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Bookshelf & Marketplace / Article about NA XB-70 Valkyrie in Le Fana 7-2018
« Last post by hesham on Yesterday at 05:31:52 pm »

there is a good article about NA XB-70 Valykrie in Le Fana July 2018.
I just get a message, that delivery of my pre-order is
preponed to November, the 9th . Good news !
[Rant mode on]

Naval War College Review Number 67 Vol 2, Marcus O. Jones — who is an associate prof at the U.S. Naval Academy — describes the Type XXI submarine as a good example of Germany’s ‘irrational faith in technology to prevail in operationally or strategically complex and desperate situations.’

The Type XXI as designed by Helmuth Walter was supposed to have a revolutionary new peroxide fuelled propulsion system that didn’t require air for combustion. The design had a ‘double-bubble’ hull to permit storage of the peroxide fuel. This meant that in theory the boats were compelled to only surface rarely to recharge their batteries, they were fast enough to shadow convoys and could run silent for 60 hours at five knots. They could also ‘sprint’ for an hour and a half at a speed of 16 knots. By contrast preceding classes of U-boat could not travel faster than eight knots submerged and then only for short periods. The new design also featured various sensors, including radar and sonar and an advanced passive sonar to detect enemy ships. It certainly seemed excellent on paper promising amazing performance and war-winning capabilities but the reality was to be very different. The Type XXI was poorly designed and the boats suffered from several technical problems that drastically delayed their entry into service.

The hydraulic torpedo loading systems didn’t work, neither did the steering system and maintenance was nightmarishly difficult. In common with all high speed submarines of this era the boats were difficult and dangerous to manoeuvre while running at their high underwater speeds. The sort of aggressive manoeuvring required to avoid enemy attack tended to cause loss of control and the boat could easily surpass crush depth before control could be restored but worst of all was the peroxide fuelled engines. The fuel created dreadful problems. It was highly corrosive and it was found that fuel usage was far higher than initially predicted. In fact the engines failed so dismally that the boats had to be redesigned with a large battery bank occupying what had been the peroxide fuel compartment instead. However, the new batteries wore out incredibly quickly and had to be replaced after every second patrol. Also the hydraulic torpedo reload gear reduced the number of reload torpedoes from 30 to 23 and rarely worked properly. Although theoretically capable of a ten minute reloading cycle, the best time achieved was fifteen minutes, which was only five minutes less than manual reloading. The reloading equipment meant that the torpedo room couldn’t be used for accommodation making the submarine more cramped for the crew.

The fundamental problem with the Type XXI was that the design had become excessively complex and, in the manner typical of German engineering, the response to over complicated design was to over engineer the solutions. This of course made the Type XXI hard to build and solving the myriad construction problems delayed the whole program by many months. But even if the design had worked exactly as it had been conceived, the few boats that went on patrol were too big, too expensive and demanded extremely careful handling in order to be effective.

The crews of the few submarines that got on to patrol found that even when the boats could be made to work they were operationally inefficient. The automated torpedo reload system was plagued with malfunctions and wasted weight, space and construction effort in a weapon system that relied on constraining weight and space and  having the most rapid construction time possible. When working correctly it reduced reload time to a creditable fifteen minutes  but this proved operationally useless because the attack profile of a submarine involved firing a salvo of torpedoes then getting away as fast as possible to avoid detection and attack. The submarine couldn't fire again while evading detection because that would reveal its position. The speed of advance of a Type XXI boat was no quicker than a Type VII. All of this meant that the ability to quickly reload was rendered useless by operational realities.
The design had four anti-aircraft guns in two twin turrets streamlined into the conning tower, but these caused a lot of flow noise when the boat was submerged making it easier to detect. Having anti-aircraft guns on a submarine that was supposed to evade detection by aircraft by remaining submerged was, in and of itself, irrational to the point of absurdity. The guns added complexity, increased the size of the crew and reduced performance for no advance in capability.

The one feature of the Type XXI that was extremely useful was the ‘snorkel’, a retractable tube that permitted the boats to exchange the air in the hull and run the engines while close to the surface but not actually surfaced thus drastically decreasing the likelihood of detection. This permitted the boats to remain submerged for long periods relying on the snorkel to recharge the batteries.

[Rant mode off]
Does the book focus on the XXI only, or on other designs as well?

It focuses on the XXI and the XXIII, but is worth reading if you're interested in U-Boats. I'd say it's as good as any other of the author's work.
Although it won't be out for awhile, this looks like another fascinating look at a little-known aspect of Axis seapower:

From this book We can expect to see studies about  proposed conversion to Aircraft Carrier of Fourth battleship of the class " Littorio "  : Impero .
Does the book focus on the XXI only, or on other designs as well?

Not true.  The two fully worked up Type XXI's demonstrated that the design worked well (as well as post war testing and use in navies).

The USN post-war report although true and quality control issues was a hatchet-job regarding capabilities.

The Type XXI boats were worse than useless. If this book says anything other than that its just Nazi wunderwaffewank. Sorry.
Although it won't be out for awhile, this looks like another fascinating look at a little-known aspect of Axis seapower:
I got it last week. Lots of photos I've never seen before - probably going to be the definitive work for some time.
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