If you look at the capital ships towards the end of WWII, every flat surface seems to have sprouted an AA weapon of some sort -- from .30 cal machine guns to 20mm and 40mm cannons to 5" guns.  

How was the fire of all these weapons coordinated? Did every gun commander just choose a target or was there some coordination from a central command structure?

Asked my grandfather this once a loonngg time ago,he simply said everybody was gunning at any thing that came in.

Other than maintaining a formation around the carriers, along with a picket force of DD or DEs (partially to draw off aircraft from the main force), the individual ships did not coordinate their AA fire among themselves.  Whatever came within their range and sight was the target.

Ships developed CiC (combat information centers) during the war to help direct aircraft to intercept.  Some radars (which fed into CiCs) also helped coordinate a ship's AA fire.

My understanding is that the guns had directors.  I know the 5inch and 40mm guns had directors.  I've seen pictures of them.  The 5in used the radar directors on the port and starboard side I believe.  The 40mm used manual targeting and got their information from another director's tub.  They didn't use radar.  Not sure what the 20mm used if anything.

Directors(edit:radar type) in WWII weren't really good against fast flying aircraft. They were dandy against other ships.
ETA: I would imagine the 5 inchers had to be optically directed against aircraft.

The 40mm was manually sighted, as were the 20mms.

What really made the 5 in a player was VT frag.

Cool!  Thanks for the info.

The 5inch directors had optics as well as radar.  They were the same type of directors as the 14"-16" guns used.  Not sure about the electronics, but the housing and radar were the same type.  The directors might very well have used the optics to direct the 5" in high angle (antiaircraft) fire.

Quoted: The 5inch directors had optics as well as radar.  They were the same type of directors as the 14"-16" guns used.  Not sure about the electronics, but the housing and radar were the same type.  The directors might very well have used the optics to direct the 5" in high angle (antiaircraft) fire.

That's why I edited my post to be more specific.

I think you'd be surprised about how much elevation is really needed; it's not that much really. Although, I'm pretty sure they were able to do high angle. I remember reading about the Yamato using its 18" guns for AA fire. I would imagine if the Japanese could use their 18" guns, we could use the 5" guns. Then the question becomes what was the slew rate.

Quoted: That's why I edited my post to be more specific. I think you'd be surprised about how much elevation is really needed; it's not that much really. Although, I'm pretty sure they were able to do high angle. I remember reading about the Yamato using its 18" guns for AA fire. I would imagine if the Japanese could use their 18" guns, we could use the 5" guns. Then the question becomes what was the slew rate.

Didn't the Yamato use the 18" guns to throw geysers of water up into the air like the Bismarck did agains the Brits or did they actually fire at the US aircraft?  If they could fuse the projo's with time or VT fuses, it should work if they could get the elevation on the guns.

Quoted: Quoted: That's why I edited my post to be more specific. I think you'd be surprised about how much elevation is really needed; it's not that much really. Although, I'm pretty sure they were able to do high angle. I remember reading about the Yamato using its 18" guns for AA fire. I would imagine if the Japanese could use their 18" guns, we could use the 5" guns. Then the question becomes what was the slew rate. Didn't the Yamato use the 18" guns to throw geysers of water up into the air like the Bismarck did agains the Brits or did they actually fire at the US aircraft?  If they could fuse the projo's with time or VT fuses, it should work if they could get the elevation on the guns.

VT was a closely guarded secret in WWII; the Japanese didn't have it.

My understanding from what I have read is they attempted direct fire. It was basically ineffective.

Speaking of WWII shipboard anti-aircraft fire, I remember hearing about "pom-pom" guns as a kid. Is anyone familar with the term and what it applies to?

Quoted: Speaking of WWII shipboard anti-aircraft fire, I remember hearing about "pom-pom" guns as a kid. Is anyone familar with the term and what it applies to?

I'd speculate that its the sound of the twin 40's

Quoted: Speaking of WWII shipboard anti-aircraft fire, I remember hearing about "pom-pom" guns as a kid. Is anyone familar with the term and what it applies to?

Twin or quad 40mm Bofors cannons.  This was a British term first I believe.

Quoted: Didn't the Yamato use the 18" guns to throw geysers of water up into the air like the Bismarck did agains the Brits or did they actually fire at the US aircraft?  If they could fuse the projo's with time or VT fuses, it should work if they could get the elevation on the guns.

Read a book about the Yamato(from the Japanese viewpoint)couple months ago and it said the Yamato had a type of shotgun round for the 18 inchers for AA defense.

Quoted: Read a book about the Yamato(from the Japanese viewpoint)couple months ago and it said the Yamato had a type of shotgun round for the 18 inchers for AA defense.

Hmm, tell us more...

Quoted: Speaking of WWII shipboard anti-aircraft fire, I remember hearing about "pom-pom" guns as a kid. Is anyone familar with the term and what it applies to?

In the beginning of the war, the US also was using a quad 1.1" AA gun, but the 40mm Bofors and
20mm Oerlikons replaced them due to reliability and range issues. This might be the originator of
that nickname.

Quoted: Read a book about the Yamato(from the Japanese viewpoint)couple months ago and it said the Yamato had a type of shotgun round for the 18 inchers for AA defense.

Giant beehive round using flechette type projectiles. Supposedly used in the battle where Yamato
went down. Rounds were reported to have been ineffectual.

I've also read somewhere that the Japanese gunners hated using the 18" AA rounds because they caused severe bore erosion problems and that just firing a handful of them would ruin a bore.

Quoted: Quoted: Read a book about the Yamato(from the Japanese viewpoint)couple months ago and it said the Yamato had a type of shotgun round for the 18 inchers for AA defense. Giant beehive round using flechette type projectiles. Supposedly used in the battle where Yamato went down. Rounds were reported to have been ineffectual.

I have several books dealing with that.
This is from memory, so it might not be totaly accurate, but what came out of the shell were burning rubber balls.
They were supposed to stick to planes.
I will check tomorrow and confirm it.

that is indeed true.  however the rounds were not developed for anti-aircraft use.  the type-3 shells were designed to be fired at airfields in order to destroy anything that was sitting on the ground.  there was an issue with this when the tokyo express was going to visit henderson field one night and ran into allied naval forces and the japanese battleships fired a bunch of shrapnel at the american ships.  

also iirc the reason the aa fire was ineffective against usn aircraft the day the yamato was sunk was because she was essentially firing blind.  she was shooting based on radar and the ranges were incorrect.  

Alright, I found the reference books that I was looking for.
The beehive round (Type 3 normal round) was for the 46 inch cm main gun that was able to elevate to 45 degrees..
It had a fuse on a timer and released about 1000 burning rubber balls, then the canister exploded and added shrapnel to the mixture.

This round first saw during the October 1944 Battle of Leyte Gulf.
Due to the “shot gun” effect engulfing the whole formation of airplanes, the American changed their tactics to attacking from all sides.

My sources say that the type 3 round was developed for anti-aircraft use, could you tell me your source?
Mine are “The compass“ from Koudannshiya, and ”The history of the Yamato” from Kadokawa.
The titles are both Japanese so I translated them.

Edited to remove stupid mistake.

There was a special on PBS last night about the sinking of the Yamato.  They showed pictures of the bow and other pieces of the ship on the bottom.  It is lying 1200 feet below the surface, blown in two.  The ship capsized when it went down and the three main turrets fell off the ship and are lying upside down on the sea floor.  The mid and rear section of the hull are upside down as well.  The drawing they showed looked like there were two holes in the bottom of the hull from magazine explosions as well.  Pretty good show, all in all.  Here's a link to the website.

Sinking the Supership

"46 inch main gun" huh?

i can not unfortunately remember the source of my info.  i believe it was from some articles and reports and such on naval activity around guadalcanal.  some of the articles were in World War Two magazine.

My father in law was a 20mm gunner on the USS Gridley in WWII and this is what he had to say....

On the 20mm you had 1 gunner and 1 loader.The ammo was in something akin to a beta C mag the way he described it.There was no real spotter.They would take turns-1 day you're the gunner,next day you're the loader.Interestingly my F in Law said the guys on the 20mm, it was not their regular job.He was actually a firefighter.


The 40mm was very different-this was their regular job.That's all they did.He said you had 1 guy to traverse left/right and 1 guy to traverse up/down.These were twin barrels so you had a loader for each barrel and then each loader had a guy feeding him the ammo clips from the ammo locker.You also had a gunners mate with a headset on and he talked to the radar room thus he would give you a heads up on where they were coming from.

Quoted: "46 inch main gun" huh? i can not unfortunately remember the source of my info.  i believe it was from some articles and reports and such on naval activity around guadalcanal.  some of the articles were in World War Two magazine.

It was an 18 inch gun on the Y-boat. IIRC that's about 46cm, maybe that's where the number is coming from?

Quoted:
"46 inch main gun" huh?

...snip...  quote]

Sorry, my mistake, it should have been 46 cm main gun.

20mm guns were undirected...the gunner just pointed and shot at anything that came into his range. Late in the war they started mounting a lead computing gunsight on them...

40mm guns were directed. Look at good photo's and you will see that for every 40mm tub there was usually a corresponding director tub. I believe of the top of my head they were Mk 41 directors. It was a simple optical device (same lead computing basic sight eventually fitted on the 20's) with handlebars and switches and connected to a computer (WWII type mechanical...).

The director would follow a plane, keeping it in a reticle, when he had it "caged" he would squeeze the handle on the grip. As long as it stayed "caged" the computer would calculate deflection angle, lead, etc, and feed it to the gun captain of the 40 it was connected to. Of course they could be aimed un directed too...

5" typically used the big directors, I forget the nomenclature off the top of my head. They were originally optical, but by mid war were radar directed...early on the distinctive "W" on its side shaped antenna, later a circular antenna. Look at good pics, especially on DD's...you can't miss them. Same deal, crew inside the director would choose a target, track it, data was computed and fed to the 5" turrets.

As far as fuzing, yes, we were the only ones to have the VT type fuze. It was a fuze that used magnetic fields to determine detonation. The fuze had a series of thin copper plates along with an ampule of nasty acid. When fired the ampule would break, and acid would flow along the plates, and it would create an electrical field I guess. When it neared a large metal object the change in fields would set off detonation. So when the shell passed within range of an aircraft...BOOM.

It was one of the things credited with winning the war. For example, Germans only had time fuzes for their main AA guns. While they had the best technology for timed fuzes...they still were nowhere near as good as VT's. It is thought that if the Germans had good VT fuzes, they could have made the bombing campaign costly enough to cause its cessation. Luckily they never developed a good mass production VT fuze....

Quoted: 40mm guns were directed. Look at good photo's and you will see that for every 40mm tub there was usually a corresponding director tub. I believe of the top of my head they were Mk 41 directors. It was a simple optical device (same lead computing basic sight eventually fitted on the 20's) with handlebars and switches and connected to a computer (WWII type mechanical...).

I don't recall any directors on 40mms. Photos please.

The original question wasn't about firecontrol direction, it was about coordination. Big difference.

Quoted: Quoted: 40mm guns were directed. Look at good photo's and you will see that for every 40mm tub there was usually a corresponding director tub. I believe of the top of my head they were Mk 41 directors. It was a simple optical device (same lead computing basic sight eventually fitted on the 20's) with handlebars and switches and connected to a computer (WWII type mechanical...). I don't recall any directors on 40mms. Photos please. The original question wasn't about firecontrol direction, it was about coordination. Big difference.

I don't know how to post pics here, but here is a link that is pretty good covering WWII FC...the 40mm directors were the Mk 51....

http://www.de220.com/Armament/Fire%20Directors/fire_directors.htm

That's weird. I did a search last night, edited my post, and linked to that website only to have it not post. Weird.

I remember seeing those directors now, but for the life of me I couldn't remember a director for the 40mm.