All or nothing concept?

This terminology was often used in constructions of battships during the inter-war years. What exactly does that mean?

 

An All-or-Nothing ship has its armor concentrated in single thick layers, while "incremental" ships will have multiple protective decks and upper belts of intermediate thickness.
The first dreadnoughts with the AoN scheme were Nevada and Oklahoma. The barbettes retained their full thickness all the way from the gunhouses down the armor deck. All decks above the armor deck were thickened only enough to satisfy structural demands. There was no side armor above the main belt. No ship has ever been 100% AoN, and that includes these two; they had a thickened deck below the armor deck to catch splinters from shells detonating against the main armor.
The last incremental design was Bismarck. The deck protection was split pretty evenly between the armor deck and the upper deck. Above the main belt was an upper belt of intermediate thickness. Behind this upper belt, the barbettes were much thinner than they were above the upper deck.
The advantages of the incremental scheme are an increased protection against small and medium shells and against HE shells of all types. The advantage of the AoN scheme is the increased protection against large shells.
It bears repeating that no ship is entirely AoN or incremental. The Littorios are very hard to classify, as they seem to be halfway between the extremes.

 

Far be it from me to challenge you on a question concerning warships, Richard, but I did have a rather different impression of what 'all or nothing' meant. I had understood that it referred to concentrating all armour protection on the vital areas of magazines, engines, boilers, turrets and a few bits like control towers, thereby creating a central 'citadel' while leaving the rest of the ship unprotected. Is that wrong?

Tony Williams: Military gun and ammunition website and discussion
forum

 

I think the basics of the All or Nothing concept was that you protect an area with the thickest armour possible or no armour at all. The idea being that thin armour will not stop heavy shells but will provide enough resistance to set off such shell. If they hit an unarmoured section the heavy shell will go through without going off.

That is my understanding of the concept.

 

The bow of an AoN ship was usually unarmored, but the stern had to be protected--the steering gear is there, along with the prop shafts. In fact, the ships with the heaviest stern armor by far were AoN ships. Also, the modern British battleships had armor in the bow that was, in some places, just as thick as their citadel armor. This unusual feature appears to have resulted as a reaction after the Nelson design. Nelson was the most purely AoN dreadnought, and from early on, the RN seems to have had buyer's remorse over her armor scheme.

 

Mine, too, Ebar. Makes sense, too, when you think about it.

 

That sounds reasonable. I hate to be the sailer working in the "nothing" section of the ship during a fire fight, knowing that an 16-inch shell can go through my room any time.

 

It's better than working in a 'some" section of an incremental design. The 16in shell can still go through your station, but it is more likely to explode there, not to mention the chucks of broken armor it will be carrying with it. During the firing trials performed on Baden after WWI, a 15in shell struck the 170mm casemate armor. The shell continued down into the hull and exploded, while the dislodged plug of 170mm steel shot directly across the ship, completely across the ship, and didn't stop until it had stamped a big dent in the 170mm armor on the other side.

 

Nice posts everyone, I am learning a lot. However the American navy used wooden decks on it s carriers. All except the Brits did this. The Brits assumed that the carriers would be part of a Battleship Battle Group, therefore must be able to withstand 14-15 inch rounds. Funny how the Japanese used 14-15 inch naval rounds with fins attached to them to bomb their targets.
The American Navy, I can't speak for any of the others; because I simply do not know, changed this around the Korean War timeline.

I'm not sure if this fits to the All or Nothing concept but I thought this would be related to the placing the heaviest armour plates on the Battlewagons.

 

It's more instructive to discuss British carriers in terms of armored hangars rather than armored flight decks. The hangar was armored on every side, including the bottom, and the only portion of the flight deck to be armored was that directly above the hangar. The decision to armor the hangar has no relation to the development of all-or-nothing protection for battleships.
British hangar armor was meant to defeat 500-lb SAP bombs and 6in shells. As far as I know, no armored box was ever hit by a 500-lb SAP bomb or a 6in shell. The decision to go with the armored box design was a big mistake. DK Brown has identified only one kamikaze that would definitely have penetrated into the hangar if it had not been armored, and there was only one bombing attack that the flight deck armor ever defeated. The RN would have been much better off with more Ark Royals rather than Illustriouses.

 

Armoured Flight Decks.

http://www.mckennas.demon.co.uk/british.htm

http://www.fleetairarmarchive.net/Ships ... epage.html

http://www.xsouth.freeserve.co.uk/hms_ark_royalww2.htm

I disagree on your research materials, check these sites I have listed for your perusal. Enjoy.

Then again my information, however well researched is not infalible. I can only post what I have available from the net. I have also found history books, on some subjects, to be sorely lacking in accuaracy.
Anyways here's what I have for you to read.

 

Armored boxes

Two things garenteed to start an argu... sorry, difference of opinion

1. What sank the Hood?

2. Was the armoured box on the RN's Illustrious and later carriers worthwhile?

Tiornu, have you been able to retrieve your post about this on the Warships1 board?


:smok:

 

Re: Armored boxes

Most of the content from warships1 is now available at http://www.navweaps.com/ . The tech board is there, including my piece on the armored-box carriers. It attempts to correct some of the misconceptions surrounding the Illustrious class, such as the idea that they were meant primarily for operations in the Mediterranean, that the air group was reduced in order to gain armor, and that the ships were well suited to dealing with kamikazes.

 

Wow! That Ark Royal site is really off! I think the designers would be surprised to learn the ship had flight deck armor. "Who put that there...?"
If you want a complete survey of battle damage to the armored-box carriers, see Brown's Nelson to Vanguard.

 

Armour in the bows

Got to admit, I thought All or nothing meant that - armour or no armour.

Intresting thing here is the armour in the bows - did this have any coonection with the KGV's requirement for A turret to fire at 0 degrees and what the armour in the bows like in Vanguard and the Lions?

 

Re: Armour in the bows

Nelson was the most purely AoN dreadnought design. During the 1930's, the British got really anxious about the limited extent of the armor. They wanted to add depth to the belt protection, and they wanted to give some protection to the bow. The belt augmentation idea never came to fruition, but Nelson did get some armor added to her bow during wartime repair of some battle damage.
So the bow armor was not at all connected to the forward-fire requirement in KGV. Lion and Vanguard had the same arrangement as KGV, despite the famous bow development in Vanguard.
How absolute is AoN? Well, all the US "Standard" ships, which introduced AoN into dreadnought design, had a splinter deck up to c2in thick, and the lower barbette beneath the armor deck was something like 3.5in. All US AoN ships had fairly thick lower barbettes.
Nelson had D steel protective plating 1.5-2in thick on several surfaces. The thin portion of the deck armor and the uptake protection may also be seen as not really all or nothing. Yamato was probably the next-most extreme, but she had a bomb deck outside her citadel and thickened plating protecting the funnel.
However, looking at the exceptions does not cancel the obvious difference between AoN ships and the standard incremental schemes of other ships.

 

Another theory that effected the armouring of warships was immunity zone theory.

 

Which was...??

 

Immunity Zone Theory basically runs that there is a hypothetical band that in which beyond X range shells striking the side armour and inside Y range shells striking the deck will not penetrate.

The word 'Immunity' is in this case rather misleading since a shell weighting a good chunk of a ton and arriving at somewhere between Mach 1.5 and Mach 3 is never going to ping off and is always going to do damage but in theory the chances of an instantly catastrophic penetrating hit are most reduced.

It always made a better theory than practice since the immunity band of say HMS Nelson will be different if she is being shot at by Scharhorst rather than Bismark. But it was a factor in inter-war warship design.


Read this for a more detailed explanation
http://www.navweaps.com/index_tech/tech-069.htm

and then read this if you want an amusing explanation of how warships are designed.
http://www.navweaps.com/index_tech/tech-035.htm

 

Yes, IZ is always theoretical and limited in application even its own definition. Basically it depicts probabilities of penetration into the vitals. I think it was during the Battle of Savo Island that a Japanese 8in shell struck a cruisers ice cream machine and deflected downward into the hull; I can assure you that the USN never ran an IZ calculation that accounted for ice cream machines.
The IZ concept does not apply well to incremental ships. The way their decks are arranged, they give very poor protection from plunging fire regardless of the total amount of deck plating.