History
Name	U-166
Ordered	25 September 1939
Builder	Deutsche Schiff- und Maschinenbau AG, Bremen
Yard number	705
Laid down	6 December 1940
Launched	1 November 1941
Commissioned	23 March 1942
Fate	Sunk, 30 July 1942
General characteristics
Type	Type IXC submarine
Displacement	list error: <br /> list (help) 1,120 t (1,100 long tons) surfaced 1,232 t (1,213 long tons) submerged
Length	list error: <br /> list (help) 76.8 m (252 ft 0 in) o/a 58.7 m (192 ft 7 in) pressure hull
Beam	list error: <br /> list (help) 6.8 m (22 ft 4 in) o/a 4.4 m (14 ft 5 in) pressure hull
Height	9.4 m (30 ft 10 in)
Draft	4.7 m (15 ft 5 in)
Propulsion	list error: <br /> list (help) 2 × MAN M9V40/46 supercharged 9-cylinder diesel engines, 4,400 hp (3,281 kW) 2 × SSW GU345/34 double-acting electric motors, 1,000 hp (746 kW)
Speed	list error: <br /> list (help) 18.2 knots (33.7 km/h) surfaced 7.7 knots (14.3 km/h) submerged
Range	list error: <br /> list (help) 24,880 nmi (46,080 km) at 10 knots (19 km/h) surfaced 117 nmi (217 km) at 4 kn (7.4 km/h) submerged
Test depth	230 m (750 ft)
Complement	48 to 56
Armament	list error: <br /> list (help) • 6 × torpedo tubes (4 bow, 2 stern) • 22 × 533 mm (21 in) torpedoes • 1 × Utof 105 mm/45 deck gun (110 rounds) • AA guns
Service record[1][2]
Part of:	list error: <br /> list (help) 4th U-boat Flotilla (23 March–31 May 1942) 10th U-boat Flotilla (1 June 1942–30 July 1942)
Commanders:	list error: <br /> list (help) Oblt. Hans-Günther Kuhlmann (23 March 1942–30 July 1942)
Operations:	list error: <br /> list (help) 1st patrol: 1–10 June 1942 2nd patrol: 17 June–30 July 1942
Victories:	4 commercial ships sunk (7,593 GRT GRT uses unsupported parameter (help))

German submarine U-166 was a Type IXC U-boat of the German Kriegsmarine during World War II. The submarine was laid down on 6 December 1940 at the Deutsche Schiff- und Maschinenbau AG (DeSchiMAG) yard at Bremen, launched on 1 November 1941, and commissioned on 23 March 1942 under the command of Oberleutnant zur See Hans-Günther Kuhlmann. After training with 4. Unterseebootsflottille, U-166 was transferred to 10. Unterseebootsflottille for front-line service on 1 June 1942. The U-boat sailed on only two war patrols and sank four ships totalling 7,593 GRT GRT uses unsupported parameter (help).^[1] She was sunk on 30 July 1942, the only German submarine sunk in the Gulf of Mexico during World War II.^[3]

Service history

1st patrol

U-166 first sailed from Kiel to Kristiansand, Norway, on 30–31 May 1942.^[2] The U-boat sailed on her first combat patrol, from Kristiansand on 1 June 1942, around the British Isles, and arrived at Lorient, France, ten days later on 10 June.^[4]

2nd patrol

U-166 departed from Lorient on 17 June 1942, sailed across the Atlantic and into the Gulf of Mexico,^[5] and is credited with the following "kills":^[6]

• 11 July 1942: Carmen, 84 tons
• 13 July 1942: Oneida, 2,309 tons
• 16 July 1942: Gertrude, 16 tons
• 30 July 1942: Robert E. Lee, 5,184 tons

Fate

SS Robert E. Lee was under escort from the United States Navy patrol craft USS PC-566 approximately 45 miles (72 km) south of the Mississippi River Delta when she was torpedoed by U-166. The PC-566 immediately attacked the U-boat, and claimed to have sunk her with depth charges.

On 1 August 1942, a United States Coast Guard Widgeon amphibious aircraft, spotted a U-boat approximately 100 miles (160 km) off the coast of Houma, Louisiana. The aircraft attacked, and it appeared that the U-boat was hit in the attack. U-166 was reported missing in action on 30 July 1942, which coincided with the American aircraft's attack on "a U-Boat", leading to the aircraft being credited with the sinking of U-166. Both airmen were decorated for the action.^[6][7][8]

Wreckage located in 2001

However, in 2001, when the wreck of Robert E. Lee was located, in a depth of more than 5,000 feet (1,500 m) of water, the wreck of U-166 was also located, less than two miles from where it had attacked the Robert E. Lee. Upon investigation, it was discovered that another U-boat, U-171, also operating in the Gulf of Mexico, had reported coming under attack from an American aircraft on 1 August 1942, with little damage. Therefore, the credit for the sinking of U-166 should have gone to PC-566.^[7][9][10]

The site where U-166 lies, at 28°37′N 90°45′W / 28.617°N 90.750°W / 28.617; -90.750 has now been designated a war grave due to its crew of 52 being entombed there, and is protected from any future attempts to salvage it.^[11]