German WW1 Steam-U-Cruiser


ACCESS: Top Secret
28 January 2008
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Hi everybody

I have found a very secret german submarine project of 1918
It is a Steam-Turbine powered Submarine for long range.

In german:
Der Bau von U-Kreuzern in Deutschland sollte seine Höhepunkt mit den Fahrzeugen des Typs 44 (auch als UD-Boot bezeichnet , aber nicht identisch mit den 1914 fertiggestellten UD-Booten) erreichen. Nur ein Boot (UD-1) ist im Februar 1918 in der Kaiserlichen Werft, Kiel, auf Kiel gelegt, aber bis Kriegsende nicht mehr fertiggestellt und in der Nachkriegszeit abgebrochen worden.

Engines: Dampfturbinen 4x 6000 PS, Dieselgeneratoren 2x 450 PS, Elektromotoren 2x 1900 PS
Length: 125m, Bright : 10,5m
Armament: 6x Torpedo tubes ,3x or 4x 15,0cm cannons
It is also known as UD-1, Projekt 50 and Typ 44.
The submarine have a smoke stack on the deck.

Source: Marine-Enzyklopädie

Here is a Pic

Many thanks in advance and many greetings
According to Erich Groener "Die deutschen Kriegsschiffe 1815-1945" :

UD 1, official design project 50 from 1917, 2 steam turbines, 4 boilers, armament
3 to 4 Utof 15L/45, 4 torpeo tubes in the bow, 2 in the stern, crew of 104 men.
Externally very similar to U 139 - 141, with the same arrangement of the armament,
the Utof 15 would have been further away from the conning tower.
Order for construction was given in February 1918, after initial tests of the boilers.
Ordered and prepared material was broken or used otherwise after November 1918.
The original documents were destroyed in 1946.
Hi everybody

Thanks Jemiba for this good information
I have found something, too.

Here about the british K-class Submarines (They are also Steam-Powered)

And I have also found a very, very, very good Picture from the PROJEKT 50

What about the Aircraft on the deck?

Many greetings
Try this site:
you can find a really excelent set of plans of "Projekt 50" You will find it revealling...
Regards from Seville


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Oops! You were faster than me. By the way, I´m interested in WW1 submarines, but I can find little or no drawings about them. If I could find a good set of plans of submarines from this period, I would be very grateful.

P.S. There is an excellent spanish site on german U-boats: where youc an find lots of plans of german unbuit projects, and really interesting diagrams of the construction yards and bunkers. the section about u-boats weapons and sensors is quite good. The site is only in spanish, but the graphics deserve a look.

Regards from Seville
I wonder how this cruiser would compare with the British 'K' Class which was in itself a technological blind alley?
Hi everybody

The K-Class is also Steam-Powered, so....
By the Way here are some good Websites, i have found.

Some Plans for various Subs
German Submarine List

Many greetings
Hi everybody

I have one question, what submarine (planned or built) was the biggest in World War 1 ?
Could it be the Projekt 50 ? What about some other Submarine Projects of World War One ?

Many thanks in advance
The USN had some rather bizarre submarine projects in this time frame, the largest of which was over 20,000tons and armed with 12" guns.

Italy also had some interesting submersible projects whereby the hull could be submerged but the turrets remain above water, the largest was around 23,000tons and armed with 6 x 381mm guns.
Hi everybody

Thanks for information ! red admiral Are there any Pictures of these submarines?

Many greetings
moin1900 said:
Thanks for information ! red admiral
Are there any Pictures of these submarines?

RedAdmiral posted an image of the US concept on an old thread:

As for the Italian semi-submersible monitors, these may be what RedAdmiral refers to:

More here:
I have some recently released views of the other USN submarine cruiser projects that I'll post soon.
Hi everybody

Thanks for this really great stuff everybody !

Many greetings
I'd never heard of this. I've heard of the RN's K-class and I knew that the USN was also looking at steam propulsion but not Germany. I guess designers think alike the world over!

I've no doubt that, if built, they would have had much the same problems as the K-class in regards to habitability, diving time and leaks!
Further to the Projekt 50 Tauchschiff, a while ago I was browsing the net, and someone somewhere has built a large scale model of it (see attached photos).


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Does anyone have anymore data on the specifications of this design? Crew, displacement, range, etc.

Looking at the deck plans the armament would be:

Projekt 50

Torpedo Armament: 10 50cm torpedo tubes (all submerged when surfaced) with 28 torpedos; four bow (four reloads), two (trainable) angled to either port bow or starboard bow (six reloads), one each angled to port aft and starboard aft and two aft (eight reloads, including for aft angled tubes)

Gun Armament: 4 15cm U-Boat guns with ~2,500 15cm rounds

The approximate displacement was 3800 tons surfaced, 4300 tons submerged. Speed was estimated as 25 knots surfaced, 9.5 knots submerged. The problem with UD-1 ( Projekt 50 ) is that for many years all orginal info was thought to be destroyed. The Dreadnought Project drawing was captured by the Russians and was not returned to Germany until the early 90's.

Thus some of the published material concerning torpedo tubes and the number of guns are incorrect. The Projekt 50 drawing is very detailed and one would assume the design was at least nearly finalized.

Anybody have some more pictures of that model?
Hi everybody

I have found another very secret german Submarine Project of WW1 !
It is a armoured submersible long-range commerce raider !
Here is everything I know about this U-Panzerkreuzerprojekt
Double-hull type
Type displacement : 4100 tonnes
Engines: 6000 hp surfaced
2800kW submerged
Range: 13,200nm at 10 kn surfaced
80nm at 4kn submerged
Armament: 10 Torpedo tubes
Crew : 127 men
Also known as Projekt 47 or U-Panzerkreuzer !
This was a project only ! No orders were placed !

Many greetings
This was a WWI project?

EDIT: I wonder if work on this design led to Project 50/UD-1 (also referred to in some sources as Type 44).

Thanks moin1900! You found a couple of very interesting projects indeed.

(Taken from linked thread)
The rear tower seems to be two smokestacks. Was this steam powered? Was this design related to the German cargo submarines?
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