Jutland campaign AAR

[Agelastus]

There are six google site hits

Make sure to use the "u" in "armoured."

Results 1 - 6 of 6 for "fully armored battlecruiser".

Results 1 - 10 of about 2,290 for "fully armoured battlecruiser".

So there, Grumbler! If you Americans could only spell properly...

[Warspite]

Not quibbling with your statement, but how does deck armour contain the explosion? I thought it would deflect it upwards. I don't know much about deck armour. 

As I, a non engineer, understand it.

When the bomb penetrates the deck armour prior to detonation (as the heavier bombs do) the deck armour tends to contain the force of the blast in the hangar, increasing the damage. Additionally, as a closed hangar design the blast cannot escape laterally, so detonations in the hangar actually lead to warping of the hull.

I see. So as I understand it, this is a function of deck armour actually not stopping the bomb from penetrating and thus, perversely, containing the explosive force in a sensitive area (the hangar)?

[Agelastus]

Warspite:

Yes.

Grumbler:

I'm doing something rude here, although I'm copying in full, including the identity of the poster on the other forum.

Re: Battleship Vanguard Armor
by Karl Heidenreich on Sun Sep 14, 2008 12:59 am

Thanks to José I had to stop my reading on Friedman and pick up Raven & Robert`s "British Battleships" to learn about Vanguard. And, I must admitt, I`m begining to fall in love with this ship. Beautiful in a Hood way.

Vanguard was born from a Memo, dated March 3 1939 in which the Naval Staff looked a little bit concerned that their building program was not to be ready for the RN to stand both against Germany and Japan. The estimate they had for March 1944 was:

British Fleet capital ships in Home Waters: 10
Germany: 7 + 3 Deutschlands (5 new capital + 2 Schanhorsts)

British Fleet capital ships in Far East: 12 (2 Lions included + a lot of rusty aging ships)
Japan: 16 (including 4 Yamatos plus Nagatos, Kongos, etc.)

The Naval Staff knew that new 16" guns would be the critical path (in the building program) to have new ships ready. They expected them to be ready at the end of 1944 or early 1945. But they had in store 4 15-inch twin turrets from the Courageous and Glorious. Modernized they expected them to had some 25 more years.
The ship that would carry them, in the Memo, was estimated to be 40,000 tons and 30 knots without making any subtancial sacrifice in protection and would be a fully "armoured battlecruiser". (This is interesting because Vanguard would reach 30,3 knots with "just" 132,950 SHP whilst other contemporary new designs needed in excess of 200,000 SHP to reach similar speeds).
The protection was similar to the King George V except Vanguard had a thinner main belt and the splinter protection was more extensive. The 14 inch belt armour was capable of withstand a 15 inch AP shell up to 15,000 yards. The splinter protection was modified after Bismarck and PoW action at DS. Then, at that glorious episode Bismarck`s 15" did penetrated PoW below the belt but didn`t explode. So, in order to prevent splinters from such a hit, penetrating the magazines (A-ha-ha!  ) it was approved, on August 15, 1941, to fit a 1 1/2" inch NC armour to the longitudinal bulkheads of the main and secondary magazines in several British ships: Vanguard, DoY, Anson and Howe (It`s interesting to research if such a provision was taken in other allied ships). That increased weight in 80 tons.
Another provision was taken fto prevent loss of buoyancy and water-plane area, forward and aft the citadel, as a result from splinter damage. So they added a 2 1/2" inch and 2 inch NC armour to the ship`s side, between lower and middle decks, forward and aft of the main belt extensions, and a 1 inch bulkheads within this area. This "gave protection against bombs or shells exploding on the armoured-deck and rupture of the ship`s unarmoured structure above, by blast and splinters."
For underwater protection the system was similar to KGV Class, but as a result from PoW`s sinking the designers decided to increase the height of the longitudinal bulkheads "that formed the three groups of compartments outboard of the protective bulkhead. Thus, instead of terminating at lower-deck level, they were extended up to the middle-deck, and provided greatly improved su-division behind the armour near the waterline."

Armour weights:
Belt........................4,666 tons
Bulkheads................ 516 tons
Barbettes.................1,500 tons
Main deck................4,153 tons
Lower deck (forward)... 362 tons
Lower deck (aft)........ 578 tons
Additional bulkheads... 75 tons
Conning tower.......... 44 tons
Director towers......... 31 tons
Splinter belt ends...... 218 tons
Oil jacket bulkheads... 1,375 tons
Splinter protection
for cordite handing
rooms.................... 626 tons
Funnel protection...... 52 tons
Splinter protection for
bulkheads between
lower and middle
decks...................... 443 tons
Protection rings.......... 80 tons
Armour gratings.......... 24 tons
Bullet proof protection
for bridges................ 110 tons
Protection to 5,25 inch
turrets.................... 17 tons
Armour backing......... 40 tons

TOTAL: 15,000 tons

So far, this is the information that regards the armour of this incredible and beautiful vessel, the last BB ever built.

Kind regards."Tell the Spartans, stranger passing by,
that here obedient to their laws we lie.
Karl Heidenreich
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Posts: 2804
Joined: Thu Jan 12, 2006 3:19 pm
Location: San José, Costa Rica
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Anyway, although I do not have the book, it appears that the reference is from British Admiralty memos, originally. Although I tend to lurk around the warship sites, Raven & Roberts is quoted as a source for battlship data almost as much as Breyer is.

[Agelastus]

And having looked at the prices for second hand copies of Raven & Roberts book from Amazon (as it doesn't seem to be in print at the moment) I guess I will not be remedying my lack until I have bestirred myself to get a new job.

[Neil]

Weren't they designed to counter the Myoko- and Takao-class cruisers, whose power was somewhat overreported in the US?

They were designed to counter the follow-on designs (reputedly of opver 20,000 tons standard) to the Myokos then in service.  I suppose that the Takao design was what was actually produced to that rumored design, but Friedman isn't clear on that.

One wonders how effective the unusual Japanese heavy cruiser designs were at any rate.  With the inefficiency of their main armament, and the inherent vulnerability of so many turrets forward on a relatively small hull, you'd think they wouldn't perform quite as advertised.  Then again, wacky armament layouts were natural back when the Japanese won their great naval victory.

[Jaron]

They had ocean spirits guiding their weaponry.

[grumbler]

Anyway, although I do not have the book, it appears that the reference is from British Admiralty memos, originally. Although I tend to lurk around the warship sites, Raven & Roberts is quoted as a source for battlship data almost as much as Breyer is.

There is no doubt that the British initially contemplated building a battlecruiser using the turrets.  However, the Vanguard was not what they had in mind - they wanted something 10,000 tons lighter.  The Vanguard battleship design grew out of the Admiralty realization that the battlecruiser they had in mind was not going to be good enough.

I have never seen anywhere anything authoritative to the effect that the British "commonly referred to the Vanguard as a "fully-armoured battlecruiser" - though the idea of the FPBC went back to the Hood design.

The vanguard was, in fact, an upgrade of the KGV class (with its comprehensive deck armor), not the abortive 1939 battlecruiser design.

[grumbler]

One wonders how effective the unusual Japanese heavy cruiser designs were at any rate.  With the inefficiency of their main armament, and the inherent vulnerability of so many turrets forward on a relatively small hull, you'd think they wouldn't perform quite as advertised.  Then again, wacky armament layouts were natural back when the Japanese won their great naval victory.

The initial designs were horribly unsound structurally, and all of the early heavy CAs had to be rebuilt just to correct all the hull warping that occurred because of their too-flimsy construction.  The Takao design performed very well, though, as did the Aobas.  It was the intermediate designs (and arguably the Tone and Chikuma) that were of questionable superiority over more conventional designs.  The heavy torpedo armament made up for a lot of flaws, though.

[Neil]

One wonders how effective the unusual Japanese heavy cruiser designs were at any rate.  With the inefficiency of their main armament, and the inherent vulnerability of so many turrets forward on a relatively small hull, you'd think they wouldn't perform quite as advertised.  Then again, wacky armament layouts were natural back when the Japanese won their great naval victory.

The initial designs were horribly unsound structurally, and all of the early heavy CAs had to be rebuilt just to correct all the hull warping that occurred because of their too-flimsy construction.  The Takao design performed very well, though, as did the Aobas.  It was the intermediate designs (and arguably the Tone and Chikuma) that were of questionable superiority over more conventional designs.  The heavy torpedo armament made up for a lot of flaws, though.

Particularily given the Japanese torpedos.

Still, the Japanese had an odd way of doing things, going into the war.  Virtually all of their light cruisers were relics of the early 1920s (aside from the unstable Mogamis), while many of their heavy cruisers were freaks or relics.

[Threviel]

Speaking of naval history forums. Anyone know any good ones concerned with the age of sail?

Oh, and Nelsol and Rodnol were the worlds most powerful battleships a longer time than any other battleship. I would say that they were quite good.

[Alatriste]

I see. So as I understand it, this is a function of deck armour actually not stopping the bomb from penetrating and thus, perversely, containing the explosive force in a sensitive area (the hangar)?

As far as I understand it, yes, but the questions are two, armoured flight decks and closed hangars. Most Japanese carriers combined closed hangars and wooden flight decks, with 'interesting' results when a bomb exploded in the hangar (blast deflected upwards, wood planks and splinters flying all over the place, unusable flight decks... and perhaps worse still, avfuel gasses floating in the closed hangar)

Returning to armoured flight decks, the problem was not merely weight... carrier hulls needed to include hangar space, and as a result the flight deck was far higher over the water than a battleship's deck. An armoured deck meant stability problems that the British addressed including only one hangar deck, while American and Japanese carriers had two.

The rationale behind the decision was supposedly that British carriers would operate in a far more dangerous environment than the Pacific. In the North Sea and the Mediterranean heavy attacks by land based airplanes would be far more probable, and British admirals decided they needed armoured flight decks no matter the price... but anyway the worst problem with British carriers was IMHO inferior airplanes until late in the war, when they got American models. One is tempted to say than an American or Japanese carrier air group would probably have sunk Bismarck in one attack.   

[Ape]

One is tempted to say than an American or Japanese carrier air group would probably have sunk Bismarck in one attack.

Not in May 1941

[Alatriste]

One is tempted to say than an American or Japanese carrier air group would probably have sunk Bismarck in one attack.

Not in May 1941

Why not? Dead men tell no tales 

Now, seriously, I meant each one of those carriers could put in the air more than 50 attack aircraft between dive bombers and torpedo planes, all of them far better than the venerable Swordfish biplanes... Usually I have no use for Alt-His, but sometimes the method is useful.

[Agelastus]

I have never seen anywhere anything authoritative to the effect that the British "commonly referred to the Vanguard as a "fully-armoured battlecruiser" - though the idea of the FPBC went back to the Hood design.

Searching through those 2200 references on Google is annoying given the lack of sources cited. So I've asked as close as I can get to experts* and will get back to you.

*well, at least one of them is an author of books on warships.

[Neil]

Speaking of naval history forums. Anyone know any good ones concerned with the age of sail?

Oh, and Nelsol and Rodnol were the worlds most powerful battleships a longer time than any other battleship. I would say that they were quite good.

Not in the 1940s they weren't.  Their low speed was an impediment, even in the 1930s, but once the fast battleships started to show up in the late 30s, they were pushed into a niche.