Atlantik bomber kreuzer

[Nick Sumner]

Over on this facebook discussion group

https://www.facebook.com/groups/208708329671558/
Someone named Stefan Bachi has posted the following drawings under the title ATLANTIKBOMBER-KREUZER and GROßER Atlantikbomber-Kreuzer. I find them, erm... surprising, just wondered if anyone knew more about them. They are apparently from the Marine Archive Freiburg.

 

[Nick Sumner]

There's also a design for an inflatable airfield apparently...

 

[ptdockyard]

Can we get a better read on the stats? Not clear in the drawing.

Dave

 

[Dilandu]

Er... Germans suggested building a specialized ship for one-way bomber operations?...

I never doubted that Nazi were rater dumb, but this is get to the point of being totally ridiculous...

 

[Jemiba]

To sum it up:
This is (according to the signature and the mark) a design from 1940, fora diesel powered light cruiser, which should be able
to accomodate up to eight twin engined bombers (Ju 88 ?) on the open deck, without hangar. Take-off and landing should be
possible on an inflatable raft, 200m x 20m, extended by a rollable mesh, 200m x 25m, which would have been rolled out by a
torpedo like float and was intended to dampen waves. I first thought, the aircraft were on catapults, but it rather seem to be
ramps for lowering them on that inflatable airfield. Additional to the four propellers, there seems to be a Voith-Schneider
propeller, too, maybe for better maneuverability during the process of launchinmg and recovering the aircraft ?
And no, it doesn't seem to be intended for one-way missions, because landing of aircraft ist explicitely mentioned.
But with such an accomodation, I can't think of much success bringing those aircraft further than into the North Sea during
very good weather !

 

[Grey Havoc]

Yes, this design does appear to have been intended for supporting amphibious invasions, with the aircraft landing at captured and/or improvised landing airstrips ashore. Though in practice, as Jemiba notes, it would have likely been restricted to operations in the North Sea/Danish Straits/Baltic Sea regions, though operations in the English Channel would have been theoretically possible.

 

[Hood]

I can't make up my mind if this is a fake or whether someone (engineer or well-intentioned amateur) in 1940 sketched out a crazy war winning idea and posted it to the Kreigsmarine and they politely thanked the inventor and put it safely into the archive to gather dust.

There are several features which betray this not being the work of marine architects.

The hull shape (bow and stern) looks quite weird.
Each propeller shaft looks to be driven by five 2,000hp diesel engines arrayed annularly around the shaft with the top-view indicating at least up to four or possibly five of these engine groups per shaft so the whole powerplant would be 80-100x diesel engines for 160-200,000hp for all four shafts!
The light AA (37mm?) on the forecastle is a poor placement. None of the gun mounts are particularly well sited or logically laid out. Likewise the aircraft are not well sited, that on the forecastle risks damage from spray in heavy seas and despite the use of superfiring position turrets, in reality using the main arrangement with the aircraft on the decks would lead to quite serious blast damage.

The aircraft doesn't look quite like a Ju 88. The cockpit and nose shape strongly remind me of another aircraft/project but frustratingly I can't recall its identity to mind (no its not the Fw 58 but that the area my thoughts were taking me).

To me this looks like the kind of armchair warrior ideas that made their appearance in magazines like Popular Mechanics and Illustrated London News on the Allied side (many of which have appeared in these forums). Well intentioned concepts that look radical but also highly flawed once you dig into them.

 

[DWG]

A detailed look at the little arrangement drawing for the combined set shows this is even more ambitious than a quick glance might lead you to think. It identifies the leading float as a "zugmaschine - lauft 6m unterwasser, geschlossene torpedoform" ie "tractor/tug, running 6m underwater, enclosed torpedo form" and that it's driven by electric motors powered from the ship. But it seems to say the float's engine power is only 300 ps - c295hp. What I initially thought was a triangular hullform is actually the towing cables running from the torpedo float to a spreader bar (presumably on the surface) that's trailing the net and then the strip, with the ship alongside the strip.

Now it is possible to do a side-by-side tow, I've actually done it on a yacht and manouverability was better than you'd expect, so the ship could propel the strip, with the torpedo float only responsible for keeping the net taut, but simultaneously coordinating a parallel tow and a lead tow from something running under the water, and operating aircraft on the combined ensemble has to be incredibly ambitious.

It might just be intended for holding position, rather than sailing into the wind - that would make the low power of the leading torpedo float make sense.

I do notice it specifically identifies the arrangement as "Wasser Rollfeld fur Flugzeuglandung auf dem Ozean", roughly "Water tarmac/airstrip for aircraft landing on the ocean", rather than say "Wasser Flugplatz fur dem Ozean" - "oceanic aerodrome", which makes me wonder if it is specifically a landing field. Because even with a 30 kt*+ headwind 200m is going to be fairly ambitious for a loaded bomber to take off. (And less if you stack aircraft at the tail end of the runway rather than transferring them one by one).

*I doubt they'd get more than 20kts out of the assembly assuming it is moveable, so that's including a headwind.

 

[DWG]

Each propeller shaft looks to be driven by five 2,000hp diesel engines arrayed annularly around the shaft with the top-view indicating at least up to four or possibly five of these engine groups per shaft so the whole powerplant would be 80-100x diesel engines for 160-200,000hp for all four shafts!

I think the third diagram with the annular arrangement possibly relates to the strip rather than the cruisers. Note that it's clearly on the centreline and very low in the hull, while the general arrangement drawing for the cruisers shows the engines and shafts offset and higher in the hull, as we'd expect. If you look closely at the engine blocks in those drawings, it seems to be two pairs of blocks - each pair looking like a wide, squat H shape - and a single block per shaft, rather than 5 single blocks. Not quite clear what that's trying to represent - possibly banks of cylinders?

WRT the LAA layout, I don't think there's anywhere else for it to go. And if you fire the main armament you're going to shred any aircraft, anyway. Pretty much everyone accepted that as inevitable for anything other than a mid-superstructure catapult.

ETA: 160,000-200,000HP as a power range isn't actually outrageous when compared to some of the other Plan Z era designs. Kreuzer P (uprated Deutschland class, 34kts) was rated at 160,000hp on diesels, while Schlactkreuzer O (33.4kts) was rated at 176,000hp on a combined diesel and steam plant. As I said above, I don't think that's what the drawings are showing, but the actual figures may be pushing towards that.

 

[awhalen61]

It is real, btw: https://cdn.discordapp.com/attachme...enshot_20200620_101057_com.android.chrome.jpg

This is the info from Bundesarchiv

 

[TomcatViP]

Please notice that floating landing strip were regularly used for transatlantic crossing by German mail planes in the 30's (regular but not as intense as today obviously).
They used floating refuelling station made out of cargo with with all the proper arrangements to retrieve plane at sea, refuel them before launching them back to complete their crossing.
The drawing appears to be only a military version of the concept.

https://en.m.wikipedia.org/wiki/Blohm_&_Voss_Ha_139

 

[Jemiba]

The "Schleppsegel" (towed sail) to my opinion would have been unsuitable for landing on, or taking off. It was stabilised by
the wash of the ship only and just gave a ground for picking up a flying boat from the water.
That construction in the drawing actually should be a runway for wheeled aircraft.
I would agree with Hood, that this could have been the idea of someone, who actually wasn't a marine architect. Put into some
good looking drawings, it may well have it onto the desk of someone in the "Amt für Kriegsschiffbau" (department for warship
construction), who probably had to assess it. It seems, that the idea wasn't pursued, so the question may rather be, why those
drawings survived, while certainly lots of others went straight into the wastepaper bin. But that wasn't a, individual case, as we
have seen here other ideas, that were submitted, with the best intentions, by laymen, but obviously didn't pass a closer examination

 

[Dilandu]

Please notice that floating landing strip were regularly used for transatlantic crossing by German mail planes in the 30's (regular but not as intense as today obviously).

Yes, but for flying boats and seaplanes - not wheeled planes.

 

[Wurger]

Probably these drawings were captured by the soviets in Berlin (Marinekonstruktionsamt?), since I believe the 3rd. drawing (the inflatable airstrip) has stampings and hanwriting in russian. These are interesting documents, although rough concepts. The time frame is coherent with operation "Seelöwe", hence the possibility of supporting amphibious operations. Commerce raiding is also a possibility. The inflatable airstrip is, perhaps, the most intriguing aspect, but it has a much less less complicated forerunner in the inflatable mat "Schleppsegel", used to recover seaplanes and floatplanes. Jens is most probably right regarding the Voith-Schneider propellers, but the Graf Zeppelin had also two sets, although intended to steer in the Kiel-Kanal.

 

[Grey Havoc]

Please notice that floating landing strip were regularly used for transatlantic crossing by German mail planes in the 30's (regular but not as intense as today obviously).
They used floating refuelling station made out of cargo with with all the proper arrangements to retrieve plane at sea, refuel them before launching them back to complete their crossing.

Forgot those civilian ones.

 

[Wurger]

Can you trace the smokestacks? The aircraft are also puzzling, and it`s curious that when sketching planned ships the german designers where usually accurate drawing embarked airplanes. We have a few threads within our forum with such examples.

 

[TomcatViP]

Please notice that floating landing strip were regularly used for transatlantic crossing by German mail planes in the 30's (regular but not as intense as today obviously).

Yes, but for flying boats and seaplanes - not wheeled planes.

Yes obviously. Although I do remember at least one B&W video of a floating landing strip for wheeled aircraft under test by the Brits.

 

[Dilandu]

Yes obviously. Although I do remember at least one B&W video of a floating landing strip for wheeled aircraft under test by the Brits.

Yes, but it wasn't blue water project; it was literally the floating airstrip for amphibious support (to cover the beachhead before land-based airstrips could be established)

 

[Wurger]

Nick Sumner wrote:

Someone named Stefan Bachi has posted the following drawings under the title ATLANTIKBOMBER-KREUZER and GROßER Atlantikbomber-Kreuzer

Nick, is there a way for you to ask Stefan Bachi to provide better resolution pictures? The specs would be more enlightning...

 

[Jemiba]

Had another look at those drawings, and I'm not really sure, but the header in the upper left corner actually seems to say
"Atlantik Bomber Kreuzer", so the inventor quite probably had blue water operations in mind, not just amphibious support.



To me, the way those aircraft are stored, is the most striking clue, that it was just an "idea". The question about the smokestacks
is valid, but even on official designs, they often weren't recognisable, as you can see, for example on the pre-designs to "Panzerschiff A"
( https://www.degruyter.com/view/journals/mgzs/3/1/article-p35.xml , sketch 3 to 6), maybe their size a bit underestimated.
And Carlos is quite right about those drawings in Russian hands, I think, these are definitely Cyrillic letters.

 

[Wurger]

Thanks for your input, Jens! Commerce raiding is the most plausible task in mind, but I wouln`t rule out, given the date, support to combined operations (using the british parlance). I would concur to the "rough" nature of the concept given the sketchy drawings. I`ve noticed the rather odd prow, much like a icebreaker. A product of Operation Weserübung? The turrets are also puzzling, and I cannot read it as a 280mm or a 203mm triple turret. If it is 203mm, then it would fit this one I`ve posted some years ago:

https://www.secretprojects.co.uk/threads/kriegsmarine-triple-20-3-cm-turret.18915/
The bombers are also a mistery, as well as the launching system. It seems to show 3 catapults, meaning that the aircraft were to be launched sideways and the floating mat would be just to landing. But there are no cranes for retrieving the landed aircraft in the airstrip.

 

[Nick Sumner]

Nick Sumner wrote:

Someone named Stefan Bachi has posted the following drawings under the title ATLANTIKBOMBER-KREUZER and GROßER Atlantikbomber-Kreuzer

Nick, is there a way for you to ask Stefan Bachi to provide better resolution pictures? The specs would be more enlightning...

I have pm'd him with that request and invited him over here to take a look.

 

[ptdockyard]

Thanks for your input, Jens! Commerce raiding is the most plausible task in mind, but I wouln`t rule out, given the date, support to combined operations (using the british parlance). I would concur to the "rough" nature of the concept given the sketchy drawings. I`ve noticed the rather odd prow, much like a icebreaker. A product of Operation Weserübung? The turrets are also puzzling, and I cannot read it as a 280mm or a 203mm triple turret. If it is 203mm, then it would fit this one I`ve posted some years ago:

https://www.secretprojects.co.uk/threads/kriegsmarine-triple-20-3-cm-turret.18915/

Excellent! Thanks for posting this. I had the drawings for the triple 203cm turret from the old Warship Projects board and managed to lose them.

It is somewhat easier to read the text on the "C" ( or "X") turret and I am fairly certain it says 203mm. Scale wise compared to the planes that makes sense.

Dave

 

[Tzoli]

Actually the cranes are evident on the top view drawings having 10 altogether for both proposals but they are missing on the side views, and for such large two engine bombers you need strong heavy cranes. It is also weird that 4 cranes were associated for the 2nd and 3rd aircraft storage but only 2 for the 1st or front one!

 

[Dilandu]

( https://www.degruyter.com/view/journals/mgzs/3/1/article-p35.xml , sketch 3 to 6), maybe their size a bit underestimated.
And Carlos is quite right about those drawings in Russian hands, I think, these are definitely Cyrillic letters.

Well, this is clearly Russian, and reads as "Cruiser-atlantic raider (with) fighters, displacement 5200 tons, schenatic blueprints" Then some incomprehensible words - maybe the name of presumed author - and "Berlin, 1940".

 

[Wurger]

Tzoli wrote:

Actually the cranes are evident on the top view drawings

Indeed they are!

 

[Parasitkaffee]

Hello Together Here are ALL informations I Found about the Atlantikbomber Kreuzer and Großer Atlantikbomber Kreuzer

Thats All what Exist in The Marinearchiv Freiburg .

 

[Wurger]

Parasitkafee wrote:

Hello Together Here are ALL informations I Found about the Atlantikbomber Kreuzer and Großer Atlantikbomber Kreuzer

Welcome aboard, Parasitkafee! Many thanks for sharing this great stuff!

 

[Dilandu]

Hello Together Here are ALL informations I Found about the Atlantikbomber Kreuzer and Großer Atlantikbomber Kreuzer

Hello from Mother Russia!

P.S. Hm, interesting that Russian who wrote hand-written notes insisted that the cruiser is armed with nine fighters - despite the German text clearly indicated bombers.

 

[Wurger]

The original text mentions 6 big fast bombers or 12 fighters.

 

[Dilandu]

The original text mentions 6 big fast bombers or 12 fighters.

Well, Russian handwriting clearly mention nine fighters.

 

[Parasitkaffee]

Well, Russian handwriting clearly mention nine fighters.
[/QUOTE]


But The German Writing tells 9 modern Bombers OR 12 Fighters

 

[Parasitkaffee]

I think one day I build a scale model ship of this strange idea

 

[Wurger]

It gets more interesting as we see more details:

there`s "break and stabilizer rudders" between the fore main battery turrets, in both projects. It should strenghten Jens`s idea that the Voith-Schneider propellers (which were retractable) were for stabilization purposes;

displacement are a mere 4350 and 5200 tons;

the (thin) armour belt is curious, stretching all over the hull from bow to stern. My uneducated bet is to reinforce the ship against ice;

The stern sponsons/rigs are for the submersible net tractor remote control cable and the sir supplying hoses to the inflatable airstrip. If this is corret we should see the plastic covered"aufsatzsttelle"/service area side by side with the bow;

although with a bigger punch (3x3 203mm) than Hipper class heavy cruisers, they would be smaller at 190 meters but faster at 38 knots;

the mothership-borne 6 bombers are rather puzzling, weighing 72 or 78 tons total, depending on the Atlantikbomber-Kreuzer or the Grosse Atlantikbomber-Kreuzer. That puts it in the Ju 88 class, but it does not resembles the Junkers aircraft, except for the ventral gondola. The double oleo strut landing gear is more akin to the He 111, although the early Ju 88 prototypes had them, but different in layout.

 

[Arjen]

Reinforcement for cruising in icy waters would tally with the strange bow and stern shapes.

 

[Dilandu]

It gets more interesting as we see more details:

Engineer Hans really wanted to persuade his superiors that he is doing important job, and most definitely should not be conscripted...

 

[Wurger]

Arjen wrote:

Reinforcement for cruising in icy waters would tally with the strange bow and stern shapes.

Well put, but I compared the hull with german icebreakers from the late 1880`s `till 1945. although the older ones are pretty much the same as the Atlantikbomber kreuzers, here are the newer ones (Taken from Erich Gröner`s "Die Deutsche Kriegsschiffe 1815-1945", volume 6):

 

[Nick Sumner]

The very flared bow is a common trait of German aircraft carrying ships of this vintage. I think its meant to slow down up-down movement of the hull but can't help think that problems with 'slamming' of the bow would occour in even comparatively moderate sea states. The inexplicable aircraft might simply be that with aircraft tending to go out of service quite rapidly and ships taking time to build the designer might have just put in his ideas for a generic twin engined bomber.

 

[Nick Sumner]

Something else I find absolutely bonkers is the shape of the armour belt which seems to taper at each end. Could this design possibly be something like KW 45 - a commercial design sent speculatively to K-Amt to try and get a contract?

 

[Roodbaard1958!]

Hello Together Here are ALL informations I Found about the Atlantikbomber Kreuzer and Großer Atlantikbomber Kreuzer

Thats All what Exist in The Marinearchiv Freiburg .

Good job, still I have one question. I thought I saw a third design dating 1940 from a convoy cruiser on the site of the Bundesarchiv, but I can't find it back. Are you familiar with such a design? Im not sure while I accidentally push a button and it disappeared, Ron