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‘U-Boats at War in a 100 Objects'
Dealing with topics in a ‘100 objects’ has become a popular way of presenting a fresh perspective on a subject. When done well this approach can be illuminating, bringing together a diverse range of ‘objects’ from the familiar to the obscure. I previously covered the impressive The Third Reich in 100 Objects . Taking the idea into a more specific area is U-Boats at War in a 100 Objects 1939-1945 - another well designed collection. An excellent overview which both introduces the scope of U Boot warfare and delves into some unexpected aspects.
The following excerpt presents three randomly chosen ‘objects’, illustrating the breadth of approach adopted here:
12 The Deck Gun
Although the torpedo is, of course, the weapon most associated with submarines, on the outbreak of the Second World War all Type VII and Type IX submarines were equipped with a deck gun. The gun most widely used was the 8.8cm gun carried on the Type VII. Known officially as tire ‘8.8cm L/45 SK C/35 an U-Boot lafette’, it was designed in 1935 and entered service in 1938. The SK stood for Schiffskanone or Schnellfeuerkanone and ‘35’ the date of original design.
The gun fired a 15kg round with a muzzle velocity of 700mps and a range of nearly 12,000m. A total of 220 rounds were carried on a typical U-Boat. A watertight container on deck held a few rounds for instant use, thereafter shells had to be carried up from the interior of the boat. Tie gun required a crew of three.
The larger Type IX boats carried the more powerful 10.5cm gun, the 10.5cm/45 SK C/32, which fired a 24kg round with a muzzle velocity of 780mps and range of 15,000m. Typical rate of fire was 15 rounds per minute, with a crew of three.
Despite the significant range of both of these weapons, in reality they were only used at relatively close quarters. A U-Boat on the surface in anything other titan a flat calm sea was not a stable gun platform. In fact, the crew were provided with a safety line to prevent them from being washed overboard.The use of the deck gun also placed the U-Boat in a precarious position. With the crew in position, commanded by the Second Watch Officer and a chain of men in the process of supplying the gun with ammunition, the appearance of an enemy vessel would require the gun to be secured and all those on deck crewing and servicing the gun to climb up into the tower and enter the interior of the boat, all of which took time that the U-Boat could ill afford before crash-diving to safety.
Deck guns were thus used most often in what were considered safe circumstances, perhaps intercepting a single enemy merchant, though on more than one occasion the deck gun was known to have successfully shot down an attacking enemy aircraft. As surfacing to intercept enemy vessels became more and more dangerous, it was decided to remove all deck guns and instead to increase the complement of anti-aircraft armament.
The 8.8cm weighed 0.75 tons and the 10.5cm weighed 1.5 tons, so removing these provided a welcome saving in weight and more importantly reduced the drag effect caused by these weapons and allowed a faster crash dive when a boat on the surface was threatened by enemy ships or aircraft.
54 Enigma Quadrant Maps
As well as a full set of navigational maps, German warships including U-Boats used a further set of maps based on a grid system for use when signalling locations using the Enigma coding machine.
On these maps, the seas were divided into large squares, each square known as a Grossquadrat. These Grossquadrats were given a two-letter code. For example, the North Sea coast of the British Isles was in Grossquadrat AN and the Atlantic Coast of the British Isles in Grossquadrat AM. These ‘squares’ were not always uniform in shape or size but as a general rule, a Grossquadrat could have, for instance, a side length of 160 sea miles, so that the Grossquadrat could encompass an area of more than 25,000 square miles, a very large area.
The Quadrat was therefore first subdivided into nine smaller squares on a 3 x 3 grid. These squares were numbered rather than carrying a lettercode.With an edge length of 54miles,these would cover an area of just under 3,000 square miles.These squares were further subdivided into nine small squares, so that a basic Grossquadrat was subdivided into eighty-one small squares.
A further subdivision reduced the square to an edge length of 6 miles, so an area of 36 square miles. The squares were numbered from 11 to 99 using all numbers except those with a zero, so 19 would be followed by 21.
In order to pinpoint a location within a smallest size square, an alphanumeric code would be used, with two letters and four numerals, so AN5145 would indicate a small area of sea off the Firth of Forth on the approaches to the naval base at Rosyth. To indicate a larger general area, the last two digits would be omitted and replaced with zeros, thus AN5100.
These ‘Quadratkarten’ gave the U-Boats an effective and efficient method of transmitting their positions or positions of convoys they had detected back to U-Boat headquarters (BdU). Unfortunately,of course this also depended on the security ofthe Enigma coding system.Once the Allies had cracked Enigma,he Quadratkarten would not help.
57 Toilet Facilities
Toilet facilities are not one of the first things that come to mind when thinking of U-Boats but the correct use of such facilities is not just important but a matter of life and death. Typical ocean-going U-Boats were provided with two toilets, or ‘heads’ in naval parlance.
However, one of these was generally unavailable for the first part of any war cruise as the space inside the toilet was used for storing foodstuffs. This resulted in a crew of fifty or more men being forced to use a single toilet.
The toilet itself was an incredibly tiny closet' with a small toilet bowl. Clearly, given the lack of space on a U-Boat there was no possibility of a ‘septic tank’ into which the toilet could be emptied. The toilet functioned by means of a flush mechanism that had to be operated in a very specific manner to avoid disaster. On flushing the toilet, the contents were emptied into a holding tank, which was then sealed closed by a valve.
Thereafter a second valve emptied the holding tank into the sea. Incorrect operation of tne valves could result in not only the contents of the toilet but seawater under great pressure being vented into the boat. In fact, at least one operational U-Boat, U-1206, was lost due to improper operation ofthe toilet.
The commander, Kapitanleutnant Schlitt, experienced problems operating the toilet and called for one of the engineers to assist. Tire engineer operated the wrong valve, resulting in rapid flooding with sewage and sea water entering the boat. Tris entered the battery compartment below the toilet and caused the release of toxic chlorine gas. The boat was forced to surface to avoid flooding and to vent the poisonous gas, and was attacked by enemy aircraft. Tie damage sustained was fatal and the boat had to be abandoned. Thankfully for the crew, the boat was close to shore and the crew managed to swim to safety.
In order to avoid using the toilet, crew would often make use of receptacles such as empty shell casing and save the contents until it was safe to empty them overboard. One can imagine the mess that would be caused when a boat had to carry out an emergency crash dive and these receptacles ended up being spilled all over the decking, adding to the miasma of unpleasant smells inside a U-Boat. In safe waters far from any enemy presence, crew members could use the ‘outside toilet’ and simply squat over the boat’s safety rails.
This excerpt from U-Boats at War in a 100 Objects 1939-1945 appears by kind permission of Pen & Sword Books Ltd. Copyright remains with the author.