My ideas for a futuristic BB

[Tiornu]

Just to let you guys know, this cross section is taken at the position of "A" turret.

The 25-lb "splinter deck" in Iowa has always left me scratching my head. Unlike most battleship splinter decks, it clearly was not intended to supplement belt protection. (It would be almost impossible to penetrate the belt above the Iowa splinter deck.) In my mind, I've stopped calling it a splinter deck and switched to "debris deck" because it can least deflect popped rivets and such. In your plan, why not do away with that deck completely and instead bulk up "additional magazine armor."
What thickness do you assign to the lower barbette?
What distinguishes STS from HY?

[maximusslade]

Unlike most battleship splinter decks, it clearly was not intended to supplement belt protection. (It would be almost impossible to penetrate the belt above the Iowa splinter deck.)

I figured I would jump on this before cRusty did.

How do you support both of these statements you just made?



Here we have a drawing of the armor scheme of the Iowa class battleships. It should be noted that in actuality the Iowas were UNDERPROTECTED as far as the norm of US battleship design. US BB's were typically designed to protect itself from its own firepower. Iowa protection was essentially a duplicate of the South Dakota's protection which would protect against the 2,240 lb (1,016 kg) Mark 5 shell. When the Iowas were designed the 2700lb Mk 8 shell had not yet entered service so the Iowa was not designed to protect against it. So in a very roundabout way, I have just described to you how the upper belt of the Iowas could very well be penetrated with impunity. In fact if you look at some websites, they describe the penetrating power of the Mk8 shell as being superior when fired from the 45 cal (South Dakota) gun versus the 50 cal (Iowa) gun owing to the 45's lower muzzle velocity.


As for your first statment about not intending to suppliment belt protection, I am just going to ask what you mean by that. The statement doesn't make sense to me.

[RustyBattleship]

The 25-lb "splinter deck" in Iowa has always left me scratching my head. Unlike most battleship splinter decks, it clearly was not intended to supplement belt protection. (It would be almost impossible to penetrate the belt above the Iowa splinter deck.) In my mind, I've stopped calling it a splinter deck and switched to "debris deck" because it can least deflect popped rivets and such.

"Splinter" protection is actually for splinters of steel and not just popped rivets. The 2nd deck of the Iowas is 4.75" of Class B armor attached to the actual 2nd deck plating of 1.25" STS with "Quilting Pins". Quilting pins are sort of like a welded rivet.

Any impact on the 2nd deck that was powerful enough to deform the STS plate underneath will cause "splinters" of steel to shear off as well as popping some of the quilting pins. So a splinter deck below was necessary to catch this deadly debris.

In old army tanks of relatively thin armor, injuries of the crew could be caused merely by a bullet or shell pushing a deep dent in the armor. The stretching of the steel inside pops out specks of metal that can be very injurious. This is called Spall. WW I tank crews had to wear face shields of chain mail to protect from it.

Then there is the rivet problem. In WW II some the M-3 Grant/Lee series were riveted and a 20mm Soluthurn could punch a rivet through and ricochette it around the inside. But tanks are too small to have an interior Splinter plate and today's tankers (starting in the Korean War) started wearing body armor just for that purpose.

On a large warship, given the room, any sort of splinter TRAP is very welcome. When I was tasked to design armored vents for the Iowa class in the 80's to lead into the certain critical spaces (such as the 5"/38 upper handling rooms), I designed them to have at least two 90 degree turns in them to act as splinter/fragment traps.

When I have the time, I'll dig out a photo I have of a couple of them.

[Tiornu]

So in a very roundabout way, I have just described to you how the upper belt of the Iowas could very well be penetrated with impunity.

There's no doubt that the Iowa belt is penetrable, but look where the splinter deck is. Almost every trajectory through the belt would have the shell extending below the splinter deck before it detonates. That's why I say it's almost impossible to have penetration above the splinter deck.

In fact if you look at some websites, they describe the penetrating power of the Mk8 shell as being superior when fired from the 45 cal (South Dakota) gun versus the 50 cal (Iowa) gun owing to the 45's lower muzzle velocity.

That applies to deck penetration, and it's correct. Iowa was unusual in that there was always provision for controlling gunnery at a muzzle velocity of 2300f/s--that is, it could perform as a 45cal gun. I don't know of any foreign design that had this capability. There were always ships firing with reduced charges, but I'm not aware of any intended to do so against ship targets.

As for your first statment about not intending to suppliment belt protection, I am just going to ask what you mean by that.

Splinter decks were, from pre-dreadnought days, intended to stop splinters from shells penetrating the belt armor. They were not meant to stop splinters from shells penetrating the decks overhead (for the simple reason that shells did not penetrate horizontal decks at the battle ranges of the day). After the Americans developed All-or-Nothing deck protection, and pretty much everybody followed suit, the splinter deck continued to serve primarily as a back-up for belt protection. A 1.5in deck will stop a good number of lateral shell splinters, but the nose piece of a descending shell is something entirely different.

So a splinter deck below was necessary to catch this deadly debris.

That's why I think "debris deck" is a far more appropriate term. It may stop debris, but it's not even considered thick enough to stop 8in shell splinters. (I believe 19-20mm was considered necessary for that duty.)

[RustyBattleship]

I'm going to make this into three postings as it addresses 3 kinds of fragment (armor) protection.

The first one is an air supply vent duck leading into a 5"/38 upper handling room of the USS New Jersey.

The open end on the right is where the normal thin sheetmetal ductwork would attach to. A fragment or bullet entering on this end would have to try to make a 90 degree turn to the left then a 90 degree turn to the right to enter the handling room.

The vent armor is 1.5" thick HY-80 and the existing handling room armor is 2.5" thick STS.

I also added curved plates of 16 gauge stainless steel in the interior corners to allow for a free flow of air but were too thin to deflect an intruder of any dangerous velocity.

[RustyBattleship]

My second example of adding additional "frag" armor to a ship was what we had to do with some of the 963 Class Destroyers. In 95% of the cases it was adding thicker aluminum plates to existing bulkheads as "applique" armor.

The thickness depended upon how thick the outer bulkhead was and how many other bulkheads were in between the critical space and the outer bulkhead with the applique armor.

It is still classified (I think) as to what the thicknesses really were, but this picture of adding applique plating around the Refueling-at-Sea fittings could only be pleasurable to lovers of giant jig-saw puzzles.

[RustyBattleship]

For my final Rube Goldberg of frag armor, in order to reduce topside weight the armor trunks to protect the cables and waveguides going UP the mast were thick aluminum plates with thick resin impregnated "Kevlar" glued to the inside.

I'm not too much of a fan of Kevlar alone. I once put a bullet through 3 sheets of it, each 3/4" thick for a total of 2 1/4".

But I cheated. I used an M-1 Garand in .30-06 with black-tipped armor piercing bullets.

[maximusslade]

There's no doubt that the Iowa belt is penetrable, but look where the splinter deck is. Almost every trajectory through the belt would have the shell extending below the splinter deck before it detonates. That's why I say it's almost impossible to have penetration above the splinter deck.

It seems you have misconceptions as to how the "all or nothing" deck armor is supposed to work. The armored deck is not the deck that is supposed to cause an AP shell to detonate. That job is left to the weather deck (aka bomb deck). The weather deck armor is juuuust thick enough that an AP shell passing through it will be triggered. Once triggered, about .003 (or something like that) seconds later the shell explodes, at which point it will be in the space above the armored deck. The splinter deck, as Rusty has already explained, is there to catch fragments caused by any deformation of the armored deck or its STS backing. The splinter deck is not designed to contain a first order penetration and explosion.

Splinter decks were, from pre-dreadnought days, intended to stop splinters from shells penetrating the belt armor.

Splinter decks did not exist in the days of predrenoughts. The first "all or nothing" warship was USS Nevada, launched 1914. But that is just semantics...

[Tiornu]

The armored deck is not the deck that is supposed to cause an AP shell to detonate. That job is left to the weather deck (aka bomb deck).

You are mistaken. The purpose of the bomb deck is to minimize bomb damage. It is not intended to prevent the impact of intact shells with the armor deck, which would be a rather vain effort since the bomb deck doesn't cover all shell trajectories to the armor deck. In a discussion with Adm King and the General Board, Capt G L Schuyler stated outright that armor thickness applied to the weather deck gives less protection against gunfire than the same thickness concentrated on the armor deck. The centerline deck protection in several US battlesihps was thinned in the "trajectory shadow" of the bomb deck simply because the initial impact was expected to result in a lessened striking velocity with the armor deck, though apparently no account was made for deflection of the shell which actually aids in penetrating the main armored deck. The bomb deck was a negative factor in protection against shells.

Splinter decks did not exist in the days of predrenoughts. The first "all or nothing" warship was USS Nevada, launched 1914.

All protective decks in pre-dreadnoughts were splinter decks, unless you'd like to make exceptions for the sloped portions of turtledecks, especially over the steering gear where there might be no appreciable vertical armor. The purpose of the thickened decks in those ships was to defeat splinters. Upper belt and casemate armor was fitted expressly to prevent the decks from having to defeat even a slight downward shell trajectory. Nevada was the first dreadnought to have an armor deck intended to defeat direct impacts, though earlier ships had very thick armor on the lower deck to protect the steering gear. The British acknowledged the difference in protection by distinguishing their deck plating ("protective plating") from horizontal protection of the turrets and conning towers ("armor"). The "armor" was a Krupp non-cemented armor, while "protective plating" was nickel steel or HT steel. After WWI when the British began their AoN designs, the terminology changed, and the concentrated deck armor really was "armor."

[maximusslade]

Battleship.org states:

The deck consists of three parts, the bomb deck, the main armor deck, and the splinter deck. The bomb deck is 1.5 inches STS plate, the main armor deck is 4.75 inches Class B armor laid on 1.25 inches STS plate and the splinter deck is 0.625 inches STS plate. The bomb deck is designed to detonate general purpose bombs on contact and arm armor piercing bombs so they will explode between the bomb deck and the main armor deck. Within the immune zone, the main armor deck is designed to defeat plunging shells which may penetrate the bomb deck. The splinter deck is designed to contain any fragments and pieces of armor which might be broken off from the main armor deck.

Friedman's U.S. Battleships states:

[Referring to the bomb deck]Armor piercing shells would penetrate easily enough, but the bomb deck would initate their fuse action, and they would burst harmlessly against the main armor deck. In addition, shells passing through the bomb deck would find it more difficult to penetrate the armor deck below it.

Perhaps I dont know how to read, but from what I have just read the bomb deck, while perhaps not its primary purpose, will serve as a burster for incoming AP shells and bombs.

[Tiornu]

You gave your rendition of what how AoN deck protection is "supposed" to work. I described the "purpose" of a bomb deck, and I quoted primary source material on the subject. Might the bomb deck cause a shell to explode before reaching the armor deck? It's kind of irrelevant. Any trajectory that shallow would not penetrate the armor deck anyway.
We've already agreed that the so-called "splinter deck" is useful against debris. Against shell splinters, it's useless.

[RustyBattleship]

Battleship.org states:


Friedman's U.S. Battleships states:


Perhaps I dont know how to read, but from what I have just read the bomb deck, while perhaps not its primary purpose, will serve as a burster for incoming AP shells and bombs.

You know how to read all right. Though I'm jealous of Friedman's ability to write books on government time with all the official archives at his fingertips, he is pretty accurate. The only thing about his writing that really disturbed me is his book on Desert Storm that gave away (partially) one of the secrets to RADAR stealth.

But what do I know? I was only the structural project leader and configuration manager for all the structural modifications and additional armor on the Battleships in the 1980's. I only had to give myself a crash course in studying all of the construction drawings as they were still being cataloged in plan files or squint at a microfilm monitor. I only had to contact older Naval Architects and armor experts (by phone mostly) to confirm my interpretations. I only had to design (either drawing it myself or instructing draftsmen and other engineers and technicians) all the extra armor added to the ship.

I only got frustrated from the big shots from NAVSEA who insisted I call the extra armor merely "Fragmentation Protection." As an ex-tank driver, having thick stuff between me and incoming is ARMOR.

I have a bookcase full of the same books you guys read. But I was the one who had to work with the existing construction and provide new structures (and armor) to meet the requirements of modernization and protect the crewmen inside.

Also, for my first 10 years as a Civil Servant, I actually swung a sledge hammer building or replacing similar structures. So I have a true "Hands On" experience.

Oh h*ll. I'm running off at the mouth again and boring the heck out of you guys. I'll just pour myself another Vodka and toast to my mother-in-law who passed away two days ago on my daughter's birthday.

Good night.

[maximusslade]

Sorry about the recent loss Rusty.

It being 2am here, and being tired, I am forced to ask if you are chastizing us for being young, know nothing whippersnappers or if you are if you are ranting about Friedman's use of government time?

Just so you know, I've incorporated your most recent suggestions about vertical armor into my drawings. I'll be posting them tomorrow sometime.

Take care and good night.

P.S. I dont find you boring. I find your postings most entertaining and informative.

[Tiornu]

Vodka will kill you.
Drink something healthy.
Something with aspartame.

[RustyBattleship]

Sorry about the recent loss Rusty.

It being 2am here, and being tired, I am forced to ask if you are chastizing us for being young, know nothing whippersnappers or if you are if you are ranting about Friedman's use of government time?

Just so you know, I've incorporated your most recent suggestions about vertical armor into my drawings. I'll be posting them tomorrow sometime.

Take care and good night.

P.S. I dont find you boring. I find your postings most entertaining and informative.

You are all young whippersnappers, but not neessarily "know nothing" types. You all know a lot but whether you interpret it correctly or not can be irritating if you claim to be an "expert" and have gone no further than to read some books. "Knowledgable yes, Expert no"

Even I am not a "full" expert on Battleship armor because I was not given the time to study it's metallurgy and all the tests done on it. I was very fortunate in finding an armor expert up at Port Hueneme that gave me a thousand times more data on armor production AND USES than the steel factories that made it.

For example, I got a 1 1/2 page letter from US Steel that told me nothing about Class A armor. Our friend up in Port Hueneme sent me a package 1 inch thick of armor manufacture, specs, tests, hardness graphs, you name it. The original MIL SPEC for STS was lost for years until one of our welders ran across a copy (it's detail chemical requirements were removed in WW II to allow armor manufacturers more lieniency in manufacturing in the massive quantities we needed).

As for Friedman, I'm only jealous that he has free access to his material. As a matter of fact, I copied his cross-section diagrams of the Iowa class hulls and included it in a memo to all shops to identify where Class A armor was installed with the warning NOT to weld on the threat side. We do have a MIL SPEC that if welding had to be done on the face hardened side, the armor had to be annealed first and the welder had to stand behind a 5/8" thick plate of steel (with a peephole in it) as that face hardened surface could spall off in chunks the size and speed of a .45 ACP.