I know everyone hates "best of" threads but they do generate debate. So what's your choice for best heavy AA weapon on a WWII era ship. My vote goes to the US 5"/38 tied to the Mk 37 gun director and using proximity fused ammunition. Does any other weapons system come close for this application? Make your best case. 5"/38 single mount on a Fletcher class destroyer. 5"/38 twin mount on a US battleship. This is the mounting served by the ships Marine Detachment. Mk 37 director.
We should speak not only about the gun itself , but also about its shells and fire control systems. In these two aspects, I think, heavy AA armament of US ships was really the best during WW2. Regards,
The mount and shell handling equipment also allowed for a very impressive rate of fire for the 5"/38. If you look at the ballistics of the shell the Japanese 3.9" gun does have some advantages but the more factors you include the better the 5"38 looks.
How would the British QF 4.5inch mark stand up against the U.S.5inch A.A.gun?.I have no idea about radar/fire control,etc,simply no idea,cheers. I would like to see the comparisons of all the main ship-born A.A.Armament and the various above radar etc.Perhaps a list of guns from all the major and/or minor powers would help.Any help at all would be most welcome.
There is a cost to the Japanese gun's ballistics: Barrel life of the Japanese 10cm gun: 350-400 EFC Barrel life of the American 16in/45 gun: 395 EFC Barrel life of the American 5in/38 gun: 4600 EFC The 4.5in gun was the best British DP weapon. It fired a nice big shell, and while it didn't match the 5in/38's rate of fire, it was still respectable in that regard. It fired at a lower velocity but still out-ranged the 5in/38. Apparently it didn't fragment as well. I'm sure Navweaps has good info on all these guns.
I don't like the 5"/38, as a weapons system it was very good for it's time but as a gun there were better ones though not many, my vote goes to the british 4.5 with the 4" a close second. BTW I have a suspicuion the /38 length is measured the US way not the German one so it's not as short barrelled compared to it's contemporaries as it looks.
Again, the German gun has higher ballistics standards, but in practical terms, the 5in/38 is preferable, in my view. In various mounts, the 10.5cm could elevate at 12deg/sec and train at 10deg/sec, maximum; the slowest 5in/38 DP mount elevated at 15deg/sec and trained at 25deg/sec. The German triaxial mounting was admirably engineered, if not practically.
The German gun also seems to have a slower rate of fire. Does anyone know how accurate the publishded numbers are? I've read a number of accounts of the 5"/38 exceeding it's published rate of fire by a significant extent where other weapons often rarely if ever made it up to their full rate of fire in practice. I also seem to recall that due to the ammo handling installations the 5"/38 didn't get "starved" of ammo after the ready rounds were fired unlike some others. It doesn't sound like the German gun was fully enclosed either.
I was thinking more along the lines of best overall, but we can redefine however the members steer the discussion. One thing that the 5"/38 has going for it, that you might not have considered, is the fact that it is a dual purpose gun (DP). For example the US Navy also had the 5"/25 which was a standard AA mount and the 5"/54 5"/38-55lb projectile @ 2600 fps/ceiling 37,200 ft /max range 18,200 yds/ROF 12-15 rds per minute (pedestal mount)-15-22 rds per minute (base ring mount)/max elevation +85 degrees/@ 4,600 rd barrel life. 5"/25-54lb projectile @ 2155 fps/ceiling 27,400 ft/max range 14,500 yds/ROF 15-20 rds per minute/max elevation +85 degrees/@ 3000 rd barrel life. 5"/51-50lb projectile @ 3150 fps/ceiling N/A /max range 15,850/ROF 8-9 rds per minute/max elevation +20 degrees/@ 900 rd barrel life. Many ships carried a mixed secondary battery of 5"/51s for surface action and 3"/50s for AA defense. By using the 5"/38 you had nearly the performance of the 5/51 against surface targets and a much greater ROF, along with superior AA performance to the 3"/50 with comparable ROF. By eliminating the duplicity you had more tubes available for either employment.
Just for ease of discussion here is the metric conversion of the inch/millimeter for the guns so far mentioned. 5"=127mm 4.5"=114.3mm 4.1"=105mm/10.5cm 4"=101mm 3.9"=99mm
Inferior. The shell was rather heavy resulting a lower sustained rate of fire. And RoF is what it comes to. A guy in another forum makes the case that no HAA gun was very good at killing planes before the proximity fuse. The gun directors had trouble coming up with a firing sollution fast enough, especially if the planes flew evasive manouvers. Other candidates for best HAA gun are: -5"/25: same RoF and AA-ceiling as the 5"/38 but smaller and lighter -4"/45: even smaller and lighter than the 5"/25 The big advantage of the 5"/38 is that it´s also very good against surface targets, making her the best DP-gun. -Markus
Just to clarify, the 4.5in gun's shell is no heavier, but its ammo is fixed; the shell and cartridge make heavier work for the gun crew. And yet the 5in/25 also had fixed ammo, and that seemed to work fine. The velocity of the 25cal gun was really low, 2110fps, with a consequently limited reach. The ceiling was 27,000 ft, as opposed to 37,000 ft for the 38cal gun. By the way, the 38cal gun appeared after the 25cal and 51cal guns were standard weapons. What's the average of 25 and 51? I don't think anyone has mentioned the Japanese 5in/40. Its main drawback was the mount speed, very slow in some early mounts but later 16deg/sec in elevating and training. The Japanese 4.7in gun was also a reasonable weapon. The Italian 90mm gun as used aboard Littorio was, according to everything I've read, a magnificent piece of engineering. But again, the real world was not kind to it.
I stand corrected but does the lower AA-ceiling of the 5"/25 matter? Level bombers could not even hit a moving ship from under 10,000ft. They had to skip-bomb for that, didn´t they?
No, ceiling itself doesn't seem very important for a ship-based gun, does it? However, the factor that causes such a low ceiling--the gun's limited velocity--has more significant drawbacks. Targeting a fast-moving aircraft becomes harder, though the long life of the barrel (almost as long as in the 5in/38) implies regular performance (accuracy) over a long period of use. The main issue will be the gun's reach. Range is roughly proportional to ceiling, and the sooner you can engage the incoming attacker, the better that is for you.
The problem though is that the British fire control directors all well... blow. They are somewhere between adequite and mediocre in operation. In this respect they just can't seem to get things right during the war. The result can be seen in new variants of their gun directors coming out with virtually every new class of ship.
Here are some pages with info on the Japanese heavy AA guns: 5"/50 DP 5"/40 DP 4.7"/45 DP Some data but few comments. Limited usage though. 3.9"/65 DP As mentioned barrel wear was a big problem with this one. I think it was also dual purpose though. And a page with links to the above as well as heavier and lighter guns: Japanese Naval Ordnance
