Idle curiousity about 16" battleship guns

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Parker,

Check here for data on armor penetration of the 2,700 lb super heavy...

US 16"/50 naval rifle



Check here for data on the Japanese 18.1" guns

46cm/45 Type 94 naval rifle


What most people don't realize is that while the Iowas were armed with 16" guns, they were only armored to go up against ships with 14" guns.

The never-built Montana class battlships would have rectified that, though.
 
It's a damn shame that the Montana class ships were never built, but I understand why they weren't. The only real use for battleships was to shell coastlines, and armor didn't matter a whole lot.

The HMS Ark Royal proved that battleships were no longer capital ships before we ever got into the war.
 
i don't see where anybody else posted this but,,,

i just caught a thing about these guns and the full powder charge was reported as 660 lbs per shot,,,

i also remember a ship, possibly the hoel (ff, i think) that had an 8" gun mounted on her bow in the 70's

rumor had it that after every test fire, they had to go in for structural repairs

it was the only ship in the fleet at the time with an 8 " mounted,,, IIRC

and

HAPPY BIRTHDAY IRONBARR!!

:D
 
Mike,

Thanks for clarifying that somewhat. I knew that there was a reason why they didn't fire all nine at once, I just couldn't remember the reason. I'm definitly no expert on the ships of the line, nor do I play one online.

Frank
 
280PLUS...

Birthday? Oh no! :eek: Not again! Too, too many. :)
Thank You.

(And now, to qualify this reply - My BD present to myself is a trip to the range and some holing of paper.) :D
-Andy
 
P95, thanks for the pic!
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You're welcome Mike but gotta own up and say no credit to me! Preacherman posted it on my other thread and so I ''retrieved'' it .... plus Ironbarr has a copy too. It is tho probably one of the most dramatic pics I've ever seen of the big guns in action.

What amazes me is that it is possible to consume near 1/3 ton of propellant, keep that confined, shove that 2700 lbd ''lump'' outa the tube .... and - still have a ship of your own in one piece ...... wonder what ''CUP'' figures might be registered in the breech eh!!
 
i also remember a ship, possibly the hoel (ff, i think) that had an 8" gun mounted on her bow in the 70's
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I don't remember the name of the ship, but it was a DD (Destroyer). Instead of the typical 5" mount, they put an 8" mount on it. The result was hull cracking, etc. The ship just wasn't built to withstand the pounding of the 8".
 
Just for grins and giggles...

This is what the Montana class ships would have looked like...

USbb67_Montana_LD2.jpg



USbb67_Montana_LD.jpg



Those photos are, once again, from www.warships1.com, the best warship information site on the web.

The Montanas were designed after rumors began to circulate about the Japanese super battleships, and were in some ways sweeping changes from previous American naval thought.

First, they were too wide to transit the Panama Canal. One of the reasons why the Iowas have such a sleek greyhound look is because of the requirement that they fit through the canal.

Second, they were finally armored against ships firing shells larger than their own. The Iowa, South Dakota, and North Carolina classes had all mounted 16" guns, but were only armored against ships with 14" guns.

Third, they weren't fast enough to escort the fleet carriers. Even though prior to the war the Navy didn't look at the fleet carriers as viable weapons in their own right, it still wanted all the ships of a task force to have the same relative speed. The Montanas, though, would only have been able to do 28 to 29 knots as designed.

Finally, their sole purpose would have been to seek and destroy the Japanese super battleships, one of the reasons why the Navy went back to a 4-turret arrangement.

They would have been impressive ships, no doubt, but by 1943 it was pretty clear that while Apatasaurus was an impressive dinosaur, it was still a dinosaur. :)
 
What they found during the drop tests after the Iowa was that when they emptied some amount of propellent from it, it disrupted the way the sticks where organized, and a very small fraction of them will detonate on impact in that case.

In the case of the Iowa, they ultimately figured the hydraulic ram set off a partial bag.

I'm not certain what they did to fix the problem, the article didn't say.
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I saw that article. The rammer was manually operated, with a kind of variable throttle-style control. The projectile would be rammed in hard to seat it against the rifling, and the propellant was pushed in gently.

The investigators looked at the damage to the rammer, and were able to establish its position at the moment of the explosion. It turned out to be farther forward than it should have been for pushing in the propellant. They calculated the force/acceleration the rammer would have put on the propellant at that position, and conducted drop tests on propellant bags to recreate an explosion (it happened again).

They also determined the rammer operator was new. Their best conclusion was that he wasn't paying attention, or was in a rush, and just rammed the propellant in too hard. BTW, this wasn't Clayton Hartwig, the initial scapegoat. Hartwig's body was actually found several decks away from the loading room.
 
citizen...

See what happens when you throw some wrong information out? All the pros jump in to correct it. Makes for interesting and informative reading.

(As if I did it on purpose, huh?) ;)

-Andy :D
 
What most people don't realize is that while the Iowas were armed with 16" guns, they were only armored to go up against ships with 14" guns.
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Not entirely a true statement.

The Iowa and South Dakota armor schemes are effectively the same. at the time of design this gave protection against the 16in/45 firing the 2,240 lb shell between 18,000 and 30,000 yards as per the requirement stated in a directive issued 14 Apr 1938.

Moving to the later 16in/50 the immune zone shrinks to 21,700 on the inner edge but grows to 32,100 yards. The extension of range is the result of the higher velocity of the 16in/50 causing a flatter trajectory which in turn changed the impact angle on the deck armor. Basically the lower velocity shell would impact more vertically at extreme ranges and defeat the deck armor while the higher velocity round would come in more from the side and sort of "skip off" the deck.

Then when the 2,700 lb shell was introduced the immune zone shrank to 20,200/25,500 against the 16in/45 and a measely 23,600/27,400 against the 16in/50. Of course that's still 3,000 yards, but it's also quite a reduction compared to the 12,000 yards they tried to design in.

Oh, and don't think this armor scheme is proof against the 14in/50 either. the immune zone against the 14 is between 17,200 and 33,500. Ultimate range of the 14 is in the 40,000 yard area

In any event the design intent of the SoDak's, and therefore the later Iowa's, was to protect against the 16in gun in the customary manner of the U.S. which was to protect the ship against the equivalent of it's own guns. The fact that these classes are somewhat under-amored was not due to intent but rather the result of Treaty limitations and the inevitable march of technological progress.
 
Parker,

You're of course correct; I didn't do a very good job of explaining the concepts of ship armoring.

There are ranges at which just about any heavy cannon would be able to penetrate the armor of another ship.

Even the ancient 12"/50 from the Arkansas could have penetrated Iowa's side armor at up to 14,000 yards, and the guns and shells from the Alaska battle cruisers, the 12"/50 Mark 8, would do a lot better.

The concept of an immune zone is one where a level shot won't tend to penetrate the side armor or the deck armor.

Closer and the side armor will be penetrated, farther away and the falling shot will penetrate deck or glacis armor.

The idea of armoring a ship is based on engaging like ships at typical distances for the particular weapon that your ship is carrying.

For the optical sighting systems in use when the American post Washington Treaty battleships were designed the armor roughly equated to an immune zone for a 14" gun at considered practical engagement distances for those shells.

The advent during WW II of radar directed ranging and gunnery significantly changed that equasion.

South Dakota's and Washington's performance at the battle of Savo Island, or Duke of York's hitting the Scharnhorst on the first salvo at the Battle of North Cape, is a good example of how significantly radar changed the way big gun ships did battle, and the ranges at which they did it.
 
Another nice picture of a battleship firing - this is the New Jersey off the coast of Australia in 1990 (courtesy of warships1.com, of course).


attachment.php
 
Actually a 9 gun broadside could be and was fired. Page 67 0f "Iowa Class Battleships" by Robert F. Sumrall shows Iowa firing one on 15 August 1984. I was aboard Missouri in 1953 when she fired a 9 gun broadside. I was in Forward Secondary Plot at the time & we had to hold on to keep from being bounced around.
 
FWIW: The original powder for the 16"/50 cal. was coded D839. Individual grains ran roughly 2" long, 1" in diameter, and possessed seven 0.060" perforations. Web thickness ran 0.193" to 0.197". Original acceptance specs demanded that velocity deviations be held within +/-10 fps. Some lots managed to achieve +/-5 fps during WW2. By 1984, it had degraded to +/- 32 fps...leading to the subsequent repacking efforts.

The powder from the 16"/45 cal. was D846. Web thickness ran 0.158" to 0.169". The powder was remixed in 100,000 pound sections and combined to form lots of 600,000 pounds total. They were then rebagged to a tolerance of 0.1 pound per bag.

Reduced charge propellants were derived from powders designed for the 8" heavy cruisers: D840 and D845 (flashless).

Chamber pressure has been quoted as 35,000 psi.

Blast overpressure from firing as been cited as exceeding 50 psi near the muzzle and 7 psi out to 50ft away.

The quoted delay between firing is 0.06 seconds, with the barrel sequence per turret as left, right, and then center.
 
Chamber pressure has been quoted as 35,000 psi.
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That is amazing! Considering the force needed to accelerate that ''lump'' up to speed .... and the potential amount of powder consumed . yep .. incredible. A figure of 45,000 would have not been surprising.

Must be a pretty slow powder..... well with grains that size ....... !!
 
Maybe somebody knows something about this.

I seem to recall an effort to increase the range of the 16 inch gun to 75 miles using a sabot type of round. May have just been a proposal.
 
I realize it is all a matter of displacement but still it is amazing how those behomoths could float with such thick armour plating.
 
I was on the Iowa as a Midshipman in 1957. We used to say that we threw a Cadillac overboard every time a shot was made.
 
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