AHC: improved Deutschland-class cruisers.

Scharnhorst preceded Bismarcks for a reason, nothing near that size had been built in Germany since WWI

A.G. Wesser at Bremen did the 55,000 ton Liners Bremen and Europa in the '20s.

Keil, Bremen, Wilhelmshaven and Hamburg all had shipyards that could have built the large warships, but until Treaty [of Versailles was tossed, they could only do liners and cruisers under 10,000 tons

They could have started with Bismarck. It was political limits, not physical when Gneisenau was ordered in 1934 and Bismarck in 1936, as allowed by the Anglo-German Naval Agreement on 1935.
The Royal Navy thought a German Fleet with Battleships would be far less threatening to the UK than the allowed tonnage of Panzerschiffe, UBoats and Heavy cruisers would present
 
A.G. Wesser at Bremen did the 55,000 ton Liners Bremen and Europa in the '20s.

Keil, Bremen, Wilhelmshaven and Hamburg all had shipyards that could have built the large warships, but until Treaty [of Versailles was tossed, they could only do liners and cruisers under 10,000 tons

They could have started with Bismarck. It was political limits, not physical when Gneisenau was ordered in 1934 and Bismarck in 1936, as allowed by the Anglo-German Naval Agreement on 1935.
The Royal Navy thought a German Fleet with Battleships would be far less threatening to the UK than the allowed tonnage of Panzerschiffe, UBoats and Heavy cruisers would present
Correction no large warships that size. There is a lot of difference between warships and civilian ships

They wanted 15" guns with Scharnhorst, but that would delay matters as the turret design for 15" would take years, whereas they had a perfectly good 11" design they could modify. Likewise it takes time to do things like expand rolling mills for armor or gun pits, plus you want to give your designers and builders experience on something smaller
 
But if you really look at Bismarck, it's a rehash of late HSF Battlecruiser designs
SMS_Ersatz-Yorck-linedrw_top-and-side_b.gif

like the 38,000 ton SMS Ersatz Yorck, laid down in 1916 at Hamburg
This class were scrapped incomplete. Krupp wasn't forbidden from making thick plate in the interwar period, and all facilities were intact, but mostly idle. These were dual purpose yards, that were getting by from making civilian ships in the '20s
 
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Correction no large warships that size. There is a lot of difference between warships and civilian ships

They wanted 15" guns with Scharnhorst, but that would delay matters as the turret design for 15" would take years, whereas they had a perfectly good 11" design they could modify. Likewise it takes time to do things like expand rolling mills for armor or gun pits, plus you want to give your designers and builders experience on something smaller

German sources I read state that Scharnhorst design was designed for 9*11" guns then 8-9* 13" guns and finally 6*14" guns but Hitler rejected all this and forced them to return to the 11" gun design. So Raeder had them build each turret so it could handle 3 * 11"C34 guns and later rearmed with 2* 14" guns later. All this was 1933/34 and Krupp decided to go ahead and build 15" & 16" guns even though no such guns were planned for . As was pointed out many yards built civilian ships because it paid the bills until military contracts were renewed.
 
Converting the Deutschland Battleships into budget Panzerships would cost about as much as just building a new ship the same size, or even more. To get any real increase in speed you would need to alter the hullform, optimized for 18.5 knots, otherwise most of the extra power you add will be wasted, and being able to outrun even the slow British and US battleships would be unlikely

Getting the speed to keep up with even a Capital ship with a supply ship pretty much requires a capital ship sized machinery plant, and that sort of machinery is specialist stuff, could very well slow down completion of capital ships and would massively increase costs, plus would require a hullform poorly optimized for carrying supplies

The best use of the old pre-dreads the DKM got from the HSF was to either use them as they did (they were valuable auxiliary vessels) or to use them to support Baltic operations with NGFS missions, possibly extra Flak,etc etc. Converting them into anything requiring more speed is simply uneconomical.

Yes I agree keep them as auxiliary they had 5 still in the mid 1930s, but I would still risk them to spearhead invasions as armored troop transports - like into Norway.

remember they converted one, adding 10m (to alter hull form) and added geared turbines (25,000 SHP) to reach 20 knts. http://german-navy.de/kriegsmarine/ships/misc/hessen/tech.html from a layman's POV was thinking the diesel arrangement in Bremse (26,000 SHP) would suffice? (and that greater than 10m could be added if productive?)

the type of missions mentioned were exactly the intention, also mentioned keeping the PBs in home waters.
 
That would be a waste, not using the ships greatest strength, long cruising range and matching crew accommodations if you never plan to leave the North Sea or Baltic

it would also make great ship in home waters with sustained operations, something their DDs and LCs were not able to perform, of course this is against a backdrop of larger numbers of auxiliary cruisers (the expendables.)
 
But if you really look at Bismarck, it's a rehash of late HSF Battlecruiser designs

like the 38,000 ton SMS Ersatz Yorck, laid down in 1916 at Hamburg
This class were scrapped incomplete. Krupp wasn't forbidden from making thick plate in the interwar period, and all facilities were intact, but mostly idle. These were dual purpose yards, that were getting by from making civilian ships in the '20s
The human factor is the biggest issue--there haven't been junior officers going through the naval engineering pipeline designing and constructing battleships for the past 20 years, and it takes at least a couple of years if not a decade to rebuild that institutional knowledge. Sure, you could call up the old veterans, but even their knowledge would be rusty, not to mention 20 years out of date.
 
remember they converted one, adding 10m (to alter hull form) and added geared turbines (25,000 SHP) to reach 20 knts. http://german-navy.de/kriegsmarine/ships/misc/hessen/tech.html from a layman's POV was thinking the diesel arrangement in Bremse (26,000 SHP) would suffice? (and that greater than 10m could be added if productive?)

the type of missions mentioned were exactly the intention, also mentioned keeping the PBs in home waters.
Well, with this inspiration and remarking that the ships were intended as an anti-Versailles provocation: buil a short clumsy ship at 12000 tons with 3x2 13-15 inch whatever is possible designed for inserting a 6000 tons midsection later. Or better, make it and be sure the bolts are visible on the first ships.
 

NoMommsen

Donor
... with 3x2 13-15 inch whatever is possible ...
Due to "informal" questioning in the mid twenties, it was made clear to the germans, that anything about 28 cm was NOT acceptable.

As for the Hessen and its conversion to a radio guided target ship :
"Only" a ney bow was added, the stern remained unchanged. Some "addition" here might have further "improved" speed above the 20,3 kn it reached with the installed ~ 25000 bhp.
According to the "Gröner" the Hessen standard weight after the conversion was 12200 t, without any armament and very reduced structures but ... Gröner unfortunatly does NOT state was changes were made to the armor, which was definitly "upgraded" for its purpose.
 
but even their knowledge would be rusty, not to mention 20 years out of date.

But as I pointed out, much of the new KM was 20 years out of date, new on the launching slips. Besides the Battleships, Graf Zeppelin was filled with design flaws that the USN, IJN and RN had discovered in the '20s

Other than Operating Depth, the VII class U-Boats were hardly as good as the US WWI era S-Boats
 
Well, with this inspiration and remarking that the ships were intended as an anti-Versailles provocation: buil a short clumsy ship at 12000 tons with 3x2 13-15 inch whatever is possible designed for inserting a 6000 tons midsection later. Or better, make it and be sure the bolts are visible on the first ships.

One thing I neglected to mention about a redesigned 15,000 tonne Deutsshland/Lutzow is the need to frame the hull to take the shock of operating a larger bore battery over length.

"a short clumsy ship at 12000 tons with 3x2 13-15 inch" is bound to give me heartburn when I think about hull stress and sea worthyness. Are the German designers restricted to the kind of yaw/rollers the US designers came up with to fight the Spaniards or the waffle irons Togo so happily sunk at Tsushima? Those were not good ships. Topheavy auto-sinkees is what the Russians named them.

But as I pointed out, much of the new KM was 20 years out of date, new on the launching slips. Besides the Battleships, Graf Zeppelin was filled with design flaws that the USN, IJN and RN had discovered in the '20s

Other than Operating Depth, the VII class U-Boats were hardly as good as the US WWI era S-Boats

"the VII class U-Boats were hardly as good as the US WWI era S-Boats"

Aside from:

a. better air scrubbers.
b. hydrophones.
c. periscopes.
c. marine diesels
d. battery arrangements.
e. torpedo handling equipment.
f. depth control arrangements
g. radios
h. crew sleeping arrangements.
i. pressure hull assembly methods.

the Type VIIs were hardly as good as the US interwar era S boats.

The only area where the S-boats might have had a slight edge was in the Mark 10 torpedo. It worked halfway decently better than the early G=7s until the Germans fixed their fish in 1941.
 
The only area where the S-boats might have had a slight edge was in the Mark 10 torpedo. It worked halfway decently better than the early G=7s until the Germans fixed their fish in 1941.

VIIA 1935
626 tons displaced surfaced
Length: 211'
Beam: 19'3"
2310HP 17 knots surfaced, 8 knots submerged 720 ft max depth
four forward tubes, one stern. 11 carried
88mmL45 deck gun
6,200 nmi at 10kn
44 crew

S Boat, 2nd group 1918
890 tons displaced surfaced
Length: 231'
Beam: 21'6"
2000HP 15 knots surfaced, 10.5 knots submerged 300 ft depth
Four Forward tubes 14 carried
4"L50 deck gun
5,000 nmi at 10 kn
38 crew
Since the U-Boat is smaller, hard to see how they had better crew space with more crew than the S-Boat, and the KM, unlike the USN, didn't have laws set by congress on living spaces.
 
Well this is a complex subject...how much time do we have?

I mulled over this and could not make either option work [21 PBS VS 375 U-Boats]...but I still got a damn sight better fleet than historical.

Thought experiment.

As mentioned the KM laid down 21-23 large warships in the prewar Hitler years ,but they also laid down over 200 smaller vessels many of which were costal vessels, however all where diesel/bunker oil. In WW-I such ships were always laid down as coal powered, since German coal supply was order of magnitude better/more secure than diesel or bunker oil. Roughly speaking 1/4 to 1/3 million tons diesel every year was consumed by coastal forces. It was a strategic mistake using diesel engines and fuel this way.

Step 1. for heavy ships.

Step 2. for FACs and torpedo boats.

Step 3. Engines for FACs.

Step 4. Engines for large warships.

The German diesel industry might have managed to build enough large diesels for 21-23 big warships, especially if they can switch over to the advanced diesels [late 30s] instead of high pressure/temp boiler-turbines. A 14,000 ton [max] PBC about the size of the AGS- with completed hull form & transom stern, could be built through the 1930s , with 10 completed before war and 3 more early 1940s.

Brief discussion.

The idea of unit machinery lends itself to certain interesting marine engineering solutions. My own thoughts on this subject here are heavily influenced by American turbo-electric machinery of the 1920s, but read me out. Consider a baseline 5000 kW diesel/electric generator set. that is about ideal for a submarine if one can build it. The same motor/generator set can be ganged up in a configuration to supply power to surface ship electric motor final drives. No backing engines. No specialized turbine sets for destroyers, cruisers, or battleships. Specialized electric motor final drives per shaft (4,700 kW, 9,400 kW, 18,800kW) but one gets the point? Downside is that all these power plants arrangements (1 motor/generator final drive, 2 motor/generator/final drive, 3 motor/generator/final drive,) can result in diesel powered cruisers and battleships as well as subs. All of these types will be noisy. The three classes should be long-ranged and most definitely (except for subs) fuel economical.

Top speed should be 30 knots standard & 28 knots deep. The armor should be 3000 tons and offer estimated 6-7" belts plus 3" deck [all multiple plates ]. The armament should include 2 triple 11"C28 gun turrets [although 6 of these 20 turrets would have to be removed from the Deutschland class to keep production going ] . In addition 24 torpedoes in 4 triple mounts would also be mounted along the side superstructure. In between those should be 4 twin 4" flak; although most would start off with twin 88 flak turrets and all swap out with 6 twin 4"flak , a couple of years into war.

If we are after cruiser/raiders then we are in disagreement. The sustained speed in a seaway is critical. Armament is also a disagreement. C-28 guns with a long-rod ACR base fuse shell designed is acceptable, but 4x2 is my preferred. (See above previous for why.). Torpedo battery, given the time period is also problematic. The torpedoes available to the KM are worse than the US Mark 11s!
Based on tech, no more than a pair of quad H-8s and that more for psychology than for effectiveness. Armor is either all or nothing. 20 cm belt will be swiss cheesed by contemporary US or UK 8 inch guns at effective battle ranges (4-15 km), so nothing. Put the tonnage into sustained speed. I agree with a 8 cm deck. Bombs and plunging shells have to be stopped so the raider has a chance to flee. A turtle deck (protected cruiser) scheme may be appropriate.

Along side the PBC program , about 11 larger heavier Panzerschiffe would be completed [6 before 1940 & 5 finished 1940 -1942] . These should be Scharnhorst size @ 27,000 tons max with 6000 tons armor offering 4" deck & 12" belts. The main batteries would initially be either 3 triple 11"C28 or 3 twin 12"SKL 50 [WW-I guns used as coastal batteries in WW-II]. The Panzerschiffe completed from 1940 on- should be armed with twin 13" gun turrets , and all previous Panzerschiffe should be up gunned to the same 3 twin 13" guns standard by 1942/43. Each of these warship should be also armed with 8 twin 4"flak from the start plus 2 dozen torpedoes.

That works out to 35,000 tonnes. Better opt for 38 cm/45 (14.96") SK L/45 (3x2/3 twin mounts). These are known quantities and Krupp knows how to build them in 1927. NO TORPEDOES! More Flak. See my comments above; especially about Wurzburg organs and 10.5 cm twins. Germany can build 4 or maybe 5 before 1940. No more than these. Not enough slips, not enough time, not enough resources.
 
One thing I neglected to mention about a redesigned 15,000 tonne Deutsshland/Lutzow is the need to frame the hull to take the shock of operating a larger bore battery over length.

"a short clumsy ship at 12000 tons with 3x2 13-15 inch" is bound to give me heartburn when I think about hull stress and sea worthyness. Are the German designers restricted to the kind of yaw/rollers the US designers came up with to fight the Spaniards or the waffle irons Togo so happily sunk at Tsushima? Those were not good ships. Topheavy auto-sinkees is what the Russians named them.

1.
Maybe you are spot on,
Maybe not. Just need to be clear. What I intend is to design a 17000 tons ship on paper, take away the midsection, and put on the gear possible to make it float.
Then build the real ships later.
Not going to work?
 
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VIIA 1935
626 tons displaced surfaced
Length: 211'
Beam: 19'3"
2310HP 17 knots surfaced, 8 knots submerged 720 ft max depth
four forward tubes, one stern. 11 carried
88mmL45 deck gun
6,200 nmi at 10kn
44 crew

S Boat, 2nd group 1918
890 tons displaced surfaced
Length: 231'
Beam: 21'6"
2000HP 15 knots surfaced, 10.5 knots submerged 300 ft depth
Four Forward tubes 14 carried
4"L50 deck gun
5,000 nmi at 10 kn
38 crew
Since the U-Boat is smaller, hard to see how they had better crew space with more crew than the S-Boat, and the KM, unlike the USN, didn't have laws set by congress on living spaces.

if one looks here: and here: one gets a better idea of what I discuss.
 
Maybe you are spot on,
Maybe not. What I intend is to design a 17000 tons ship on paper, take away the midsection, and put on the gear possible to make it float.
The build the real ships later.

Pass throughs, piping, ventilation, electrical, fire mains, keel, etc. This is the 1920s/30s. Nobody knows about Kaiser modules yet, not even Henry Kaiser.
 
Pass throughs, piping, ventilation, electrical, fire mains, keel, etc. This is the 1920s/30s. Nobody knows about Kaiser modules yet, not even Henry Kaiser.
Well, we are talking about the same thing. The Kaiser modules worked (not so well on the electroboote), and both were invented to serve a specific need. If a decision os made to make a ship for later upgrade, why not?
 
Well, we are talking about the same thing. The Kaiser modules worked (not so well on the electroboote), and both were invented to serve a specific need. If a decision is made to make a ship for later upgrade, why not?

Not so well in the Liberty ships either.

Not arguing against it, but these are instructive; expensive, took years and wasted scarce resources. Module ships also have unforeseen outcomes. The US tried something like it with her WW II oil tanker to CV conversions (insert a spacer to lengthen the T-3 hull; no tank testing?) and screwed up the pitch moment to coincide with the crest trough moment of a Pacific swell. Not too good for carrier ops.
 
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