22 Aug 1936: launched by the Howaldtswerke A.G., Hamburg, yard number 751, 11 Oct 1936 delivered to the Hamburg-Südamerikanische Dampfschiff-Gesellschaft, Hamburg as Belgrano.
Measured 6095 grt / 3548 nrt / 9627 tdw, powered by an 8-cyl. 2-stroke cycle MAN oil engine with 3350 H.P., service speed 13 kn.
26 Aug 1939: warned by German radio message about outbreak of hostilities on 1 Sept 1939, returned to Hamburg via Rotterdam.
21 March 1940: requisitioned by the German Navy (Kriegsmarine) for Unternehmen Weserübung, the occupation of Denmark and Norway on 9 April 1940.
15 April - 5 July 1940: made several runs between Danish ports and Oslo, supplying German army forces.
Aug 1940: redesignated A-6 by the Kriegsmarine for Unternehmen Seelöwe, the planned invasion of Great Britain.
12 Sept 1940: whilst in convoy off Hoek van Holland attacked by a British Bristol Blenheim bomber, no noteworthy damage inflicted, as well as on patrol boat Vp-1507 (354 grt / 1937).
Sept 1940 - Jan 1941: converted into a mine clearance vessel with special equipment to detonate mines of various kinds to clear waterways for following convoys or flotillas. Commissioned 17 Jan 1941 as Sperrbrecher 11 into the 1st Sperrbrecher Flotilla. Armed with 2 x 10.5-cm guns, 4 x 3.7-cm guns and 10 x 20-mm AA-guns.
22 June 1941 - July 1942: cleared mines in the Baltic Sea off Liepaja (Libau) and Ventspils (Windau). A cross-dipole was installed on the stem (see photo) in spring 1942 to clear traverse lying mines.
19 July 1941: whilst off the Courland coast attacked by the Soviet submarine S-11 at 1635 h about 10 miles NW Palanga (Polangen). S-11 radioed the vessel as sunk, but in fact Sperrbrecher 11 was missed by the torpedo, as well as the escorting minesweepers M-1801 and M-1802.
Aug 1942: clearing bottom mines off the Dutch coast, acted also as escort vessel for a minelaying operation N of Terschelling.
23 Oct 1942: at 0345 h severe minehit in position 53.31.30N 04.55E, near Ameland, vessel broke in two but stayed afloat on loaded buoyance material. Towed into Hamburg via Borkum for repairs at Blohm & Voss.
31 May 1943: repairs completed, new foreship installed. Resuming mine clearing service in the North Sea.
Nov 1944: transferred to Baltic Sea, allocated to the 3rd Sperrbrecher-Flotilla.
4 Jan 1945: again severe minehit, this time off Aarhus when running onto British air laid mine. Furthermore only used as a barrack vessel in the Flensburger Förde.
9 May 1945: in Kiel taken as prize by British troops.
1945 - 1947: base ship at Hamburg for the German Mine-Sweeping Administration (GM/SA).
20 Sept 1947: seized by Great Britain, due to severe mine damage no further use planned.
24 Sept 1947: towed from Hamburg to Hull, sold to T. W. Ward Ltd., Inverkeithing for breaking up.
1948: former Sperrbrecher 11 was scrapped at Inverkeithing.