Alternate ship designs: Bismarck

[Shadow Master]

Hey guys, just wanting to ask a couple of quick questions here.

For an ATL Bismarck class, could a 2 X 4-15" gun design have made a better ship that OTL 4 X 2-15" gun design? I know of the historical theory that made them go the route they did, as well as the historical fact that the theory was wrong (2 turrets disabled by 1 hit, from HMS Rodney, IIRC), but what changes would result from my posited redistribution of main armament?

Specifically, what impact on the ships machinery spaces, if any? And what impact on the Armor layout?

Thanks.

Below are some interesting links that members have contributed to the discussion in thread. Enjoy.

I find this Navweps discussion thread (click here for link) to be extremely helpful when judging the merits of quadruple turrets.

http://www.navweaps.com/index_tech/tech-038.htm for Pros and Cons

Turbo Electric Drive 101

Check this out--very useful! German ship design: http://navweaps.com/index_tech/tech-044.htm and general naval technical data: Navweaps.com

Why the Nazi navy was so bad 101. I think that this should be required reading.

Start with a D-class cruiser layout, change to 2 x triple 15" guns. https://en.wikipedia.org/wiki/D-class_cruiser_(Germany) Include diesels for range, turbines for speed.

The D class cruiser design, as bad as the Alaska class?

Although NOT a link to outside content, I feel that this deserves a place here, on the OP, as well:

I have no specific sources for this so this is all my own feelings on the issue...

IMHO, a very well explained post.

There's a great article on ship desgn HERE: http://navweaps.com/index_tech/tech-035.htm

More good shipdesign information here.

Yet another good, information packed post, mainly dealing with AA guns. Here. Or Here, or Here

 

[Shadow Master]

Looking at some contemporary BB of the day, the Jean Bart class had a beam of just 108 feet, compared to the OTL Bismarck's 118 feet, while the KGV class had a beam of just 103 feet. Would this ATL Bismarck have had a weight savings over the OTL ship? Or would the two opposing layouts have come out the same in total tonnage for the turrets and their support structure?

 

[trurle]

I remember several ships of the era had an ergonomics problems with the 3-barrels and 4-barrels turrets. Inner barrels had too small workspace for loading. Also, may be severe problems with the availability of the motors and bearings to rotate heavier turrets at decent rate.

Overall, defence of 2-turrets Bismark will be improved a bit, but it may be offset by reduced fire rate and turn rate. Also, point-loading the ship frame will require stronger or more stressed frame, either negating defence improvement or increasing likelihood of catastrophic hull failure (ship breaking in two) after battle damage.

 

[Tonrich]

Even 3 X 3-15" would have been interesting.

 

[Shadow Master]

I remember several ships of the era had an ergonomics problems with the 3-barrels and 4-barrels turrets. Inner barrels had too small workspace for loading. Also, may be severe problems with the availability of the motors and bearings to rotate heavier turrets at decent rate.

Overall, defence of 2-turrets Bismark will be improved a bit, but it may be offset by reduced fire rate and turn rate. Also, point-loading the ship frame will require stronger or more stressed frame, either negating defence improvement or increasing likelihood of catastrophic hull failure (ship breaking in two) after battle damage.

I had not considered the latter points, so thanks for the heads up and good information. The former points, I knew about, but, other than building a slightly more roomy (wider) turret, what is there to do? I would want to make sure that a quad turret had not problems with 4 gun crews woeking at once, so no reduction in rate of fire and such would have to be studied carefully. I wonder what the avaliability of the machinery was for the OTL turrets? Were they 'off the shelf' components, or purpose built?

 

[Shadow Master]

Even 3 X 3-15" would have been interesting.

Yep. I thought of that, but I wanted to make an extreme difference as much as possible from OTL, and 3 X 3 would still have more turrets, and thus more machinery, and a thinner armor scheme streched over their length. OTOH, it does give an extra 15" gun. Interesting.

 

[AJE]

It would have been much smaller, for a start, the Richelieu could pretty much match the Bismarck in effectiveness with significantly less displacement, and it used the same layout you suggest. Other than that, the effectiveness depends on how well the other problems with such a turret were solved. In the case of the Richelieu, the French never could quite figure out how to deal with shell dispersion issues arising from such closely spaced guns. However, the US simply delayed the center guns on the Nevada class to fire a fraction of a second after the other 2, and this solved the problem for them. Another design feature would be that the Germans would have to put the guns closer together, making each gun have to elevate with its pair, rather than have 2 independently elevating guns, because the width of a true 4-gun turret would be too great. This was the case on Dunkerque and Richelieu. Despite this, the problems shouldn't be too great an issue, as they are either trivial to solve or only affect rare combat situations (like trying to fight multiple enemy ships simultaneously- historically this almost never happened, the ship would focus on one ship at a time), and it would save a lot of steel or produce a much better ship than OTL.

 

[trurle]

I had not considered the latter points, so thanks for the heads up and good information. The former points, I knew about, but, other than building a slightly more roomy (wider) turret, what is there to do? I would want to make sure that a quad turret had not problems with 4 gun crews woeking at once, so no reduction in rate of fire and such would have to be studied carefully. I wonder what the availability of the machinery was for the OTL turrets? Were they 'off the shelf' components, or purpose built?

The machinery for large turrets was purpose-built, at least for anything larger than destroyers. I remember the Russian magazine of the era boasting "largest ever roller bearings" built specifically for heavy gun turret.

 

[Shadow Master]

It would have been much smaller, for a start, the Richelieu could pretty much match the Bismarck in effectiveness with significantly less displacement, and it used the same layout you suggest. Other than that, the effectiveness depends on how well the other problems with such a turret were solved. In the case of the Richelieu, the French never could quite figure out how to deal with shell dispersion issues arising from such closely spaced guns. However, the US simply delayed the center guns on the Nevada class to fire a fraction of a second after the other 2, and this solved the problem for them. Another design feature would be that the Germans would have to put the guns closer together, making each gun have to elevate with its pair, rather than have 2 independently elevating guns, because the width of a true 4-gun turret would be too great. This was the case on Dunkerque and Richelieu. Despite this, the problems shouldn't be too great an issue, as they are either trivial to solve or only affect rare combat situations (like trying to fight multiple enemy ships simultaneously- historically this almost never happened, the ship would focus on one ship at a time), and it would save a lot of steel or produce a much better ship than OTL.

Interesting comparisons here.

Jean Bart: 30 kts, 8 15" guns in a pair of forward quad turrets.
Length: 813 ft
Beam: 108 ft
Draft: 32 ft

Bismarck: 30 kts, 8 15" guns in 4 twin turrets, 2 fore and 2 aft.
Length: 793 ft
Beam: 118 ft
Draft: 31 ft

KGV: 28 kts, 10 14" guns in 3 turrets, 2 quad (1 fore and aft), and one twin fore.
Length: 745 ft
Beam: 103 ft
Draught: 33 ft

My ATL ship;
Bismarck: 30 kts, 8 15" guns in 2 quad turrets, one fore and one aft (Or perhaps both aft?)
Length: 793 ft
Beam: 118 ft
Draft: 31 ft

When I first read about the Nelson class, I wondered if anyone had ever built the opposite lay-out, with all main guns aft, so that you could fire all your main guns at a persuing Nelson class ship, while they chased you.

Would an "all in the stern" layout create problems? What about the Deutschland class, could they have been built with this design configuration? Seems like it couldn't hurt if they were forced to flee enemy warships, and only a very fast merchant ship could try to take advantage of this armament layout scheme.

 

[AJE]

Interesting comparisons here.

Jean Bart: 30 kts, 8 15" guns in a pair of forward quad turrets.
Length: 813 ft
Beam: 108 ft
Draft: 32 ft

Bismark: 30 kts, 8 15" guns in 4 twin turrets, 2 fore and 2 aft.
Length: 793 ft
Beam: 118 ft
Draft: 31 ft

KGV: 28 kts, 10 14" guns in 3 turrets, 2 quad (1 fore and aft), and one twin fore.
Length: 745 ft
Beam: 103 ft
Draught: 33 ft

My ATL ship;
Bismark: 30 kts, 8 15" guns in 2 quad turrets, one fore and one aft (Or perhaps both aft?)
Length: 793 ft
Beam: 118 ft
Draft: 31 ft

When I first read about the Nelson class, I wondered if anyone had ever built the opposite lay-out, with all main guns aft, so that you could fire all your main guns at a persuing Nelson class ship, while they chased you.

Would an "all in the stern" layout create problems? What about the Deutschland class, could they have been built with this design configuration? Seems like it couldn't hurt if they were forced to flee enemy warships, and only a very fast merchant ship could try to take advantage of this armament layout scheme.

The last Richelieu-class battleship, Gascogne, was in fact planned to be a redesigned variant with one turret fore and one aft, much like the Deutschland. However, this meant the armored citadel had to extend all the way from the front turret to the back (instead of just covering 2 turrets in the front), and she would have been much heavier or less-protected than her sisters.

I'm not sure about an all-aft configuration of armament, I would assume that arrangement is only useful in niche scenarios, and for the vast majority of engagements an all-forward or a balanced layout would be superior.

 

[Shadow Master]

The last Richelieu-class battleship, Gascogne, was in fact planned to be a redesigned variant with one turret fore and one aft, much like the Deutschland. However, this meant the armored citadel had to extend all the way from the front turret to the back (instead of just covering 2 turrets in the front), and she would have been much heavier or less-protected than her sisters.

I'm not sure about an all-aft configuration of armament, I would assume that arrangement is only useful in niche scenarios, and for the vast majority of engagements an all-forward or a balanced layout would be superior.

Oh, I agree, most ships would probably benifit from a standard layout, but what about, in the specific case of a commerce raider design, where by intent, you need to run from enemy warships?

 

[marathag]

Turret weight

Yamato 2774 tons
Richelieu 2476 metric tons
Littorio Triple 1592 metric tons
RN Mk III Quad 1582 tons
RN Nelson 1483 tons
Nagato 1287
North Carolina triple 1220 tons
Bismarck twin 1056 metric tons
Alaska triple 930
Colorado twin 920 tons
RN Mk II twin turret 915 tons
Scharnhorst 750
Arizona triple 724

Note: some US weights are 'revolving weight' less that overall weight of the others, not including shell room weight, for example, Arizona vs Alaska weight

 

[Shadow Master]

Turret weight

Note: some US weights are 'revolving weight' less that overall weight of the others, not including shell room weight, for example, Arizona vs Alaska weight

Thats some good information to have, where on earth did you unearth all of that? So, the OTL Bismarck turrets weighed in at 1,056 tons each, for a twin 15" armament, so if I wanted to have a quad (I have heard that the Richelieu were paired twin), then I would be looking at something less than 2112 tons total, so lighter than either the Richelieu or Yamato turrets, but considerably more than those on the KGV. Looking at that some more, it seems odd that the German turrets, with 4 15" guns, would be 1.5 times heavier than the RN turrets with 4 14" guns.

How much of the weight of a turret would be in one sides armor? In other words, if I basically took the sides off one turret, and placed that in the middile of another turret, would that give me a ball park figure for weight wavings?

Also, if one fore and aft, rather than two fore and aft, turrets are fitted, can I double the armor thickness there, or is their more to it than that?

 

[AJE]

Thats some good information to have, where on earth did you unearth all of that? So, the OTL Bismark turrets weighed in at 1,056 tons each, for a twin 15" armament, so if I wanted to have a quad (I have heard that the Richelieu were paired twin), then I would be looking at something less than 2112 tons total, so lighter than either the Richelieu or Yamato turrets, but considerably more than those on the KGV. Looking at that some more, it seems odd that the German turrets, with 4 15" guns, would be 1.5 times heavier than the RN turrets with 4 14" guns.

How much of the weight of a turret would be in one sides armor? In other words, if I basically took the sides off one turret, and placed that in the middile of another turret, would that give me a ball park figure for weight wavings?

Also, if one fore and aft, rather than two fore and aft, turrets are fitted, can I double the armor thickness there, or is their more to it than that?

I find this Navweps discussion thread (click here for link) to be extremely helpful when judging the merits of quadruple turrets. Personally, I prefer them over triple turrets, because while they may actually weigh more in terms of turret weight per gun, their advantage of less barbettes required stiffens the ship and shortens its armored citadel considerably, more than making up for the extra turret weight.

 

[marathag]

Thats some good information to have, where on earth did you unearth all of that?

Just data I squirreled away from years on Usenet and other WWW sites over the years.

Steel weighs around 490 pounds a square foot, depending on the exact alloy. How much more you want?

West Virginia gained an extra 7.5" on the turret tops for an extra 38 tons during her post PH rebuild

 

[MattII]

IMO the turrets were much less of an issue than the propulsion. Triple-shafts was a damned stupid idea, as the centre shaft interrupts the keel, and provides jack all in terms of engine turning, which was the primary reason she bit it.

 

[CV12Hornet]

There are also improvements to be made to the armor scheme. The turtle-deck layout should be left alone, as the designers did have an appropriate rationale for it, but the upper and end belts should have been deleted, which frees up weight for other areas.

 

[Gunnarnz]

Steel weighs around 490 pounds a square foot, depending on the exact alloy. How much more you want?

Shouldn't that be cubic foot? Or are we talking a certain specific thickness of steel here?

 

[Shadow Master]

Just data I squirreled away from years on Usenet and other WWW sites over the years.

Steel weighs around 490 pounds a square foot, depending on the exact alloy. How much more you want?

West Virginia gained an extra 7.5" on the turret tops for an extra 38 tons during her post PH rebuild

Wow! You may be one of the folks that might be able to help me finally understand springsharp! I have a great many questions about that software, like at least as many as the software has, and then some. I couldn't make use of springsharp as I had no clue what all the questions it was asking me were, let alone what kind of input they needed.

2 basic questions for right now, on my posited ATL Bismarck;
1) Do Quad turrets, if optomized for maintaining ROF, offer good things for armor redistribution?
2) If instead of one fore and aft quad, they decided to go all in, and place both turrets in the stern, is that doable/better?

My concers here are that in a stern chase, the Bismarck is able to run away at full speed, and bring every main battery gun to bear, until they are overtaken, or escape, but I don't want them to cripple their design by messing with the ships machinery/speed.

 

[Shadow Master]

IMO the turrets were much less of an issue than the propulsion. Triple-shafts was a damned stupid idea, as the centre shaft interrupts the keel, and provides jack all in terms of engine turning, which was the primary reason she bit it.

So, 2 or 4 shafts?