WesWorld

I've still no idea what bulge you are talking about.

Belt is 4.86m with the inclusion of the lower portion. The newer French BBs have 3.70m and 3.60m deep belts respectively. Its better than the historical Littorio because of the lower belt armour which deepens the belt significantly. The USN fast BBs had only 3.1m deep belts.

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Wasn't Krupp moved out of country post 1918? In which time period their shells would have been available on the open market, no?

Presuming Jutland occurred as historical, many countries would have been desirous of examining German shells.

As far as I can tell, no, Krupp didn't move out of country during the Weimar period, they diversified into other non-military markets. And, even if you cross-section a projectile, the differences are not obvious. As far as is known now, the only real difference was in the type of solder used to bond the cap to the shell. See Nathan Okun's article for more details: http://www.navweaps.com/index_tech/tech-085.htm

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Originally posted by Red Admiral
I've still no idea what bulge you are talking about.

Belt is 4.86m with the inclusion of the lower portion. The newer French BBs have 3.70m and 3.60m deep belts respectively. Its better than the historical Littorio because of the lower belt armour which deepens the belt significantly. The USN fast BBs had only 3.1m deep belts.

The blue bulge on the tower foremast in the third view from the top.

The lower portion is, by defniition, below the waterline. When I was putting up designs for proposed German ships of the same size, one of your criticisms was that the belt was too short, at 3.75m.

Shouldn´t BB pic reflect such design features like a transome?

The bulge is just to give the main director a bit more room to turn in.

See here.

Yes deeper is better. I could make the main belt a bit taller to 4.50m without changing much else. Isn't that much weight. However because it is external and inclined there are problems with mounting it. I think about 4.0-4.50 is probably the limit for this. Littorio's 4.10m belt has a pronounced step to it and juts out considerably.

I call it artistic licence Stephan...

...and you all knock on Canada's 5.5" DP guns. -_-

Heh, I'm knocking on these, too! I'm an equal opportunity knocker!

Rate of fire in the AA role is the main problem. I looked into it with lots of examples from navweaps to try and see a trend. 12rpm sustained should be possible with shells around 35-40kg. Absolute maximum until ready-use ammunition is used up (or crew breaks) is about 18-19rpm.

A quote from RA, back on the 16th of August of last year, in the discussions on proposed Canadian DDLs armed with DP 5.5" guns:

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Originally posted by Red Admiral
5.5" are really too large to manually load for long periods of time. Until 1940ish with the RP10 mounting you seriously limit the rate of fire.

And this won't be even more true of 6" rounds?


The ONLY historically useful DP 6" guns were the various (Swedish, British, US) post-war autoloaders. The attempts before WWII were all limited by low rate of fire, inability to load at high angles, and inability to train and elevate rapidly enough. They could be used as AAA weapons, but they were not effective at it.

Guess I should ask what MDT shells are...

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And this won't be even more true of 6" rounds?

I was wrong before. Having looked into it more I changed my mind.

Problems:
Low rate of fire already addressed
Increased train/elevation rates: more powerful AC motors altogether weight increase of maybe a ton at most. AC motors as you can go for 2.5x overload on start up in order to get the heavier 152mm barrels moving.
Loading at high angles: Either set a lower loading angle (e.g. 20° for the 6"/47) or have a larger mechanism that moves with the gun.

MTF stands for Mechanical Time Fuse. They're what are used for AA. Essentially HE shells with clockwork fuses. I considered barometric fuses but they wouldn't be accurate enough. (needed 0.001% accuracy IIRC)

Another note on Vanguard's RP10 mounting. Navweaps has some incorrect information (well not consistant with Campbell or others) which states that the RP10 had automatic loading and an 18rpm rate of fire. This is probably incorrect. The turret is best described as "mechanised". It had remote power control (i.e. controlled from Director), increased rates of train and elevation, and a considerably larger and not cramped turret. The mechanised portion included an automatic rammer and power assist for moving the shells and cartridges around the turret. The breech is still hand worked and there are men moving projectiles in the turret.

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Originally posted by Red Admiral
I was wrong before. Having looked into it more I changed my mind.

In that case, I expect Canada's 5.5" DP project to be a smashing success. ¬_¬

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Originally posted by Hrolf Hakonson
A quote from RA, back on the 16th of August of last year, in the discussions on proposed Canadian DDLs armed with DP 5.5" guns:

Quoted

Originally posted by Red Admiral
5.5" are really too large to manually load for long periods of time. Until 1940ish with the RP10 mounting you seriously limit the rate of fire.

And this won't be even more true of 6" rounds?


The ONLY historically useful DP 6" guns were the various (Swedish, British, US) post-war autoloaders. The attempts before WWII were all limited by low rate of fire, inability to load at high angles, and inability to train and elevate rapidly enough. They could be used as AAA weapons, but they were not effective at it.

This eco's my thoughts too, I have my doubts about the 5.5" DP and Shinra's eluded to the fact they may turn out to be dud's.

If you look at Nathan Okun's article on time fuzed shells, http://www.navweaps.com/index_tech/tech-020.htm, you'll find that a varying rate of fire is absolutely a wonderful way to miss the target, as all the calculations assume a fixed time between when the fuze is set and when it is fired. Firing at a faster rate will mean the shell explodes too late, firing at a slower rate means the shell explodes too soon.

Having to load at a lower angle will decrease the rate of fire because the gun will have to elevate back to where it needs to be to fire the round. The US 6"/47 was faster at elevating than most of its contemporaries, at 10 degrees per second, but to fire at 45 degrees it would need to spend 2.5 or more seconds elevating before firing after loading and the same amount of time lowering after firing.

Loading at any angle is going to require fairly major mechanical machinery, which others have been simulating on smaller weapons by simming an additional gun in a twin turret or by using an equivalent amount of miscellaneous weight (for a future ship, Germany's used 400 tons for 6 twin 150mm turrets).

Sorry, Shin, that's about the only way that I can see that the 140mm is going to be a good AA weapon, and based on history you're probably looking at 1945 or later before it'll work right (see the problems the US had with the 6"/47 DP mounts).

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Originally posted by Red Admiral
Rate of fire in the AA role is the main problem. I looked into it with lots of examples from navweaps to try and see a trend. 12rpm sustained should be possible with shells around 35-40kg. Absolute maximum until ready-use ammunition is used up (or crew breaks) is about 18-19rpm.

This didn't fit with my recollection, so I went over to Navweaps also. Yes, mid 1930s weapons with shells in the 35-40kg range did 7 to 12rpm, with the Russian 130mm/50 DP making 13rpm.

I'm not what the basis is for the 18-19rpm, I did find a 18rpm "burst" such as you are talking about, but it was on the 4.5"/45 QF MkV, which entered service in 1947 with a 25kg shell. Other than that, you have a couple of period weapons with ROFs approaching that, but none are in the 6" range.

However all of these are also not 6" weapons, but rather smaller & lighter pieces in the 115mm-135mm range. So the analogy is not applicable unless you are intending a light AA shell.

You could make a light 6" shell, but wouldn't the reduced weight for the same cross section result in a more rapid loss in velocity vs. a smaller shell of the same weight? Meaning less effective, but you still pay all the additional weight and volume of the 6" mounting while having more mass to try to slew to track AA targets.


Oh Hrolf- my bad on Krupp, they bought part of Bofors and were involved in Sweden that way, I misremembered.

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I'm not what the basis is for the 18-19rpm, I did find a 18rpm "burst" such as you are talking about, but it was on the 4.5"/45 QF MkV, which entered service in 1947 with a 25kg shell. Other than that, you have a couple of period weapons with ROFs approaching that, but none are in the 6" range.

The US 6"/47 not DP version managed 15rpm onboard USS Helena for short periods of time. Similarly the Fixed rounds on Le Hardi of 53kg for the 130/45 could fire up to 15rpm. The German 127/61 twin with fixed 48kg round fires up to 20rpm.

Its definitely possible.

A 152mm HE shell is going to be lighter anyway as there is less metal. A more streamlined shell better suited to AA would decrease weight further.

Varying the rate of fire: hoists to supply shells/cartridges at 12 per minute per gun with higher rates of fire only being available from the ready-use ammunition in the turret (c.10rpg)

The previous Italian model 152/53 gun loaded at any angle and elevated to 45° (in OTL) with a couple of years development it wouldn't be hard to further increase the elevation angle to 70-80° the fact that the previous gun elevates to 45° indicates that the gun axis is already high enough and elevation could be increased further.

On account of the mounting weighing more I have allowed considerable misc. weight for this eventuality. However, please find me a link between weight and rate of fire or weight and elevation angle. There is no definite relationship between the two.

Yes, the 6"/47 managed burst rates higher than it's rated ROF at times for short periods when the target was at a range where the gun did not have to be elevated to fire and lowered after firing to reload and with a well-trained crew. That burst pace, as noted in Nathan Okun's article, would NOT be good for AA fire, as it would not be predicatable. Le Hardi's guns only elevated to +30 degrees, while the KM41 was exclusively (in service) a ground-mounted weapon that was usually deployed in open mountings where the crew had room to work.

In the description of the ship, there's no mention of the miscellaneous weight being dedicated to the 6" guns. Right now it's available for use for radar, more light AA, etc.

A higher elevation requires a deeper turret, so the breech doesn't hit the floor of the turret. That's especially true if you're going to load at any angle, since you have to have enough room below the breech to load and ram the projectiles For confirmation, look at the difference in weight between the 5"/38 Mk 22 twin SP mounting and the other 5"/38 twin DP mountings: the low angle only SP mounting is over 25% lighter than any of the DP mountings, which is why it was developed for use on the Porter class DDs (see http://www.navweaps.com/Weapons/WNUS_5-38_mk12.htm).

HE rounds might, or might not, be lighter than other rounds. Later US (the 6"/47) and Italian HE rounds in this size range seem to have been lighter than the corresponding AP rounds, German and British HE rounds were the same weight as their AP rounds. French HE rounds were in some cases heavier than their AP rounds.

In view of recent events, some of these ships might get built. Others might take their place. Probably only changes to the light stuff.

In other words all the ships will get built to the original treaty busting specs?