In Service: 1937 to 1945
                    
                    
                    
                    Ordered:
                    Builder: Abeking 
                    & Rasmussen, Lemwerder
                    
Construction No: 2977
                    
Laid down: 
                    Launched: 17 November 1937
                    
Commissioned: 1937
                    
                    
                    
                    Type: 1936-42 Type R-boat/Räumboot
                    
Class: R21 Class
                    
                    
Displacement: tons standard 123 tons full load
                    
Length: 37 m
                    
Beam: 5.77 m
                    
Draft: 1.38 m
                    
Propulsion: 2 × MAN 8 × cylinder 4 stroke 
                    diesel engines producing up to 2,200 ehp 
                    
Propellers: 2 × Voith-Schneider
                    
Speed: 23.1 knots
                    
Range: nautical miles at knots
                    
Crew: 27 men and officers
                    
Armament:
                    6 × 2 cm MG L/65 C/30
                    carried 6000 rounds
                    
Armour
                    Aircraft:
                    Electronics: 
                    Operators: Kriegsmarine
                    
Variants: 
                    Other: R-boats 
                    Articles: 
                    
                    
                    
                    The R21 R-boat (Räumboot) was built in the 1930s by 
Abeking 
                    & Rasmussen shipyard located in Lemwerder, Germany as a minesweeper or escort vessel for the Kriegsmarine.
                    
                    And which served in the 
1. 
                    Räumbootsflottille during World War II.
                    And after the capitulation of the Third Reich was employed in the 
United 
                    States Labour Service Unit B (LSU-B) which was controlled 
                    by the allies.
                    
                    
                    1937
                    The R-boat R21 is commissioned.
                    
                    
1937
                    The R-boat R21 becomes operational with the 
1. 
                    Räumbootsflottille.
                    
                    
1945
                    The R-boat R21 serves with the 
United 
                    States Labour Service Unit B (LSU-B).
                    
                    
1945
                    The R-boat R21 is seized as a prize of war by the British 
                    and is broken up and scrapped. 
                    
                    
                    
                    
                    
                    
                    
                    
                    
                    
                    
                    
                    
                    German Warships, 1815-1945: Major Surface Vessels.
                    ISBN-10: 0851775330
                    
                    German Warships, 1815-1945: U-boats and Mine Warfare Vessels.
                    ISBN-10: 155750301X
                    
                    German warships of the Second World War.
                    ISBN-10: 0668040378
                    
                    For a complete list of 
sources