After the invasion of France in those four ships were all captured on shipyards in St. Nazaire in various stages of construction. It was first planned to complete the ships as air control ships (projected names Jupiter , Saturn , Merkur , Uranus ) and from February 1941 the construction was continued under control of the Reichsluftfahrtministerium. In April 1942 they were taken over by the
Kriegsmarine again which completed the ships as fast escort vessels SG1 -SG4 . During operations they proofed to be very weakly
built and bad seagoing ships.

SG1 was commissioned on 09.08.1942 and was attached to the 4th and 6th coast defence flotillas. In August 1943 it was damaged by a mine hit and put out of service. After the war, the ship was taken over by France and was recommissioned in May 1947 as survey vessel Beautemps Beaupré . In 1969 it was reclassified as hulk Q456 and scrapped in 1973.