Idle curiousity about 16" battleship guns

[Mike Irwin]

"An old Navy gunner once told me that the crew chiefs of two gun turrets on a cruiser were debating which one of them was a better shot. While shelling some shore target, they decided to aim at a smokestack, to see who could hit it dead center from 6 or 8 miles away with a round from their 8" (?) guns."


I'd view that story with a grain of salt. Quite a few, actually.

The turret captains only control the loading sequence.

The gun laying and firing is done from an entirely different part of the ship.

 

[Mike Irwin]

"Any idea of the MV/Energy stats for that puppy?"

Yeah. ENORMOUS.

Average velocity for a gun with some rounds through it would be about 2,425 fps.

The super heavy projectiles weigh 2,700 pounds, or 18,900,000 grains.

So...

2,450 * 2,450 = 6,002,500 * 18,900,000 = 113,447,250,000,000

Divide that by 450,400 and you get...

251,881,105 foot pounds. That's 252 MILLION foot pounds of energy.

Or, 12,590 foot TONS of energy.

 

[Parker Dean]

They can be accurate when new, but you also have to factor in the rate and duration of fire these guns went through in combat. Shelling a beachhead can involve continuous fire for up to an hour. Imagine what that would do to your .308 barrel?

I was reading a story recently about the U.S. destroyers supporting the Inchon invasion during the Korean war. The 5" guns on these things had seen so much use during action during the end of WWII at Iwo Jima and Okinawa that they couldn't provide accurate fire past the beachhead anymore. A few of them got into real trouble when getting as close to the shore as they could to reduce the ranges.

I read somewhere that the BB's got new tubes every 400 full-power rounds. Target practice, close range shelling, etc were frequently done at reduced power to save the tubes.

I also read somewhere that the Navy still has new 14 and 16 in. tubes in storage (there IS a reason for all those last-two-generation museum BB's scattered around. Except the Texas of course, she's faaar too old to even be seaworthy)

 

[Triad]

Since when does age have anything to do with how seaworthy a ship is? They have sailed the Constitution at least once in the past hundred years I thnk.

 

[Mike Irwin]

"Since when does age..."

It can actually have a LOT to do with it, especially if the age is combined with improper or delayed maintenance.

The ONLY reason the Constitution was considered to be even remotely seaworthy is because they spent a lot of money replacing bracing devices called "diagonal riders" that were part of the original design, but which were removed over the years.

 

[Mk VII]

the addition of Swedish additive to the powder bags cut the erosion rate considerably in the 1980s.
Last I heard, Watervliet Arsenal was still set up to make replacement tubes, if needed.

 

[Dain Bramage]

There is another use for surplus 16" AP shells. Emptied of explosive, they make excellent pressure chambers. I saw a few being used for this purpose at the University of Washington.

I wondered if the liberal blissninneys knew we had shells, albeit inert, on campus. Just a few things that made me go "hmmm", along with the NROTC armory at Huskey Stadium and the working nuclear reactor (since decommissioned).

 

[Jammer Six]

251,881,105 foot pounds. That's 252 MILLION foot pounds of energy.

Or, 12,590 foot TONS of energy.

I gotta think that would be capable of delivering a one shot stop fairly consistantly, even if the bad guy was wearing denim, built like King Kong, and hopped up on PCP.

 

[Ironbarr]

Triad...

There is such a thing as Thin Hull.

Even with the suicidal zincs the friction of motion in salt water has its effects on steel hulls. Over time it - if not "patched, etc." can lead to a porous hull. Actually, one of the four BB's was put out of commission early due to this problem (and probably other things).

BTW, folks, I have a great overhead photo of USS Iowa's broadside. I have no website now so anyone wants it, PM/email me.

Oh - yes - there is local control available in the turret - fire control radar, etc. not infallible, you see.
.
-Andy

 

[Frohickey]

BigG said

Any idea of the MV/Energy stats for that puppy?

2700 lb projectile (18.9 million grains) going at 2500FPS is 262289648.14 ft-lb of energy.

 

[Mike Irwin]

Yes, there is local control, but again I seriously suspect that two turrets taking local control during a fire control mission, simply to prove who's the better shot, is something that never happened.

 

[Frohickey]

I gotta think that would be capable of delivering a one shot stop fairly consistantly, even if the bad guy was wearing denim, built like King Kong, and hopped up on PCP.

Of if the bad guy was wearing torn pants, no shirt and shoes, was recently made angry by an Army captain, and is emerald green in color, who just tossed an M1A1 Abrams tank like a olymic hammer throw event...

 

[BigG]

Yeah, Frohickey, but what about the free recoil stats?

 

[Ironbarr]

Jammer Six...

Consider those numbers times six - the broadside salvo. The impact area would warm the cockles of the hearts of most CB's doing site preparation for new buildings.

BTW: IIRC, that broadside causes a 100 foot ship's displacement which, of course, must be cranked into that old (MK1Mod 0 ??) computer else the next load falls short.

-Andy

 

[Jammer Six]

Consider those numbers times six - the broadside salvo.

I'm glad you corrected me.

I would have multiplied by nine.

 

[Ironbarr]

Okay--- nine. Sorry, but I've been retired 35 years and even though I just had cataract s removed and now have 20/20 and had just looked at the aforementioned photo with 9 guns blazing, the MK 1 Mod 0 between my ears clocked a 6. Yeah, I know - but I have to blame it on something so I'll blame it on last week's 71st birthday. :banghead:

Thanks for the correction.

-Andy

 

[robear]

You're not saying that the ship moves 100' sideways during a 9-gun broadside salvo are you??

This was rather extensively discussed on TFL quite some time ago..
A good discussion..

See here: http://thefiringline.com/forums/showthread.php?threadid=102622

R

 

[P95Carry]

I think Ironbarr's Iowa pic will be the same one Preacherman posted on my muzzle flash thread ....... impressive ..... incredible shockwaves too.

 

[robear]

Beautiful pic...

A shame they were mothballed...

AT3 Robear
USN 93-97
SeaOpDet Miramar
USS Kitty Hawk CV-63
USS Nimitz CVN-68

 

[Ironbarr]

Photo is correct.

I'm having a bad day - forget my numbers - been too long.

 

[OEF_VET]

Ironbarr,

Your numbers are not incorrect. The pic shows just six of the nine guns firing. IIRC, I read awhile back that they can't fire all nine guns at once, lest the ship tip over, or some other catastrophic event occuring, such as the extreme recoil causing hull problems.

Frank

 

[Festus]

Hello!!!! Here is some info on 16" guns from a website on the guns that protected NYC Harbor in WW2:

http://www.geocities.com/CapeCanaveral/Hall/4634/16ingun.html


Probably more info than you want to know.


Especially interesting is the front glacis from a Yamato class BB that was easily penetrated by a 16" gun removed from the South Dakota. The glacis is the front shield on the main turret that is usually considered the heaviest armor on the ship.

As an Army Reservist in the 70's I belonged to a unit stationed on the post where the bunkers shown in the pictures still exist. The bunkers were huge!! They had trains to move the shells into the bunkers from the ammo storage.

Of course by that time the guns had been cut up and my unit had only 105 howitzers. We used to shoot sub caliber training devices into the backside of the bunkers untill the Natl Park Service threw us out.


Sorry to ramble.

 

[Mike Irwin]

"lest the ship tip over, or some other catastrophic event occuring, such as the extreme recoil causing hull problems."

Won't cause the ship to tip over. It can stress the turrets and mounts, though.

One of the biggest reasons why they don't touch off all 9 simultaneously is simply because of the blast from all three tubes in 1 turret would interfere with the trajectory of the shells. I forget the term that's used to describe this, but IIRC I believe that normally firing sequence was left, right, center, each about one half a second apart.


"Especially interesting is the front glacis from a Yamato class BB that was easily penetrated by a 16" gun removed from the South Dakota. The glacis is the front shield on the main turret that is usually considered the heaviest armor on the ship. "

That plate was found in I believe the Kokura Ship Yard, and was supposed to have been installed on the Shinano, the third Yamato class ship. The Shinano was, however, converted into an aircraft carrier after the Japanese losses at Midway.

The plate was mounted vertially and shot to simulate plunging fire at some specified distance.

It is displayed at the Washington Navy Yard Museum. It's impressive as hell to see where the 2,700 pound super heavy burned right through the plate.

Ah, here we go...

A photo of said plate...

Visit this website for some more photos of the plate, and a write up about it:

Shinano armor plate

 

[Parker Dean]

Unfortunately the site doesn't say at what range that the plate was penetrated and the link to "more info" doesn't work.

Anyway there's no doubt that even the best armor can be penetrated, the question is at what range? As a rough guess I doubt the Yamato class would be immune to the U.S. 16in 50cal Mk7 with the later 2700lb AP shell at ranges less than 20,000yards. The turret faces might go a bit less, but side armor and barbettes would likely be pentrated by that time. Also I suspect that they would not be immune to plunging fire beyond 29,000 yards. I'm just rough-guessing here based on the immune zones that U.S. BB's were designed for vs the U.S. 16in/50.

However it should be noted that the best U.S. BB, the Iowa class, is probably not immune to the Yamato's 18in 45cal's at ANY range. At best the immune zone would be only a few hundred yards wide IMO, probably in the 26-27,000 yard range.

 

[Moparmike]

P95, thanks for the pic! My parents have been wondering what I want for Christmas, and now I have the perfect idea!