Naval History Forums

Raven & Roberts says 23 1/2 feet Belt depth, with 8 1/2 feet below the design standard waterline.

Does “standard” mean as in Washington Standard Displacement i.e. with no fuel on board?

I have now remembered my source for the original statement that the armoured freeboard of KGV at deep load was 9ft 9in. It was the comparison of KGV and North Carolina by the RN in 1943 as reported by “U.S. Battleships: An Illustrated Design History” by Norman Friedman, page 278, https://books.google.co.uk/books?id=Y41 ... rd&f=false. I apologise for misremembering the exact total height of the belt by three inches.

alecsandros wrote:KGV had a 7.2 meters main belt, of which some 5 meters were 380mm thick , the rest tapering down to 140mm at the bottom ...

Right, but most of that was apparently above the waterline rather than below the waterline at operational displacements. Per R&R as Steve points out. If it extended too deeply below the waterline, intruding over the TDS area, it would consitute a major design flaw.

With the 170mm lower belt it was around 5.2 or 5.3 meters, IIRC.

According to the drawings the amount of taper was very gradual. At 4.8 meters it is still 320mm, at 4.9 meters its is still 300mm, and at the very bottom (5 meters) it still exceeds 200mm. The drawing has the belt at 5 meters deep and no more-unless the little pointed section on the drawing is part of the belt or a lower belt. I think its a void or part of the wood backing though. If it was part of the belt then the entire belt would have been 6 meters deep.

Gentlemen,
In the post by Dave Saxton he states that 'supercharges could be used at a pinch', what were 'Supercharges', why would they only be used occasionally and how would they affect the performance of the gun as regards range and barrel wear?

paul.mercer wrote:Gentlemen,
In the post by Dave Saxton he states that 'supercharges could be used at a pinch', what were 'Supercharges', why would they only be used occasionally and how would they affect the performance of the gun as regards range and barrel wear?

Super charges were larger and hotter powder charges. They were conceived mainly to increase the muzzle velocity and therefore the range of the 15"/42 guns which did not have 30* elevation capabilities such as the Rs and some of the QE's. At 20* elevation the max range was only about 21km, so one of these old gals escorting a convoy could be out ranged by an enemy cruiser or battleship, making it helpless to protect the convoy. In the Med the main battery was out ranged by the Italian 6" gun. The use of supercharges could increase the range to 26.5km. The increase in muzzle velocity improved belt penetration but decreased the angle of fall against decks. It also greatly increased the wear and tear on the gunlining. I would suspect it altered the dispersion properties as well. They were only to be used in an emergency. In the event none of these battlewagons ever used them, and they were not issued prior to late 1941.

There is some dispute if supercharges were ever issued to warships which had 30* gun elevation such as Vanguard. Some say yes and some say no. Normally the max range of the Vanguard's guns was 32,800 yards or ~30,000 meters according to R&R. That was using the standard charges and the 6crh wind screen shell. One source online lists the range as 33,600 yards with supercharges, so if correct it would hardly be worthwhile.

Maximum new gun range for the 15in/42 and supercharges (2638fps), using 6CRH ammo, was 37,830 yds. Naval Weapons of WW2.

dunmunro wrote:Maximum new gun range for the 15in/42 and supercharges (2638fps), using 6CRH ammo, was 37,830 yds. Naval Weapons of WW2.

That's 34-35km, not bad.
Any info about the accuracy of fire with supercharges ? Were the salvos consistent and shots well grouped ?

alecsandros wrote:

dunmunro wrote:Maximum new gun range for the 15in/42 and supercharges (2638fps), using 6CRH ammo, was 37,830 yds. Naval Weapons of WW2.

That's 34-35km, not bad.
Any info about the accuracy of fire with supercharges ? Were the salvos consistent and shots well grouped ?

I have no idea. I'm sure the info resides somewhere in the UK archives, and/or in test reports of supercharges used in coast defence guns.

Did Vanguard have more protected volume than Bismarck?
I always thought the Bismarck class were top in this respect.
And were the British following the German paradigm in that by designing Vanguard as they did?

spicmart wrote: Did Vanguard have more protected volume than Bismarck?
I always thought the Bismarck class were top in this respect.
And were the British following the German paradigm in that by designing Vanguard as they did?

KGV and Vanguard carried their main armoured deck one deck higher than on Bismarck, so their protected volume was greater than in Bismarck. I'm not sure what you mean by your last sentence, but Vanguard was an enlarged KGV design.

dunmunro wrote:

spicmart wrote: Did Vanguard have more protected volume than Bismarck?
I always thought the Bismarck class were top in this respect.
And were the British following the German paradigm in that by designing Vanguard as they did?

KGV and Vanguard carried their main armoured deck one deck higher than on Bismarck, so their protected volume was greater than in Bismarck. I'm not sure what you mean by your last sentence, but Vanguard was an enlarged KGV design.

I thought Bismarck had over 70 % of her length protected while KGV had only 55 %. I was wondering how much more Vanguard had.
And reading that Vanguard had more protected volume than every other BB made me assume that she should have at least as much length protected as Bismarck, this extended protection being a common feature in German BB philosophy.
Or did I just mistook protected volume with protected length?

spicmart wrote:

dunmunro wrote:

spicmart wrote: Did Vanguard have more protected volume than Bismarck?
I always thought the Bismarck class were top in this respect.
And were the British following the German paradigm in that by designing Vanguard as they did?

KGV and Vanguard carried their main armoured deck one deck higher than on Bismarck, so their protected volume was greater than in Bismarck. I'm not sure what you mean by your last sentence, but Vanguard was an enlarged KGV design.

I thought Bismarck had over 70 % of her length protected while KGV had only 55 %. I was wondering how much more Vanguard had.
And reading that Vanguard had more protected volume than every other BB made me assume that she should have at least as much length protected as Bismarck, this extended protection being a common feature in German BB philosophy.
Or did I just mistook protected volume with protected length?

Protected volume is not the same as protected length. Protected volume is the area protected by the armoured box (the citadel) formed by the main armoured deck and the main belt armour, and the fore and aft main armoured bulkheads. See this drawing for more info:

https://upload.wikimedia.org/wikipedia/ ... ection.png

KGV had belt extensions fore and aft of her citadel and thus had a protected length of about 68%, but this is not her protected volume.

I think Vanguard had more protected volume of main citadel then Bismarck did,
because she had a deeper main belt. The protected length being roughly the same, a deeper belt would imply a larger "protected box volume"...

Hi all,
of course one thing is the protected length (or volume), another is the "level" of this protection.

I understand that KGV/Vanguard vertical protection was making them immune to Bismarck guns only at relatively long range, while Bismarck was immune to the British 15" up to very short range (if any short range would be enough to penetrate the belt/slope combination anyway). However, Bismarck would have been more vulnerable to (less probable) underwater hits, due to her limited belt height.


Bye, Alberto