Mushasi & Yamato special AA weapon

[Andy H]

viewtopic.php?p=458830#458830

In thwe above link it mentions that this weapon when used damaged the rifling of the main 18" arnament, which was shown through test firings.

My question relates to the sinking of both the Mushasi & Yamato. I know that it's use was requested by certain officers on the former but it's use was denied since the captain wanted to save his guns for the coming sea battle with US surface ships (which never occured).

Does anyone know if this weapon was used in combat and to what effect?

Andy H

[Juha Hujanen]

There's brief account in Bauer-The History of WW2.

Of Yamato's last battle:



The American pilots were impressed by the massive A.A.fire which came up at them.The Japanese had learned the lesson of air power well,and by the time of her last voyage Yamato bristled with no less than 146 25mm A.A.gunns.Most impressive of all,however,were the San-Shiki shells fired by her man armament,which may be best described as 18-inch shotgun shells.
Yamato's main battery was designed for use in the anti-aircraft role and the San-Shiki shells were crammed with incendiary bullets.
The idea was that the shells would be fired into a group of enemy aircraft;the shells would then burst like a shotgun fired into a flock of birds,mowing down the enemy planes.It was found,however,that the terryfying blast of Yamato's 18-inch gunns when fired at maximum elevation only served to disrupt the main volume of A.A.fire.The San-Shiki shells proved to be a failure,like so many other impressive-sounding Japanese ideas.

Cheers/Juha

[WalterS]

From "A Glorious Way to Die," by Russel Spur:

p.81

"The main after turret (of YAMATO) swung ponderously to port. The three big gun barrels lifted to maximum elevation. This did not give them much antiaircraft capability, but a new shell, the San-Shiki, nicknamed "the Beehive," supplemented the regular armor-piercing ammunition. The projectile was packed with layers of incendiary pellets, Watanabe was told, which exploded at set ranges like the blast of a shotgun. The only drawback, apparently, was that the copper drive bands of the "Beehives" were poorly machined. Constant rapid fire seriously damaged the rifling of the 18.1 inch gun barrels. The gunners were loath to use them.

p. 234

"Yamato must have been firing those san-shiki "Beehives," because the blast threw some planes about like shuttlecocks."

p. 275

The chief gunner told Tsukamato to get word to the men inside the big turrets that they'd better set their San-Shiki shells to burst on one-second fuses. That would throw up a barrage less than 1,000 yards away. The gunners complied. A fresh curtain of exploding water leaped up ahead of the enemy. It had no effect on the approaching Avengers. There was a remorseless professionalism about the way the Yankee pilots pressed their attacks.

Hope this helps.

Walter S

[Sewer King]

There is excellent technical detail and scale cross-sections of the San-Shiki shell in Janusz Skulski's The Battleship Yamato (London: Conway Maritime Press, 1988), page 114.

Sorry I don't have a scanner to put it up, but it describes the 46cm San-Shiki AA common projectile Model 3. Weight 1360kg, containing 1500 incendiary fragments.

In much the same form as the 46cm shell, except for its wood-filled ogive and eight tiers of the fragments behind it down to the charges at the base for delay, scatter, and bursting.

Each fragment was a hollow steel cylinder 90mm long x 25mm dia filled with rubber thermite and ignited through holes at both ends.

There is no mention of special marking or coloring to distinguish it from other rounds, although it was studded with fuzes reaching six each into the tiers of fragments.

How often could Yamato have fired the Beehive rounds for gunners to know how their bands hurt the barrels? Considering how relatively seldom she fired her main guns during the War. At least the latter were probably named for the sound it made, but I've never heard what sound the Japanese shells made.

Similar incendiary fragment AA rounds were fired against US B-24s and B-29s, but with negligible effect. I wonder if these were the same type of e fired at all in general. It's interesting that they were called "Beehive" like the American antipersonnel flechette artillery round from the Vietnam War. At least the latter were probably named for the sound it made, but I've never heard what sound the Japanese shells made.

Similar incendiary fragment AA rounds were fired against US B-24 and B-29s, but with negligible effect. I wonder if these were the same type of fragments. Airmen reported that they made attractive patterns when they burst, but little else.

[Andy H]

My thanks to you all for the information you have provided

Andy H

[Von Schadewald]

Payback for Force Z!

A realistic cinematic depiction of the Yamato's end

http://www.youtube.com/watch?v=CUl1mAjT ... re=related

All the 25mm & San-Shiki rounds in the world couldn't save her!

[Windward]

San Shiki means "Mk III" and it's not specially designed for Yamato class. There were several calibres of Mk III shells, from 460mm, 410mm to 203mm. 127mm Mk IV shell was similiar to it.

A 410mm Mk III shell contains 1200 small incendiary bombs (phosphor, vulcanized rubber, nature rubber, stearic acid, sulphur and barium nitrate), and could blow into 2527 small pieces (2846 pieces for 460mm shells).

[Windward]

Yamato's main guns fired 27 rounds of Mk III AA shells during the battle of Mariana.

During the battle of Leyte Gylf, Nagato's main guns fired 45 rounds of Mk I AP shells, 52 rounds of Mk Zero HE shells, and 84 rounds of Mk III AA shells. Yamato and Musashi both fired Mk III shells during the first air raid on Oct 24, but Musashi's captain refused his ordnance officer's request during the second raid.

regards

[Tiornu]

The idea that the Type 3's caused barrel damage seems to be another example of one man's scuttlebutt that gets accepted as fact in the West. Maybe it got started when a bomb hit on Musashi sent a fragment up a gun barrel and ignited a Type 3 being loaded; this caused serious damage.
Kongo fired a hundred Type 3's at Guadalcanal and suffered no apparent problems.

[Windward]

The idea that the Type 3's caused barrel damage seems to be another example of one man's scuttlebutt that gets accepted as fact in the West. Maybe it got started when a bomb hit on Musashi sent a fragment up a gun barrel and ignited a Type 3 being loaded; this caused serious damage.
Kongo fired a hundred Type 3's at Guadalcanal and suffered no apparent problems.

Well, it's hard to say. According to Musashi survivors' memoirs, Captain Inoguchi used this excuse (might cause serious abrasion of the barrels) when he denied the Musashi's ordnance officer's request of firing Type 3 shells.

[Tiornu]

If there were a font especially for skepticism, I'd be using it here. Every shell causes abrasion to the barrel. No document or authoritative source I know of gives any indication that Type 3's damaged the barrels to any special degree, nor is there any characteristic of the shell or propellent that would raise such concerns. Just scuttlebutt. There was a very good reason for not using Type 3's--they were useless as an AA weapon and interfered with the real AA systems. If they had any value, it was as bombardment ammo. If they were gun wreckers, why would they be aboard in the first place? Is there any source other than scuttlebutt that verifies that Type 3's were damaging?

[nota]

I fail to understand how a copper band can damage a steel barrel
copper is so much softer then steel
now rapid fire and the corrosive propellant maybe but not copper

[ChristopherPerrien]

I fail to understand how a copper band can damage a steel barrel
copper is so much softer then steel
now rapid fire and the corrosive propellant maybe but not copper

The same reason why you don't use a copper scouring pad to clean steel pots. Copper can score/scratch steel.

-------------------------------------------------------------------------------------------------------------

It seems this san-shiki shell might not have been "balanced" well, and this could cause severe, and more importantly, unpredictable wear on the barrell for each shot fired. The Japanese probably had no correction tables "built" to account for the wear/damage of the san-shiki shell to gun linings, given the experimental and little used nature of that shell.

Battleship guns are very accurate guns if all factors that affect shell flight are accounted for. However if the san-shiki shell at times caused abnormal scoring of the barrell, this "tiny factor" could cause the ballistic firing solution for regular shells to be wrong for that particular gun. Which makes that gun inaccurate and therefore useless, until either a firing solution can be worked out for the error and/or the barrell lining is replaced. I suspect this may have been the Mushashi's captain's prime concern with these shells.

Also the nature of the san-shiki shell with its very quick fuze might have caused it to fragment, or perhaps explode before it left the barrel , which would be like unevenly forcing two tons of burning scrap metal through the gun barrel, not something that the lining of any big gun would like at all.

Chris

[Tiornu]

There is no indication that that Type 3's driving bands were any more injurious than those of any other shell. There is no indication that the shells were improperly balanced or that they caused unusual wear to the barrels. The fuze was not especially quick, and I have not found any mention of any shell prematuring (except for the bomb-induced detonation, which itself may be a bit of misinformation).
Is there any source other than Shiro Hosoya claiming that he overheard something about damage to the barrels? I keep thinking we're discussing something for which there is no evidence.

[Nlneff]

Perhaps we are over thinking this. The Yamato's guns were never relined in the war, and there is some question of if that was even practical in the first place, at the very least it would have been difficult. You can see how conservative the IJN was in using up the barrels by the fact that they almost never had target practice, I believe Yamato herself fired about 6-7 salvos during the entire war in Gunnery practice. So any damage to the bores at all must have been considered meaningful. If the Gunnery officer thought the shells were useless against aircraft (Probably correct) then he could have legitimately not felt the normal bore erosion of shooting the shells was worth it, preferring to preserve barrel life in case they ever got into the surface battle they were designed for. (Ironically the lack of practice that kept the bores in good shape would probably have severely reduced their effectiveness in battle, but I digress.)

Combine that with translation difficulties, and I think thats a possible interpretation as well.