USS Iowa vs. IJNS Yamato??

[Tiornu]

Yeah, I don't see the belt joint as an issue in a gun battle. It's susceptibility in the face of a torpedo detonation was known even before the ship was completed, but there was never any indication that it couldn't take a shell, which would inevitably be striking at high obliquity anyway.
There was no Class A in Iowa's turret face. This is a bit of weirdness. The Americans were using homogenous armor for both the face and roof plates; the Japanese were using face-hardened armor for both the face and the roof plates. Quirky, isn't it? I think both ships suffered for this, but I'm not sure the Americans could have made the faceplate to their satisfaction.

[Dreadnought]

Yeah, I don't see the belt joint as an issue in a gun battle. It's susceptibility in the face of a torpedo detonation was known even before the ship was completed, but there was never any indication that it couldn't take a shell, which would inevitably be striking at high obliquity anyway.
There was no Class A in Iowa's turret face. This is a bit of weirdness. The Americans were using homogenous armor for both the face and roof plates; the Japanese were using face-hardened armor for both the face and the roof plates. Quirky, isn't it? I think both ships suffered for this, but I'm not sure the Americans could have made the faceplate to their satisfaction.

Correct T,
I actually had to look that its 17" Class B over 2.5" of STS plating.:)

[Dreadnought]

There is one thing among many things about Yamato that puzzles me. It has been written before that her AA defenses could not be utilized while the main battery is in operation due to blast pressures and the effects of it upon the AA gun crews. Ever read about it?

[Tiornu]

Most of her guns were fitted with shields specifically to allow them to operate while the big guns were in action.

[Dreadnought]

Most of her guns were fitted with shields specifically to allow them to operate while the big guns were in action.

I was wondering because I have read before where they conducted tests with animals on deck while the main battery was firing as seemingly reduced them to a "red pulp" due to blast pressure. Since not much is written (outside of very few books) including the Musashi's book how much this effected the actual crews since they were not untilized together very often. Amazing how books on the same subject differ in their writings. Perhaps it is just lost in translation.

[RustyBattleship]

There was no Class A in Iowa's turret face. This is a bit of weirdness. The Americans were using homogenous armor for both the face and roof plates; the Japanese were using face-hardened armor for both the face and the roof plates. Quirky, isn't it? I think both ships suffered for this, but I'm not sure the Americans could have made the faceplate to their satisfaction.

Not quirky at all. Face hardened Class A armor is actually quite brittle for the first 30 to 40% of its depth. The angle of the turret face would be struck with a shell with less obliquity than on the sides.

We learned this lesson from observing an Italian Battleship with hardened armor on its turret face and a hit just broke a whole chunk out of it. Therefore Class B homogenous armor was considered to be less breakable but had to be rather thick to resist a major projectile strike.

Besides, that 17-inch thick Class B armor was also bolted to 1 1/2-inch thick STS plate making the whole turret face 18 1/2 inches thick.

The top is 7 1/4-inch thick Class B for machining and drilling. It is made up of 5 overlaping plates bolted to the side tops that were left untreated to allow drilling of bolt holes. The center plate is designed to be taken off for major large repairs as needed such as changing out the large ventilation ducts and fan motors. Also on both turrets II and III replenishment at sea tripods had their mounting padeyes welded to the tops. Welding cannot be done on Class A without annealing it first.

Below is a photo I took of the top of turret II on Iowa back in '06. 47 bolts were removed and their mounting holes merely capped over for weather proofing.

[RustyBattleship]

Most of her guns were fitted with shields specifically to allow them to operate while the big guns were in action.

That is correct, but they were not armored shields but just thick enough to resist overpressure and muzzle FLASH. When Musashi was attacked by our planes, that's when we found out our machine gun bullets could penetrate those shields and put the gun crews out of action. Therefore that's why most of the torpedo attacks were on one side of the ship where most of the AA guns were knocked out.

[Stitch]

I was wondering because I have read before where they conducted tests with animals on deck while the main battery was firing as seemingly reduced them to a "red pulp" due to blast pressure. Since not much is written (outside of very few books) including the Musashi's book how much this effected the actual crews since they were not untilized together very often. Amazing how books on the same subject differ in their writings. Perhaps it is just lost in translation.

Is the overpressure from a main gun that destructive? I had no idea the blast pressure was so high . . . .

[Dreadnought]

Is the overpressure from a main gun that destructive? I had no idea the blast pressure was so high . . . .

Even the pressure from a 5" gun my friend is plenty to knock you off your feet if your standing to close to it. Just imagine the shockwave an 18" gun puts out.

[RustyBattleship]

Even the pressure from a 5" gun my friend is plenty to knock you off your feet if your standing to close to it. Just imagine the shockwave an 18" gun puts out.

I've been rocked by the "overpressure" shock waves of the 16"/50 guns on the Iowa class, had my innards "jiggled' by the sharper (and closer) shock waves of 5"/38 guns and rolled over on my back by the shock wave from the blast deflector (incorrectly called a "muzzle brake") of the 76mm gun of an M-41 tank while trying to take an 8mm movie of it firing.

At least air is compressable and the shock wave (also called concussion) dissipates in a fairly short distance. But water is not compressable and shock waves in it from large explosions can cause extensive damage to a ship's hull. We take the first ship of each class and subject it to a 45,000 lb underwater explosion of HBX (1.45 times more powerful than TNT) to rattle the entire length of the ship's hull as if it was a near miss of a nuclear warhead. That is called "Grade A" shock and since the Operation Crossroads and Operation Wigwam A-bomb tests we must design our ships to withstand such a large area of shock wave.

[Gun Grape]

Is the overpressure from a main gun that destructive? I had no idea the blast pressure was so high . . . .

Artillery cannons have a set number of rounds that you can fire in a given time at high charges. This due to the sickness and physical damage that can be caused to the crew due to Blast Overpressure.

On a personal note, I had a eardrum burst, blood coming from the ear, and was picked up and tossed about 5 feet. Wrong place/wrong time when a 8in howitzer was shot using a high charge.

[Tiornu]

We learned this lesson from observing an Italian Battleship with hardened armor on its turret face and a hit just broke a whole chunk out of it.

That's interesting. Which battleship are you referring to?

[RustyBattleship]

That's interesting. Which battleship are you referring to?

I forget the name now. You will have to ask Dreadnaughthelper to jiggle his memory. But he's out of state right now so wait a couple of days.

[gunnut]

Artillery cannons have a set number of rounds that you can fire in a given time at high charges. This due to the sickness and physical damage that can be caused to the crew due to Blast Overpressure.

On a personal note, I had a eardrum burst, blood coming from the ear, and was picked up and tossed about 5 feet. Wrong place/wrong time when a 8in howitzer was shot using a high charge.

Ouch! How do you recover from burst eardrums? Do you have any lingering effects?

[Gun Grape]

Ouch! How do you recover from burst eardrums? Do you have any lingering effects?

Recovery. 24 hours light duty for a slight concussion. Cotton in the ears for drainage and to keep them clean. No loud noise exposure for a week and antibiotics to prevent infection.

It isn't that hard to rip your Tympanic Membrane (eardrum). Many people have them during an ear infection, not properly equalizing your ears on a dive/airplane and you can even rupture one during a sneeze.

Any lingering effects? From that incident I had to quit scuba diving. When the TM grew back it left an exposed nerve. At around 40 feet it feels like someone is sticking an icepick in my ear.


I'm an artilleryman. Can't hear worth a damn. And both my ears ring constantly. (Tinnitus)

My favorite line from Good Morning Vietnam

talking out in the field today. Hi' what's your name? "My name's Bob Fliber!" Bob, what do you do? "I'm in artillery!" Thank you, Bob. Can we play anything for you? "Anything! Just play it loud! Okay?""