WW1 U Boat Types
With thanks to Michael Lowrey for this description of the various types of WW1 U Boats.
During World War I, there was not one standard type of German submarine. Rather, the Kaiserliche Marine made use of a variety U-boats types, from very small coastal types to extremely large U-cruisers.
The larger submarines were numbered in the U-series. After the war began, the Kaiserliche Marine ordered smaller submarines, both torpedo attack boats and minelayers. The torpedo-attack boats were numbered in the UB series while UC boats were designed to lay mines. There were three classes of both the UB and UC types, each getting progressively larger. Thus it was possible for three German U-boats to have the same number, one in the U series (like U 32), one in UB series (UB 32), and one in the UC series (UC 32).
U-series types
Early kerosene-powered U-boats
The German navy took delivery of its first submarine, the 238 ton, kerosene (paraffin)–powered U 1, in February 1906. Its armament was a single bow torpedo tube. The technology developed quickly though, and subsequent types were larger, faster, and better armed. All possessed a distinctive large hinged funnel, needed to exhaust the fumes from the kerosene engines.
When the war began, the Kaiserliche Marine had 14 kerosene-powered boats in operational service (U 5 through U 18); earlier types were relegated mainly to training uses. Eleven of the 14 were lost by mid-1916 when the surviving boats transferred to the U-Schule, the U-boat training command in Kiel.
U-series diesel-powered torpedo attack boats
A critical step in the evolution of German submarines came in late 1910 and early 1911, when the Kaiserliche Marine ordered improved submarines from the Imperial Dockyard Danzig and the Germaniawerft. These new boats numbered from U 19 were fitted with diesel engines, which proved to be a far superior technology for propelling a submarine on the surface and charging its batteries than kerosene engines. These boats also had larger 50cm (19.7 inch) torpedo tubes.
During the war, these U-series diesel-powered torpedo attack boats proved highly effective. Though not an initial design requirement, the boats had enough range and sea-keeping ability to sail from Germany to the Austrian ports in the Adriatic or conduct month-long patrols in the Atlantic.
A variety of classes were built but they all shared the same general characteristics. Earlier types were 64 to 67 meters long with two bow and two stern torpedo tubes. Later types could be a little longer and often had four instead of two bow torpedo tubes. Gun armament varied but a 105mm/45 caliber gun forward and an 88mm/30 caliber gun aft was fairly typical from late 1917 on. Longer-barreled versions of the 88mm gun were at times also used.
UEI (U 71 class) minelayers
German naval doctrine placed great importance on mine warfare, with Kaiserliche Marine light cruisers and destroyers fitted for minelaying. In early 1915, the German navy also ordered 10 large minelaying submarines of the UEI class. Numbered U 71 through U 80, these vessels carried 34 mines. The design was made as simplistic as possible to allow for quick construction. UEIs were fitted with a single deck gun of either 105mm or 88mm aft of the conning tower. They had limited torpedo attack capacity, with only a single external torpedo tube being fitted at the bow and stern.
UB Boats
The 17 UBI boats (UB 1 to UB 17) were ordered in November 1914 and delivered in the first half of 1915. These very small submarines had a single diesel engine, a single electric motor, and only one propeller. Armament was a pair of 45 cm (17.7 inch) torpedo tubes; no torpedo reloads were carried. Displacement was 127 tons surfaced and 142 tons while submerged. As might be expected, these small boats were rather slow and had a rather limited range.
The 30 boats of the UBII class (UB 18 to UB 47), ordered in the spring and summer of 1915, were a considerable advance. They were still fitted with only a pair of bow torpedo tubes but these were of the larger 50 cm (19.7 inch) type and reloads were carried. A deck gun was also fitted, with the 88mm/30 caliber weapon being standard from the fall of 1916. UBIIs were somewhat faster — they were capable of 9.2 knots — and carried enough fuel to regularly remain on patrol for two weeks.
The UBIII (UB 48 and up) was a torpedo-attack version of the UCII minelayer. The design retained the duel rudders of the UCII, along with its single stern torpedo tube. The major difference between the two classes was forward, with the UBIII having four internal bow torpedo tubes. A single 105mm/45 caliber or 88mm/30 caliber gun was fitted immediately in front of the conning tower. Though sometimes described as a “coastal” type, UBIIIs were used in the Mediterranean and by the High Seas Fleet like U-series diesel torpedo-attack boats.
UC boats
In November 1914, the German Navy also ordered 15 small submarines of the UCI type (UC 1 to UC 15). These boats’ primary armament was mines; 12 were carried, two each in six chutes in the forward portion of the boat. No torpedo tubes were fitted to UCIs and only boats operating in the Black Sea carried a small deck gun. Like the UBIs, UCIs had a single diesel engine, a single electric motor, and only one propeller. The range-limited UCIs entered service in the spring and summer of 1915.
The UCII (UC 16 to UC 79) was a much more powerful, medium-sized minelaying U-boat first ordered in August 1915. Like UCIs, UCIIs had six mine chutes forward but these now carried three mines each. That though is where the similarity ended. UCII’s weren’t limited to just minelaying; they also were quite capable in the torpedo attack role and carried an 88mm/30 caliber deck gun. The torpedo tube arrangement was unique, with an external deck-level torpedo tube mounted to each side of the mine chutes. Reloads for these bow tubes, if carried, were simply lashed to the deck. The type also had a conventional stern torpedo tube.
UCIIs had sufficient range to sail from Germany to the Austrian ports in the Adriatic.
This type proved highly successful, and provided the basis for the World War I UBIII and UCIII types, with the UBIII being further developed into the Type VII, the most common U-boat class of World War II.
The UCIII (UC 80 and up) was an improved version of the UCII. None were used operationally during the war.
During World War I, there was not one standard type of German submarine. Rather, the Kaiserliche Marine made use of a variety U-boats types, from very small coastal types to extremely large U-cruisers.
The larger submarines were numbered in the U-series. After the war began, the Kaiserliche Marine ordered smaller submarines, both torpedo attack boats and minelayers. The torpedo-attack boats were numbered in the UB series while UC boats were designed to lay mines. There were three classes of both the UB and UC types, each getting progressively larger. Thus it was possible for three German U-boats to have the same number, one in the U series (like U 32), one in UB series (UB 32), and one in the UC series (UC 32).
U-series types
Early kerosene-powered U-boats
The German navy took delivery of its first submarine, the 238 ton, kerosene (paraffin)–powered U 1, in February 1906. Its armament was a single bow torpedo tube. The technology developed quickly though, and subsequent types were larger, faster, and better armed. All possessed a distinctive large hinged funnel, needed to exhaust the fumes from the kerosene engines.
When the war began, the Kaiserliche Marine had 14 kerosene-powered boats in operational service (U 5 through U 18); earlier types were relegated mainly to training uses. Eleven of the 14 were lost by mid-1916 when the surviving boats transferred to the U-Schule, the U-boat training command in Kiel.
U-series diesel-powered torpedo attack boats
A critical step in the evolution of German submarines came in late 1910 and early 1911, when the Kaiserliche Marine ordered improved submarines from the Imperial Dockyard Danzig and the Germaniawerft. These new boats numbered from U 19 were fitted with diesel engines, which proved to be a far superior technology for propelling a submarine on the surface and charging its batteries than kerosene engines. These boats also had larger 50cm (19.7 inch) torpedo tubes.
During the war, these U-series diesel-powered torpedo attack boats proved highly effective. Though not an initial design requirement, the boats had enough range and sea-keeping ability to sail from Germany to the Austrian ports in the Adriatic or conduct month-long patrols in the Atlantic.
A variety of classes were built but they all shared the same general characteristics. Earlier types were 64 to 67 meters long with two bow and two stern torpedo tubes. Later types could be a little longer and often had four instead of two bow torpedo tubes. Gun armament varied but a 105mm/45 caliber gun forward and an 88mm/30 caliber gun aft was fairly typical from late 1917 on. Longer-barreled versions of the 88mm gun were at times also used.
UEI (U 71 class) minelayers
German naval doctrine placed great importance on mine warfare, with Kaiserliche Marine light cruisers and destroyers fitted for minelaying. In early 1915, the German navy also ordered 10 large minelaying submarines of the UEI class. Numbered U 71 through U 80, these vessels carried 34 mines. The design was made as simplistic as possible to allow for quick construction. UEIs were fitted with a single deck gun of either 105mm or 88mm aft of the conning tower. They had limited torpedo attack capacity, with only a single external torpedo tube being fitted at the bow and stern.
UB Boats
The 17 UBI boats (UB 1 to UB 17) were ordered in November 1914 and delivered in the first half of 1915. These very small submarines had a single diesel engine, a single electric motor, and only one propeller. Armament was a pair of 45 cm (17.7 inch) torpedo tubes; no torpedo reloads were carried. Displacement was 127 tons surfaced and 142 tons while submerged. As might be expected, these small boats were rather slow and had a rather limited range.
The 30 boats of the UBII class (UB 18 to UB 47), ordered in the spring and summer of 1915, were a considerable advance. They were still fitted with only a pair of bow torpedo tubes but these were of the larger 50 cm (19.7 inch) type and reloads were carried. A deck gun was also fitted, with the 88mm/30 caliber weapon being standard from the fall of 1916. UBIIs were somewhat faster — they were capable of 9.2 knots — and carried enough fuel to regularly remain on patrol for two weeks.
The UBIII (UB 48 and up) was a torpedo-attack version of the UCII minelayer. The design retained the duel rudders of the UCII, along with its single stern torpedo tube. The major difference between the two classes was forward, with the UBIII having four internal bow torpedo tubes. A single 105mm/45 caliber or 88mm/30 caliber gun was fitted immediately in front of the conning tower. Though sometimes described as a “coastal” type, UBIIIs were used in the Mediterranean and by the High Seas Fleet like U-series diesel torpedo-attack boats.
UC boats
In November 1914, the German Navy also ordered 15 small submarines of the UCI type (UC 1 to UC 15). These boats’ primary armament was mines; 12 were carried, two each in six chutes in the forward portion of the boat. No torpedo tubes were fitted to UCIs and only boats operating in the Black Sea carried a small deck gun. Like the UBIs, UCIs had a single diesel engine, a single electric motor, and only one propeller. The range-limited UCIs entered service in the spring and summer of 1915.
The UCII (UC 16 to UC 79) was a much more powerful, medium-sized minelaying U-boat first ordered in August 1915. Like UCIs, UCIIs had six mine chutes forward but these now carried three mines each. That though is where the similarity ended. UCII’s weren’t limited to just minelaying; they also were quite capable in the torpedo attack role and carried an 88mm/30 caliber deck gun. The torpedo tube arrangement was unique, with an external deck-level torpedo tube mounted to each side of the mine chutes. Reloads for these bow tubes, if carried, were simply lashed to the deck. The type also had a conventional stern torpedo tube.
UCIIs had sufficient range to sail from Germany to the Austrian ports in the Adriatic.
This type proved highly successful, and provided the basis for the World War I UBIII and UCIII types, with the UBIII being further developed into the Type VII, the most common U-boat class of World War II.
The UCIII (UC 80 and up) was an improved version of the UCII. None were used operationally during the war.
