KevinD wrote:
And Gregory, would love to take you up on further discussion re DR and Java's Bofors, but best we do that over on one of their respective threads.
posting.php?mode=quote&f=48&p=960185And so we can!
A few important notes before I post the rest of this. What I am about to post is based off of what I have intuited about the AA systems on the De Ruyter and Java from looking at pictures of them and from the blue prints of the ships. I do not speak Dutch, and I do not have access to hard documents which prove what I am saying to be true. Thus if you have information which shows that I am incorrect, I would be happy to see it! That being said from studying those pictures, I'm pretty sure this is correct. Again if you know something I don't about these guys, I am all ears!
Anyway, here we go! So my thought process on these guys started several years ago when I was thinking about the fact I have seen the designs of both of these ships get a lot of flak for the layout of their 40mm Bofors. As many have pointed out, one well placed bomb would decapitate their AA systems. However, I am of the opinion that naval engineers of the 1930s actually had a decent idea of what they were doing when it came to building ships, especially the Dutch designers. Therefore I do not accept the premise that they made a ship with this vulnerability simply by overlooking the obvious risk of placing the guns so close together; that is far too big of a mistake to miss unless there was something more going on with them than meets the eye.
I was thinking about what that could be when I looked at a picture of the Eendracht's original blue prints, and I noticed something rather interesting in her design. She has two clusters of AA guns, and inside of both of those clusters is that boxy looking range finder from the De Ruyter. It makes no sense that she would have a back up fire control director right in front of her main fire control director, as in every other naval design that goes somewhere aft if it exists at all. Then it hit me, I'm fairly certain that boxy fire control director on the De Ruyter is actually a fire control director for her 40 mm guns, not her main battery. It only shows up on Dutch blue prints amid the 40 mm Bofors guns. And I have only ever seen two which were actually made, one on the De Ruyter and a second one on Java. Critically, Java only got that boxy fire control director after she picked up her 40 mm Bofors to replace her 40 mm Vickers guns.
Therefore while I have never seen it directly stated in English (Though
https://netherlandsnavy.nl/ seems to heavily imply it) I'm pretty sure those 40 mm Bofors guns were very intentionally clustered around a centralized fire control director so that they would have a concentrated fire at one target under centralized controlled by the box director (circled in red in pictures below). This would essentially create a 40 mm mini (maxi?) gun of sorts which would probably have been absolutely devastating to any planes which were foolish to venture too close. And if it is true, I think it would be fair to say the Japanese are lucky that they stuck to high level bombing against the ABDA, as I don't think a torpedo attack against the Java or De Ruyter would have ended very well.
This would explain a few things about the De Ruyter and Java
1.) Those shields they got during the ABDA campaign which were unique to the two of them. Clearly those shields would have massively limited the lines of sight of the gunners, however that is not a problem if they guns are being controlled by a centralized fire control director. Also, I'm guessing the purpose of those shields was for surface combat particularly at night, as the Dutch seemed pretty keen on using them against opponents search lights in the Battle of the Badung Strait.
2.) It explains why De Ruyter's AA went off line during the Battle of the Makassar Strait. It doesn't make much sense to me that a near miss would prevent all her 40 mms from shooting. However, if they were under coordinated control and given how sensitive complex fire control systems like that were in the 30s and 40s it would make a lot of sense that a near miss could damage or knock off line the AA director, thus taking the De Ruyter's guns off line as a whole
3.) It also explains why the Tromp never got those shields, as her 40 mm Bofors were of a different type, and she was never fitted with that centralized director (if indeed that is what that box is) to save weight. Those shields certainly would have interrupted the view of gunners, which would have been much more problematic on a ship like the Tromp which did not have that centralized fire control system fitted
4.) Lastly and most of all, as mentioned above it explains why the Dutch were willing to risk having all the AA guns on their ships so close together. While they do seem to have put all their eggs in a basket, that basket would be pretty nasty for anything which flew too close.
I do apologize if this is something which is not new information, or if this is totally wrong, however usually all I read about the De Ruyter/Java is criticism for this AA gun layout, when in fact it seems to me like it is a risk which was deemed to be acceptable in order to have such a potent AA capacity. Please note, in the attached pictures, I circled what seems to be the AA fire control director in red, and the main batter fire control directors in blue.
One last thing which is just interesting to note: in that photo of Java in her camouflage, she does not seem to me to have her 40 mm shields yet (blue arrow). So either they were added after the war started or she was camouflaged before the war began. Anyway, I would be happy to hear y'all's thoughts on the matter!