His Majesty´s (S.M. = Seiner Majestät) Submarines
The Imperial German Navy developed three main types of submarines, each type designed for special tasks and areas of operation. In contrast to the Kriegsmarine and with the exemption of the seized submarines, each of the three types of U-boats of the Imperial German Navy started with the unit number “1”. The three main types of U-boats are described below.
The “U”-U-boats” (submarine designation starting with “U”) were large fleet submarines with armament composed of torpedoes, artillery and mines, some 141 U-boats were commissioned by the Imperial German Navy until the end of WW I. The units were designated “U”, followed by sequence number, e.g. U 1, U 2, U 3, and so on. Other than with the “UB” and “UC”-Uboats, this type of submarine had more than three sub-types.
The “UB”-U-boats (submarine designation starting with “UB”) were either smaller or medium sized coastal submarines (Type UB I and UB II) or units for high seas operations (Type UB III), with either mere torpedo armament (Type UB I), respectively armament of torpedoes and artillery (Type UB II and UB III). Some 136 UBoats of this type were commissioned by the Imperial German Navy. The units were designated “UB”, followed by sequence number, e.g. UB 1, UB 2, UB 3, and so on.
The “UC”-UBoats (submarine designation starting with “UC”) were either smaller coastal submarines (Type UC I) with mere mine armament or medium sized minelaying units for high seas operations (Type UC II and UC III) with combined armament of torpedoes, artillery and mines. Some 95 UBoats of this type were commissioned by the Imperial German Navy. The units were designated “UC”, followed by sequence number, e.g. UC 1, UC 2,UC 3, and so on.
This system of designation is unique until today. An advantage might have been the great opportunity to deceive potential enemies in case of war, although nowadays it leads to irritation among Naval enthusiasts, even Naval historians became “victims” to this system of designation. Therefore, UB 79 is not U 79, but a completely different type of submarine.
List of types of German UBoats commissioned in the First World War.
U 1 to U 41, U 43 to U 114, U 117 to U 120, U 122 to U 126, U 135 and U 136, U 139 to U 142,
U 151 to U 157, U 160 to U 165.
Type UB I = UB 1 to UB 17
Type UB II = UB 18 to UB 47
Type UB III = UB 48 to UB 149
Type UC I = UC 1 to UC 15
Type UC II = UC 16 to UC 79
Type UC III = UC 90 to UC 105
Seized (Prize) UBoats
From Norway (ex “A-5”) = UA
From Russia = US-3 (ex Utka and US-3 (ex Gagara), note: US-1 (ex Burevestnik), US-2 (ex Orlan) were two Russian submarines seized during the occupation of Sevastopol, that were never commissioned by the Imperial German Navy.