Tribal class dd

[dunmunro]

The HACS versus Mk.37 controversy was done to death earlier this year on the Naweaps BvB forum. My opinion, for whatever anyone thinks it's worth, is as follows: the only party who took any real time to analyze and compare the two systems side by side on a technical hands-on basis was the Royal Navy. The clear conclusions of their technical experts can be read and inferred in the successive wartime editions of Progress in Naval Gunnery.

B

The RN was certainly influenced by the USN's overclaiming but I've never read of any real systematic study by the RN comparing the two. Certainly from our perspective, there appears to be little difference between the actual results achieved by the two systems.

[Francis Marliere]

Friedman says that the Mk37 was clearly superior to HACS but didn't shoot planes in large number either, untill the avent of good FC radars and proximity fuzes.
Anyway, the RN was much impressed by HMS Delhi when the cruiser was refitted during the war with 5"/38 + Mk37, and rated this combo as being superior to their own guns and FC.

[Byron Angel]

The RN was certainly influenced by the USN's overclaiming but I've never read of any real systematic study by the RN comparing the two. Certainly from our perspective, there appears to be little difference between the actual results achieved by the two systems.

..... It is not really necessary to plough through the "full-Monty" technical analyses. The PiNG commentaries summarize the conclusions. The short story is that the RN wanted to place a large production order for additional Mk 37 systems, but were frustrated in doing so by US refusal/inability to provide same due to the demands of their own naval construction program. The fairest thing to do IMHO is to read and digest what the PiNGs had to say.

Strictly my opinion.

B

[pgollin]

Friedman says that the Mk37 was clearly superior to HACS ........

Does he ?

[dunmunro]

The RN was certainly influenced by the USN's overclaiming but I've never read of any real systematic study by the RN comparing the two. Certainly from our perspective, there appears to be little difference between the actual results achieved by the two systems.

..... It is not really necessary to plough through the "full-Monty" technical analyses. The PiNG commentaries summarize the conclusions. The short story is that the RN wanted to place a large production order for additional Mk 37 systems, but were frustrated in doing so by US refusal/inability to provide same due to the demands of their own naval construction program. The fairest thing to do IMHO is to read and digest what the PiNGs had to say.

Strictly my opinion.

B

The RN wanted large numbers of guns and FC systems, but they could not order RN pattern systems in the USA, according to US Regulation, unless said system was also adopted by a US armed service. This forced the RN to order Mk 37+5in/38 systems if they wanted supply from the USA. The RN could have ordered USN pattern weapons to built in Canada, but they didn't and Canada produced FKC and RN pattern weapons.

[Dave Saxton]

untill the avent of good FC radars .

What were these good flak control radars? Mk35 radar didn't reach the fleet until the 1950s, and then it required a better director than the Mk38.

[Francis Marliere]

Dave, Phil,

I don't have the book at hand - and can't get it for some time. As far as I understand him, Friedman wrote that Mk 37 was superior to the numerous variants of HACS, but "did not shoot down many planes either". Dave, sorry, I did not note the detail of flak radars, I was mostly interested in the analysis of the first years of the war.

[pgollin]

.

One of the things I really wanted from Friedman's book was what was promised in the initial pre-publication blurbs - a proper analysis of the performance of the various systems against one another.

Unfortunately something went wrong and the book does not contain anything like that.

Instead, what you will find is the standard RN castigating itself over wanting something better (standard British service attitude), whilst the USN puts out lots of "positive vibes" (standard US service attitude) based on rather contradictory information. What makes this a little worse is that Friedman follows the standard US practice of burying the criticism in the footnotes - for instance South Dakota's ridiculous claim is not dissected in the main text, whereas if it had been an RN over-claim of such proportions it would have been.

.

[dunmunro]

Yes, and Friedman falls back on the using the USN's own kill stats to evaluate Mk 37's performance, when much more accurate stats are available, via Lundstrom, whose books are probably sitting in his library.

[Steve Crandell]

It's interesting how the USN detractors like to quote the very critical USN AARs when that suits their purpose, and then claim over exuberant kill claims when that does.

[Dave Saxton]

Dave, Phil,

I don't have the book at hand - and can't get it for some time. As far as I understand him, Friedman wrote that Mk 37 was superior to the numerous variants of HACS, but "did not shoot down many planes either". Dave, sorry, I did not note the detail of flak radars, I was mostly interested in the analysis of the first years of the war.

The Mk38 was fitted with MK4 radars during 1942 almost throughout the whole fighting fleet. This was a version of Mk3 for flak because it could lobe switch on the vertical axis as well as the horizontal. It was more capable than the British Type 285M (used with HACS) because the British radar could not lobe switch on the vertical axis. This, of course, only mattered if the target could not be seen at all.

By late 1944 Mk4s were being converted to Mk12s at 33cm. Mk12 had an auto track capability only in range. It was used with the Mk22 height finding radar for enhanced height finding. By late 1945 some Mk38 systems were fitted with Mk25 radars.

Mk25 was kind of a small antenna (with a compact dish instead of polyrods) version of Mk8/13 with a vertical scan feature added. It was certainly an improvement over Mk12 for surface fire control, but it was still not an ideal AA radar.

Even though these sets were not ideal AA radar, the operations manual warns that the Mk38 director could not keep up with these radars when tracking fast flying aircraft. Hence the Mk38 was actually considered obsolete by the USN themselves circa 1944, so it is kind of ironic that the internet has transformed it into the gold standard of DP director systems.

All of these radars offered only a marginal improvement over 1942 radar capabilities. To get a significant performance improvement for AA, what was really needed was conical scan radar, such as SCR-584 or Euklid. It wasn't a simple matter of just installing conical scan radars aboard warships, however. There were difficult technical problems to be worked out. This is why I'm puzzled by the capabilities being improved by late war radars. He is correct that the Mk25 would have improved the Mk38s capabilities vs surface ship targets.

[dunmunro]

It's interesting how the USN detractors like to quote the very critical USN AARs when that suits their purpose, and then claim over exuberant kill claims when that does.

Here's a very revealing quote from Friedman in NAAGaG:

Rapid pre-war expansion brought its own problems. The navy found itself flooded with new personnel, who has not recieved extensive training in technical schools before encountering such increasingly sophisticated equipement as the Mk 37 FC system. Exercise scores fell even though targets did not change very much between 1939 and 1941. Again, fortunately for the US much of the nessesary training was completed by the time the war broke out - when even more new sailors arrived.(page 9)

my bolding.

So AA practice scores actually fell as Mk 37 actually began to be used against aerial targets...! This is a pretty amazing statement and it speaks volumes about Mk 37 since AA practice results were already pretty dismal:

...A study of the results of antiaircraft firings by the ships of the Fleet, from July 1, 1938 to June 30, 1940, gave little cause for cheer or hope for solution in this area. This study showed that in 307 firing runs by 1.1", 3", and 5" antiaircraft guns against high-altitude, horizontal-bombing drone aircraft, dive-bombing drone aircraft, and low-atitude, horizontal bombing drone aircraft, only 5% of the drone target aircraft had been hit seriously enough to stop the bombing attack and only 17% hit at all.(10) Increased numbers of guns on the ships of the Fleet, and putting increased skill into using them would undoubtedly improve results, but it did not appear this action would provide the protection sought..."

(10) "Defense of the Fleet Against Attack by Aircraft", General Board No. 420-11, serial 1952-A of 12 June 1940, GB Files, NHD, p. 1; CNO, serial 085323 of 12 June 1940, letter. " Commander Carrier Division One, Feb. 1940, letter to CINCUS.
Richardson, On the Treadmill to Pearl harbor, p224.

Friedman glosses this over with a comment about untrained personnel, (with no accompanying reference) but again the whole point of Mk 37, the Mk1 computer, and RPC was that it was supposed to be easier to use than non RPC equipment, with the director crew merely keeping their sights on the target while the computer did the rest. Apparently this was not so...and if the USN, with a access to relatively large pool of well educated men struggled with Mk 37, how well could the RN expect to do with the same equipment? However, the main point is that Mk 37 did not do well in pre-war AA practice and we also know that it didn't do very well at all in 1942 in actual combat (my educated guesstimate is that Mk 33/37 controlled 5in guns shot down about 5-6 IJN aircraft in the Pacific in 1942.), so claims for it's superiority over HACS or FKC must be taken with a very large grain of salt, as pre-war trials and actual combat just didn't show any measurable superiority.

[Steve Crandell]

Well, you've already indicated that it was pretty much impossible for Mark 37 systems to even engage aircraft because it was too difficult to get it on the target, so why the concern about how well it did if it ever could actually engage one?

[Francis Marliere]

One of the things I really wanted from Friedman's book was what was promised in the initial pre-publication blurbs - a proper analysis of the performance of the various systems against one another.

Unfortunately something went wrong and the book does not contain anything like that.

I agree : I was too, a bit upset by the book. I fear however that there is nothin better. I feel, on the other hand, that the book on AA guns is better than the previous one on surface gunnery which IMHO focused too much on how systems worked and not enough on what they could achieve.

[Dave Saxton]

According to Barnett http://www.amazon.com/Engage-Enemy-More ... 0393029182 and quoting Roskill, and the DNO and others, HACS was an unmitigated diaster. Worst AA system of the era.