too).

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Ok if that's true I stand corrected. I seem to remember from Neptune's Inferno and First Team they were usually only getting a few enemy planes at a time...

Wild_Bill_Kelso said:

To some extent that's definitely true, though I think the SBD was probably more important. F4F basically helped prevent catastrophe (in terms of US strike aircraft getting totally decimated or enemy strikes having too easy of a time of it) but they didn't really stop enemy strikes cold or totally protect USN Bombers.

Their impact on the war was less operational / strategic (i.e. winning specific battles) and more attritional, though arguably they did cause some serious harm to Japanese air strength in a fairly short period of 1942, specifically during the Solomon Islands campaigns. Not as much as the SBDs did sinking those carriers at Midway probably, but telling.

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The SBDs certainly wiped out the Kido Butai's aircraft and that's about, say four hundred aircraft or so? If my suspect memory is right, most of the aircrews were rescued. I think I read that in Shattered Sword.
The aircrews lost to the F4Fs over the sea or jungle were lost with their machines as well.

Wild_Bill_Kelso said:

Ok if that's true I stand corrected. I seem to remember from Neptune's Inferno and First Team they were usually only getting a few enemy planes at a time...

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The attack was by three(?) squadrons of unescorted G4Ms that were to do a level bombing attack. The torpedoes hadn't arrived at their base yet.

SaparotRob said:

The attack was by three(?) squadrons of unescorted G4Ms that were to do a level bombing attack. The torpedoes hadn't arrived at their base yet.

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Ah ok I do remember that. This is in part the basis of my notion that they would be deadly to say, He 111s.

There was also an account of an F4F literally beating a G4M out of the sky. The Grumman was out of ammo. The pilot lowered his landing gear and kept bouncing it off the Betty's wing. That might have been at the Battle of the Coral Sea, though.