×
Aircraft / Aviation Vehicles & Artillery Small Arms Warships & Submarines Military Ranks Military Pay Chart (2024) Special Forces
HOME
NAVAL WARFARE INDEX
MODERN FLEETS
WARSHIPS BY COUNTRY
SHIPBUILDERS
COMPARE WARSHIPS
SHIPS BY CONFLICT
SHIPS BY TYPE
SHIPS BY DECADE
SHIPS BY CLASS
WWI NAVAL WARFARE

Naval Warfare


SM U-21


Diesel-Electric Attack Submarine [ 1915 ]



Commissioned in 1913, U-boat SM U-21 survived all of World War 1 only to be sunk accidentally in 1919.



Authored By: Staff Writer | Last Edited: 07/31/2019 | Content ©www.MilitaryFactory.com | The following text is exclusive to this site.

VIEW SPECIFICATIONS [+]
U-21 formed the third of the four-strong class of U-19 U-boats in service with the Imperial German Navy heading into World War 1 (1914-1918). The class represented a prewar German attack submarine design and the first in German naval service to feature diesel engines as standard propulsion. The class was pushed into action with the outbreak of war in July of 1914 and netted its first kill in September - U-21 becoming the first submarine in naval history to record the destruction of an enemy surface ship by way of a self-propelled torpedo (HMS Pathfinder). U-21 was built by Kaiserliche Werft Danzig and saw her keel laid down in 1910. Her hull was launched on February 8th, 1913 and she was formally commissioned on October 22nd of that same year.

As completed U-21 displaced at 720 tons (short) when surfaced and 923 tons when submerged. She held a length of 210.5 feet with a beam measuring 20 feet and a draught of 11.8 feet. Drive power was through 2 x MAN 8-cylinder diesel engines driving two shafts for surface travel and 2 x AEG Motordynamos for use submerged travel. Maximum speed (surfaced) was 15.5 knots (9.5 knots submerged). U-21's crew complement totaled 29 and included four officer-level personnel. Armament was 4 x 500mm torpedo tubes and 1 x 88mm SK L/30 deck gun.

As World War 1 began to evolve among its many players, U-21 found herself stationed near the Heligoland archipelago off the coast of northwest Germany. War patrols soon became a way of life for U-boat crews as the British Royal Navy fleet remained a constant threat to German operations in the North Sea and the Atlantic. Her first patrol commenced in August though no action was reported duirng that service and through her second war patrol. It was not until September 5th that U-21 met HMS Pathfinder near the Isle of May when the German submarine first spotted its prey. After a period of maneuvering, U-21 managed a successful torpedo hit on Pathfinder which, in turn, ignited one of Pathfinder's magazines and caused her to explode. The attack killed 261 British sailors. During 1916, U-21 was given a second 88mm deck gun for improved surface attack capabilities.

From September 1914 to June 1917, U-21 managed a lengthy kill record that began with Pathfinder and ended with the Swedish ship "Baltic". Over her wartime career, U-21 completed eleven total patrols and netted 38 merchant vessels along with four enemy warships. Total merchant tonnage equaled nearly 88,000 tons along with 34,575 tons from the warships sunk. Her career took her from the North Sea in 1914 to the Mediterranean during 1915-1917 where she and her crew were called to support a new German ally in Turkey. During the Gallipoli Campaign, U-21 proved instrumental in threatening Allied warships from concentrating useful close support fire for landing ground forces -sinking two (of eighteen present) pre-Dreadnought battleships in the action. She formed a portion of the Black Sea Flotilla and then saw herself commissioned as part of the Austro-Hungarian Navy to allow her free reign in attacking Italian ships - Germany was not yet formally at war with Italy at this point but the Italians were at war with German ally Austria-Hungary. She served the Austro-Hungarian flag as "U-36" until the Italian declaration of war on Germany on August 27th, 1916. For 1917, she was recalled to the North Sea to once-again target British warships. In 1918, she was made part of III U-boat Flotilla and later served in the training role for the rest of the war - which ended with the Armistice of November 11th, 1918.

With the German surrender, U-21 was collected by the British and it was during the operation to bring her to British waters under tow that U-21 took on water and sunk - ending her ocean-going career in full.©MilitaryFactory.com
Note: The above text is EXCLUSIVE to the site www.MilitaryFactory.com. It is the product of many hours of research and work made possible with the help of contributors, veterans, insiders, and topic specialists. If you happen upon this text anywhere else on the internet or in print, please let us know at MilitaryFactory AT gmail DOT com so that we may take appropriate action against the offender / offending site and continue to protect this original work.

Specifications



German Empire
Operators National flag of the German Empire
1915
Commissioned
Imperial Germany
National Origin
Decommissioned, Out-of-Service
Project Status
29
Complement
Type U-19
Hull Class
4
Number-in-Class
U-19; U-20; U-21; U-22
Ships-in-Class


Submerged Attack
Traveling under the surface to search, track, and / or engage or reconnoiter areas.
Maritime Patrol
Active patroling of vital waterways and maritime areas; can also serve as local deterrence against airborne and seaborne threats.
Fleet Support
Serving in support (either firepower or material) of the main surface fleet in Blue Water environments.


210.5 feet
(64.16 meters)
Length
20.0 feet
(6.10 meters)
Beam
11.8 feet
(3.60 meters)
Draught
720
tons
Displacement
925
tons
Displacement (Submerged)


2 x MAN 8-cylinder diesel motors with 2 x AEG Motordynamic electric generators driving 2 x Shafts.
Propulsion
15.5 knots
(17.8 mph)
Surface Speed
9.5 knots
(10.9 mph)
Submerged Speed
1 knot = 1.15 mph; 1 nm = 1.15 mile; 1 nm = 1.85 km


As Built:
4 x 500mm (20") torpedo tubes
1 x 88mm SK L/30 deck gun (1916: 2 x 88mm guns)

1916:
4 x 500mm (20") torpedo tubes
2 x 88mm SK L/30 deck gun


None.


Military lapel ribbon for the Cold War period
Military lapel ribbon for early warship designs
Military lapel ribbon for the Falklands War
Military lapel ribbon for the 1991 Gulf War
Military lapel ribbon for the Korean War
Military lapel ribbon representing modern aircraft
Military lapel ribbon for the Attack on Pearl Harbor
Military lapel ribbon for the Russian Invasion of Ukraine
Military lapel ribbon for the Vietnam War
Military lapel ribbon for the World War 1
Military lapel ribbon for the World War 2

Disclaimer | Privacy Policy | Cookies

2024 Military Pay Chart Military Ranks DoD Dictionary Conversion Calculators Military Alphabet Code Military Map Symbols

The "Military Factory" name and MilitaryFactory.com logo are registered ® U.S. trademarks protected by all applicable domestic and international intellectual property laws. All written content, illustrations, and photography are unique to this website (unless where indicated) and not for reuse/reproduction in any form. Material presented throughout this website is for historical and entertainment value only and should not to be construed as usable for hardware restoration, maintenance, or general operation. We do not sell any of the items showcased on this site. Please direct all other inquiries to militaryfactory AT gmail.com. No A.I. was used in the generation of this content; site is 100% curated by humans.

Part of a network of sites that includes GlobalFirepower, a data-driven property used in ranking the top military powers of the world, WDMMA.org (World Directory of Modern Military Aircraft), WDMMW.org (World Directory of Modern Military Warships), SR71blackbird.org, detailing the history of the world's most iconic spyplane, and MilitaryRibbons.info, cataloguing military medals and ribbons. Special Interest: RailRoad Junction, the locomotive encyclopedia.


©2023 www.MilitaryFactory.com • All Rights Reserved • Content ©2003-2023 (20yrs)