When development began on the Type XXI U-boat in late 1942, it was proposed to simultaneously develop a smaller version incorporating the same advanced technology to replace the Type II coastal submarine. Admiral Karl Dönitz added two requirements: as the boat would have to operate in the Mediterranean and the Black Sea, it had to be able to be transported by rail, and it had to use the standard 53.3-cm torpedo tubes.
The development of the Type XXIII was given a high priority, with an emphasis on using existing components as much as possible. To reduce development time, Hellmuth Walter designed the new submarine based on the previous Type XXII prototype. By 30 June 1943 the design was ready and construction began in parallel at several shipyards in Germany, France, Italy and German-occupied Russia. The lead contractor was Deutsche Werft in Hamburg.
As with the Type XXI, the Type XXIII was intended to be constructed in sections, various modules being produced by different subcontractors. Some were to be assembled at foreign yards, including U-2446 through U-2460 at the Deutsche Werft yard at Mykolaiv. These were reassigned to the Linzner yard on 1 May 1944 and subsequently cancelled. In the end, circumstances meant that construction was concentrated at Germaniawerft in Kiel and Deutsche Werft in Hamburg, Germaniawerft building 51 and Deutsche Werft 49. Of the 280 submarines ordered, only 61 entered service, and only 6 ever carried out a war patrol.
Displacement: 234 t (230 long tons) surfaced
258 t (254 long tons) submerged
Length: 34.7 m (113 ft 10 in)
Beam: 3 m (9 ft 10 in)
Draft: 3.67 m (12 ft 0 in)
Propulsion: 1 × MWM RS134S 6-cylinder diesel engine, 575 hp
1 × AEG GU4463-8 double-acting electric motor, 572 hp
1 × BBC CCR188 electric creeping motor, 35 hp
Speed: 9.7 knots (18 km/h) surfaced, 12.5 knots (23 km/h) submerged
Range: 2,600 nmi (4,800 km) at 8 kn (15 km/h; 9.2 mph) surfaced, 194 nmi (359 km) at 4 kn (7.4 km/h; 4.6 mph) submerged
Test depth: 180 m (590 ft)
Armament: 2 bow torpedo tubes
January 15, 2013
I have been commissioned to build up an old (circa 1985) kit of a German Type XXIII u-boat, originally sold by a company called 32nd Parallel, which is long out of business now.
The model will actually feature two working torpedo tubes when complete, and I'm pretty excited as this will be my first foray into the world of working torpedos!
The kit is actually constructed mostly of styrene plastic and I have to say that I'm pleasantly surprised by how well it fits. The level of professionalism in the kit is excellent, with detailed instructions and many blueprints and diagrams.
The kit was originally designed as a dry hulled boat. Since then the WTC (watertight cylinder) concept has evolved and is (at least in my opinion) far superior. As such my first task was to chop out the internal pressure hull to make room for a 2.5" Caswell SubDriver unit.
I hope to have this project complete within 30 days or so!
January 28, 2013
Lots of great progress to share!
The WTC is nearing completion. I am currently installing two small linear servos to actuate the torpedo tube doors and the torpedo release mechanism. That done, it should be ready for service.
The hull took a bit longer to assemble than I'd planned due to the number of scratchbuilt pieces that I needed to build. I also added some (slightly over-scale) weld lines to the otherwise featureless hull just for visual interest. I think they add a lot to it.
February 14, 2013
Lots of work, but not much to show for it!
The biggest challenge over the last weeks was coming up with a reliable and simple launching mechanism for the torpedoes. I used the 32nd Parallel design for the actual torpedoes, and then finally settled on a modified version of Dave Merriman's design that incorporates a forward stop that is released with a rod that simultaneously pushes the weapon off its seals and out the tube.
I went through about three different designs before finally coming up with this one as the simplest and easiest to build and maintain.
My bench tests have gone very well and I'm working on fabricating the second launcher. Implementing the linkages that will allow both tubes to fire separately from a single channel will be challenging, but should be doable.
March 7, 2013
I've been away from home for the last week, but I did manage to get a lot more done on the boat!
The two torpedo launchers are now complete and operational. I've built four torpedoes for it, two with straight fins, one with a left handed cant and one with a right handed cant. In my tests, the torpedo with the fins slanted towards the left turned to the left at launch. It actually makes sense to me for when its running on the surface. I'm anxious to see if the straight fins cause straighter runs.
Enjoy the pics and video! I'm hoping to have her finished and painted up within the next week or so.
April 25, 2013
The sub turned out absolutely beautifully and you'll see from the attached video that she's a great performer as well.
Unfortunately due to time constraints I never did manage to get the torpedo system working reliably. The launchers worked quite well, however the tube firing mechanism was never perfected and was shipped to her owner's home as-is (at his request).
Enjoy these final photos and, of course, the video!