Continued from # 136

This book by KELLY LYDON incorporates a lot of research that he did into the World War I German U-Boat history. We will publish excerpts from his book on a monthly basis, but you can buy your copy right away. Details me at the end of this story.

After the development and commissioning of the KARP Class, there emerged a new class of U-Boat known as the DESIDERATA. Desiderata means something desired and needed - the something desired and needed were speed, design, range and armament. These requirements were to be formulated by the submarine bureau, under the umbrella of the Imperial Naval Office.

U-5 through U-18 were to comprise the DESIDERATA Class. The seeds of a modern U-Boat fleet were being planted and were taking root. However, the hierarchy of the German Admiralty still considered the U-Boat to be experimental and with good reason. U-3 had sunk during her sea trials, killing two of her crew. It was rescued and raised by the U-Boat mothership VULKAN.

Furthermore, the battleship mentality was still in vogue and there were international naval conventions - of which Germany had been a signatory - still in force regarding the conduct of a war at sea. The most significant were the Hague Naval Conference of 18 October 1907 and the London Naval Declaration of 26 February 1909.

Both of these conferences, mindful of the recent Russo- Japan War, articulated the protection of neutral shipping, civilian passengers, preventing the use of mine laying via submarine, the protection of postal correspondence of both neutrals and belligerents on the high seas were considered inviolable, and there was to be the establishment of a Prize Court. Further, Article 112 of German Naval Regulations provided for the safety of enemy merchant sailors.

These international naval treaties, as well as the prevailing international law would throw Kaiser Wilhelm II, Chancellor Bethmann-Hollweg, the Foreign Office and the German Naval Staff into an incessant and relentless state of fragmentation and bickering once the U-Boat entered th

A U-Boat in the simplest of terms consists of two bodies: 1) The pressure hull; 2) The exterior hull.

The pressure hull contains the navigational equipment, the living quarters and the propulsion plant. As the U-Boat dives, it must be able to withstand the pressure of the water on the exterior bull while simultaneously maintain a pressurized and livable environment inside the boat.

U-Boat Physics

Once the U-Boat has submerged, its center of gravity, buoyancy and maneuvering had to be constantly monitored and adjusted. This was necessary in order to maintain proper trim and equilibrium. This was accomplished by a series of water tanks, trim tanks, pumps, diving tanks, regulating tanks and hydroplanes for upward and downward motion.

The Archimedean Laws of physics are difficult to repeal. The upthrust must equal the weight or dead load of the boat. While submerged the entire surface of the boat multiplied with the specific weight of seawater must equal the weight of the boat, *including water ballast taken on in order to dive. Germania Werft had developed and put into place a series of tanks which could operate simultaneously. This equipment was known as the Lenz System of diving tanks.

Germania Werft and the technical bureau of the German Navy dictated that the heaviest U-Boat shall be able to maneuver in shallowest of waters and the lightest U-Boat shall be able to dive in the densest of waters. Drinking water, stored food, torpedoes and fuel oil all had to be calculated and compensated for when a U-Boat was submerged, for the weather and sea conditions in the North Sea were hazardous and quite tempestuous. After all, the early U-Boats were originally destined to be secondary weapons of the torpedo boat flotillas and destroyer squadrons in the German Bight of the North Sea.

Furthermore, the island base of Helgoland in the German Bight was to be defended by mines and U-Boats, when the German High Seas Fleet and the British Grand Fleet were to have their Trafalgaresque encounter.

By filling her diving tanks with water, the boat achieves negative buoyancy. Once submerged, the boat's hull has to withstand the constant seawater forces. All U-Boats including the UB and UC series classes from U-5 onward were able to reach a depth of 165 feet. The later U-Kruzers could reach a depth of 250 feet.

In U-3 thru U-8, the collision bulkheads were 16 - 21 mm thick (.64 'inch to .84 inch) and were designed to withstand pressure of 50 meters on the pressure hull. And from U-2 onward, the conning tower had 30mm (1.2 inches) of nickel steel riveted to it. The exterior hull of a U-Boat had an outer skin of 3.5 - 4mm thick ( 14 inch to .16 inch) sheet metal with zinc coating over the entire hull. The upper deck was covered with linoleum.

U-Boat Batteries

One of the most significant costs to the building of a U-Boat was the batteries. The batteries on a U-Boat were the power source for the electric motors while the boat was being propelled underwater. Therefore, the batteries had to be constantly maintained in order to be reliable. The early KARP U-Boats had lead cells with mass plates with peat insulation between the plates and the entire device set in a hard rubber housing.

This peat insulation was replaced with larger surface area plates which increased the voltage or power of the batteries. From U-13 onwards had greater specific capacity in their ampere-hours. Furthermore, there was also the never-ending danger of explosive and toxic gases from the cells.

HARRY's NOTE - ANTHONY STUART MELVILLE-ROSS (1930-+-1991) was the Royal Navy Skipper of a former US Navy S-Boat, known as the Reluctant Dragon, that was given to the British along with two other S-Boats and 50 World War I destroyers. On returning from a patrol, he was on his way to be debriefed with his Squadron Commander when he heard a deafening roar from the dock. His crew was charging batteries and an explosion occurred on board the Reluctant Dragon, killing a member of the crew. The boat was so badly damaged that she was never repaired, but was scrapped.

U-604 was sunk and some of the crew picked up by another U-Boat and later that boat came under attack. The batteries ruptured and the boat filled with chlorine gas so badly that the Skipper of U-604 (Holtring) shot himself with his own pistol because of the extreme pain he suffered. Yes, battery gasses are extremely dangerous.

Air purification system was installed for use when submerged. This system took gases and fumes via fans through caustic potash filters and was recycled as oxygen. This system was developed by the Drager Works and designed to last a 24 man crew for 72 hours. Normal battery life was about four years, with an accompanying cost of abut 220,000 marks per battery set.

U-1 had battery voltage of 130, while U-3 through U-16 had a voltage of 210 volts. The total weight of the batteries varied from 49 tons in U-1; from 82 tons in U-10 and U-12; and 77 tons in U-9 and U-13 through U-16.

In U-1 the engine room and machinery room containing the electric motors were in the stern section of the boat. Forward of the engine and machine rooms are the living quarters. Often times the batteries would be stored beneath the floorboards of the living quarters. Amidships is the control room (Zentralle) and the conning tower housing the depth and diving gauges and navigational equipment. Forward of the central control room are more living quarters and the torpedo room, Also forward near the forward torpedo tubes are the hydroplanes which controlled the upward and downward motion of the boat.

Paraffin, Not Diesel

As I have mentioned before, the main problem with these early U-Boats, namely the KARP and DESIDERATA Classes, was the propulsion plant. The paraffin lamp, supplied by the Korting Bros. of Hannover, was cheap but could be unstable and more important, limited the range of the U-Boat.

In the early 20th Century the diesel engine was not a concept, but a reality thanks to its inventor, German born Rudolf Diesel. As a matter of fact, the diesel engine was to be built for the early KARP Class of U-Boats but the expense and the problem of weight versus performance dictated the use of paraffin burning engines. The firm of Maschinenfiabrik Augsburg-Nijrnberg AG (known as MAN) possessed the patents and technology for diesel engines.

There had been many discussions regarding diesel powered submarines between Germania Werft and MAN, and the technical bureau of the German Navy. These discussions took place between 1904 through 1907. MAN had made various proposals on its diesel engine program to Germania Werft and the navy.

MAN had recommended a 200hp four-stroke diesel engine versus a two-stroke diesel engine. The four-stroke engine made less noise and consumed less fuel, but its arrangement of six fittings and couplings on the crankshaft caused difficulties in starting the engine as well as using the reverse gear. Furthermore, there were problems relating to the torque in the crankshaft and the proper ventilation of the entire engine system.

From an engineering standpoint, the stroke of a diesel is important because it is needed to ignite the engine. Furthermore, as a result of delays in testing and manufacturing; and with various proposals with the diesel engine design, the German Navy built U-5 through U-18 known as the DESIDERATE Class. A total of 14 U-Boats comprised this class, which were all powered by paraffin lamp oil burning engines. They were all ordered and built between April 1908 through May 1910.

Paraffin lamp oil burning engines left a tell-tale blue exhaust cloud which pinpointed the location of the U-Boat

However, it was again the demand of a foreign navy that helped to propel the Imperial Navy to adopt diesel engines. This time it was the Italian Navy.

Italian U-Boat: Atropa

The Italian U-Boat was consigned to the Krupp Germania Werft in March 1911. The boat was named ATROPO, which was one of the three fates in Greek mythology. The Italians were looking to improve their submarine capability in the Adriatic Sea.

Italy had a historic naval rivalry with the Austro-Hungarian Empire dating back to the Battle of Lissa in 1866 in which Italy was defeated. Although Austro-Hungary, Germany and Italy had formed the Triple Alliance, the alliance was never on political-military terra firma, especially when World War I began. The French Navy was the wild card in this international equation.

ATROPO was launched on 22 March 1912 and after sea trials, was delivered to the Italian Navy on 5 February 1913.

The specifications for ATROPO were:

length 50 meters (164 feet)
beam 4.4 meters (14.43 feet)
displacement 231/315 tons
power (diesel) 350 hp Krupp-built diesel engines
power (electric) 100 hp
speed (diesel) 14.75 knots
speed (electric) 7.8 knots
tubes (fwd) two tubes and (aft) none
guns none
AA guns none
compliment 2 officers and 12 men

Moreover, the original top speed was designed for 12 knots but since Germania Werft was late, it was able to give the Italians an impressive top speed of 14.75 knots due to the diesel engines. As with all diesel engines at that time, reverse was achieved via controllable-pitch propellers.

ATROPO spent the war on patrol in the Adriatic, primarily operating against Austrian shipping. On 4 June 1916, ATROPO torpedoed and sank the 1,122 ton Austrian steamer ALBANIEN.

ATROPO was decommissioned on 23 January 1919.

As the Italians built their submarine fleet, they also used Fiat motors of Turin, Italy which bought the diesel design patents from Krupp's Germania Werft.

Norwegian U-Boat Kobben

Another significant German U-Boat prototype, again built for a foreign navy, was the KOBBEN which was designated as UA-1. This time the Norwegian Navy wanted a diesel-powered U-Boat. The design for KOBBEN featured two periscopes and an enlarged bridge/conning tower. Her keel was laid down in 1913, she was commissioned in 1914.

Her specifications were:

length 153.22 feet
beam 15.68 feet
displacement 270/342 tons
power (diesel) 350hp
speed (diesel) 14.2 knots
speed (electric) 7.2 knots
bunkers 13 tons
range (diesel) 900 miles
range (electric) 76 miles
tubes unknown (carried five 45cm torpedoes)
guns single 2 inch deck gun
AA guns none
diving time 67 seconds

KOBBEN was commissioned near the outset of the war. As a consequence, the German Admiralty canceled the contract with the Norwegian Navy and commandeered the boat. KOBBEN was assigned as a schulboot (training boat) to the periscope school.