German submarine U-552 was a Type VIIC U-boat built for Nazi Germany's Kriegsmarine for service during World War II.

U-552 was involved in two controversial actions: On 31 October 1941, she sank the USS Reuben James, the first US Navy warship to be lost in World War II; this was at a time when the US was still officially neutral, and caused a diplomatic dispute.

U-552 had an unusually long service life, surviving to the end of World War II; after evacuating from her French base during the spring of 1944, she operated on training duties in the Baltic Sea until she was decommissioned in February 1945.

The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder, supercharged diesel engines producing a total of 2,800 to 3,200 metric horsepower (2,060 to 2,350 kW; 2,760 to 3,160 shp) for use while surfaced, and two Brown, Boveri & Cie GG UB 720/8 double-acting electric motors producing a total of 750 metric horsepower (550 kW; 740 shp) for use while submerged.

The remainder of her later patrols were all conducted from the French city, which gave her easy access to the Atlantic Ocean and allowed her more time at sea.

… Steamer breaks completely in the center, deck awash, ends continue to float.” (Beacon Grange, 10,119 tones, 2 casualties) During the afternoon of 28 April 1941, a historic battle was underway about 180 miles south of Iceland.

The U-123 (Karl-Heinz Moehle), had spotted Convoy HX-121 and called in U-65 (Joachim Hoppe), U-95 (Gerd Schreiber), U-96 (Heinrich Lehmann-Willenbrock), and U-552 (Erich Topp) for the kill.

About 6 minutes later, Topp closed in on the already stricken ship and fired a fourth torpedo as a coup de grace into Nerissa's aft starboard side while her crew and passengers were launching lifeboats.

All of these attacks occurred off the northwest coast of Ireland, and once U-552 returned to St. Nazaire on 2 July 1941, she had amassed a total of 24,401 GRT from the ships she had sunk.

[11][12] On 31 October 1941, USS Reuben James was one of five destroyers escorting convoy HX-156, close to the coast of Iceland, about 600 nmi (1,100 km; 690 mi) west of the island.

Reuben James had just begun turning to investigate a strong direction-finder bearing when a torpedo launched from U-552 struck her port side and caused an explosion in her forward magazine.

The stern remained afloat for around five minutes before sinking; unsecured depth charges compounded the damage, exploding as they sank and killing survivors in the water.

The sinking of the Reuben James did not lead the US to declare war on Germany; it did, however, provide a pretext to officially transfer the US Coast Guard from its peacetime role as an arm of the US Treasury Department to a wartime function as part of the US Navy.

Congress also amended the Neutrality Act to permit the arming of US-registered merchant ships and authorized them to enter European waters for the first time since 1939.

[15][16] In 1942, again commanded by Erich Topp (who later became an admiral in the postwar Bundesmarine), U-552 participated in the "Second Happy Time" (Operation Drumbeat or Paukenschlag), during which German submarines had great success against unescorted American merchantmen sailing alone along the eastern seaboard of the US.

The corvette machine-gunned the submarine and hit the conning tower with a four-inch shell, causing severe damage and forcing Topp to return to base for repairs.

[17] U-552 was badly damaged by heavy seas during another patrol and was put into port for repairs, during which Topp was promoted and replaced by a more cautious commander, Klaus Popp.

The destruction of the SS David H. Atwater, in the Atlantic Ocean 10 nmi (19 km; 12 mi) off Chincoteague, Virginia, was one of the more controversial actions of the Kriegsmarine during the Second World War, primarily due to the manner of the sinking.

[18] On the night of 2 April 1942, at the height of the U-boat offensive against US shipping known as the "Second Happy Time", the unarmed coastal steamer David H. Atwater was en route from Norfolk, Virginia, to Fall River, Massachusetts,[19] with a full load of 4,000 tons of coal.

The Legare found a second lifeboat with a body aboard; the boat was discovered to have been riddled by gunfire, and lent strength to the widespread belief at the time that U-boats were deliberately murdering the survivors of ships they had sunk.

Whilst on this duty, Topp sank a small British minesweeper and later a cargo ship, but failed to enter the Straits of Gibraltar or seriously threaten the landings.

During 1943, U-552 was increasingly unable to serve effectively against the well-prepared and organized Allied convoy system, a fact reflected by her failure to sink a single ship during her two patrols into the North Atlantic Ocean.

In 1944, she had a single patrol, but was unable to close with or threaten any Allied convoys, so was withdrawn to Germany in April 1944 for use as a training vessel in the 22nd U-boat Flotilla, a role she fulfilled until she was decommissioned in February 1945.