Fields of Fire

It is also germane to consider that even if individually light, AA weapons do add weight, and above the CG, which always, but always affect the ship's stability.

It's never just the weapon, either.  it's the mount, the platform for the mount, the ready service ammo (which adds weight and makes the platform bigger).  then you need a loader, and a pointer, and it keeps adding up.

And, it cannot block another weapon of any caliber.  It also needs to be out of the blast effect of the larger naval rifles aboard, too.

Then, the weapon availability per installed weight matters.  A 7.7mm machine gun round  barely reaches to the "pull out" altitude of dive bombers, and is mere impotent tracer fire for horizontal bombers or torpedo planes.  Going to a 20 or 25mm cannon will give a 2000yd sort of engagement range, about release range for torpedoes, but right at the maximum effective range for the rounds.  and that 25mm mount can add a ton of weight up  too high above the metacenter for every one installed.  So, you need a bigger gun. but they weigh even more.

The answer for fewer guns is to put them under director control, so that more guns are on one target at a time--this was the true secret of success for USN 40mm mounts.  And even then, that not-quire 2", 2# shell did not always have a lot of effect versus a 3-5 ton aircraft closing at 2-300kts.

USN perfected the "anti kamikaze" AAA mount in the Mk 22 dual 3"/50 cal, with radar aiming and radar proximity fuzing.  Just did so in early 1946.

The first point about this is what fitting the Mushashi kit is molded in. As the war progressed her AAA battery was increased.

The next point is that IJN shipboard AAA, from what I have read, was not as effective as USN. No radar guidance, no proximity fusing. They had no equivilant to the quad 40mm which could throw out a heavier shell a farther distance than their 25mm guns did. The US 1.1" gun had a similar performance and was replaced early in the war by 40mm's. The 5" Dual Puropse gun also was superior to its Japanese counterpart. When coupled with radar guidance and radar proximity fusing it really outclassed its' opposote number.

Musashi and Yamato were commisoned early on in the Pacific War, but did not see actual combat until mid to late 1944 at the Phillipine Sea and Leyte Gulf. It is interesting to ponder what effect they may have had on the Guadalcanal campaign had one or both been committed when both sides carriers were out of action and US land based airpower not as formidiable as what they would later face.

Glue Mark

Hey Everyone!

I was looking over this Musashi kit I recently bought, as well as researching old photos, and one thing I noticed was the relative dearth of smaller caliber AA guns sparsly placed over her decks, about 24 if I counted correctly. If I look at a North Carolina class, or an Iowa class, it seems that everywhere there is room, there is another 50 cal gun. The total for BB-55 was 48, an increase by a factor of two, and defending a ship 110 feet shorter.

Could this have led to inadequate overlapping of fields of fire, allowing better penetration of Allied aircraft through the ships' defenses, and been a significant factor in the Allies' ability to sink both Yamato and Musashi so quickly after their deployment?

Thanks,

Rusty

US BB's also had 3 inch, 4 inch, 5 inch and 9 inch guns as opposed to Oerlikons and Bofors.

Your average fleet replenishment ship had a 3" and a 5" open mount gun, which even well served had a slow rate of fire and little or no success against aircraft.

I would not say the japanese were better or worse than the USN in AA, although we prevailed, but the availability of the Swedish guns was a major factor.

Despite thier early success using aircraft against ships, the Japanese were slow to recognize and adopt strong anti-aircraft defenses. The Battle of Midway rudely awoke them to this error, but even after that incident they never put the same kind of effort into AA or CAP management as the US or Royal Navy, so yes it probably played a part in the loss of those ships.