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The mysterious story about the sinking of U 166

The story about the sinking of U 166 started, when on 01 August 1942 the crew of a Grumman amphibious a/c of the Type J4F “Widgeon” of the USCG 212nd Squadron strafed a German U-boat which proceeded at surface off the Mississippi estuary, to report eventually a successful sinking of it. USCG Pilot Henry Clark White and his crew mate George Henderson Boggs assured to have sunk an 80 meters long U-boat. After the war, they were accredited the successful sinking of U 166 in the Gulf of Mexico, since this U-boat under the command of Oberleutnant zur See (= Lieutenant) Hans-Günther Kuhlmann had been reported missing in the area until then.

Oberleutnant zur See Hans-Günther Kuhlmann - Kommandant von U 166
Oberleutnant zur See (=Lieutenant) Hans-Günther Kuhlmann – Commander of U 166

However, the story about U 166 turned out to be somewhat differently. In Spring 2001, almost 60 years after its sinking a remote controlled underwater search vehicle discovered during sea bed surveys for the oil exploration companies of BP and Shell for the installation of a pipeline the wreckage of passenger liner Robert E. Lee and just 4 miles away the wreckage of a German U-boat. This could be identified soon as U 166. Now, the position of German U-boat wreckage was more than 200 kilometers different to the location where it had been sunk allegedly by an aircraft of the US Coast Guard (USCG).

What has really happened?

U 166 was a long-range type IXC U-boat, which had left is base at Lorient in German occupied France for its second combat patrol. The U-boat had been tasked to execute a special mission: Mining of the Mississippi estuary. While departing through the Bay of Biscay U 166 reported on 20 June 1942 to have been flood lighted by an aircraft to then being bombed, however, no damage was received.

On 10 July 1942 U 166 reported: “09.46 hrs – convoy sighted at Naval quadrant DO 7185, two vessels and two destroyers, bearing 170°, 14 nautical miles, fired six torpedoes all missed. – U 166”.

Apparently this convoy was a formation of fast moving vessels, whose pursuit would have caused too much fuel consumption for the U-boat. The six torpedo failures were another reason to abandon any further attempt to engage, as the mission to the Gulf of Mexico was not to be endangered. Kuhlmann transmitted his decision, also in order to guide other U-boats to the fast convoy.

The next day U 166 met the 84 GRT sailing vessel Carmen from the Domenican Republic off the southeast corner of the island. Kuhlmann stopped the vessel and made sure the crew to enter their lifeboat. The vessel had loaded 2.000 sacks of maize and a few pieces of luxury woods. U 166 sank the sailing vessel by means of its 10,5 cm gun. One sailors of the crew made it to shore later, one sailor died.

After U 166 had crossed the Mona Passage it sank two days later the US 2.309 GRT vessel Oneida nearby the Acklins Islands north of the Dominican Republic.

The further voyage of U 166 led through the Windward Passage into the Gulf of Mexico. On 16 July 1942 the German U-boat stopped the US 16 GRT fishing vessel Gertrude not far away from Havanna, the capital of Cuba. The three men crew entered their lifeboat and rowed towards the Cuban coast eventually reaching it. Meanwhile Kuhlmann ordered to sink the fishing vessel, which carried several tons of onions for Havanna, by means of high explosive shells

Now, the U-boat was heading for its original target: New Orleans and the Mississippi estuary. During the night of 25 July 1942 U 166 laid nine TMC mines off South Pass into the estuary, just 600 meters before the mole heads of Port Eads. Since no vessel really passed this mine barrier, it remained undetected until the end of the war. Only after having studied German records the Americans gained knowledge of it and cleared the mines. On 27 July 1942 U 166 reported back to the B.d.U (= U-boat High Command): “Have executed the special mission during the night 24 to 25 July – U 166“.

Hans-Günther Kuhlmann auf der Brücke seines Bootes U 580
Hans-Günther Kuhlmann on the bridge of U 580

Although the U-boat had carried out its main mission Kuhlmann decided to operate further off the Mississippi estuary. His plan seemed to pay off, when he sighted on 30 July 1942 the American 5.184 GRT passenger liner Robert E. Lee through his periscope, about 70 nm off the Mississippi mouth. The liner under Master William C. Heath was enroute from Trinidad via Key West to New Orleans. The crew comprised some 130 men and 6 gunners. Additionally they had 268 passengers on board, most of them survivors from merchant vessels sunk, among them the survivors of the Norwegian 10.000 GRT oiler Andrea Brøvig sunk by U 128 on 23 June1942, and the Panama 10.000 GRT oiler Stanvac Palembang sunk by U 203 on 11 July 1942. The liner also carried piece-goods. About 16.30 hrs Kuhlmann ordered to fire a torpedo. When the torpedo approaching was detected by the look out of the liner, it was much too late. The torpedo detonated right in the engine room and the Robert E.Lee immediately listed, to eventually sink within 15 minutes. Most of the crew and the passenger could be rescued by Naval tugs and other guard ships that were called in straight away. Sadly, 10 crew and 15 passengers did not survive.

Probably, Oberleutant zur See Hans-Günther Kuhlmann was to allow his crew to observe the passenger liner sinking from the conning tower of the U-boat. Therefore, he gave the fateful order “Surface!”

This turned out to be a grave mistake. Because there was the 300 to USN submarine chaser USS PC-566 under the command of LtCdr H.C. Claudius and 64 men on board escorting the Robert E. Lee, which Kuhlmann apparently had not spotted through the periscope yet. When U 166 realized the presence of the submarine chaser, it was much too late. Though the U-boat managed to execute an emergency dive it nevertheless did not reachsafe water depth soon enough. The first salvo of PC-566´s depth charges hit the forward part of the U-boat, which was ripped of its main hull. Both parts of the U-boat sank to the sea bed, almost 1.500 meters in the Mississippi underwater canyon. Not far from that the Robert E. Lee came to the bottom of the ocean as well. None of the 52 strong crew of U 166 had any chance to survive.

In Germany one was awaiting news from U 166 in vain. When nothing came in, the U-boat and its crew was declared “Missing in action”. As told above, the successful sinking of U 166 was accredited to the crew of the aircraft of USCG 212 Squadron. Both, pilot White and aircrewman Boggs hade stated corresponding to have attacked a U-boat while submerging fast, and to have sunk the U-boat by means of their 150 kg bomb. Crewman Bogg added that he had spotted the hit firmly and also the sinking of the U-boat. Moreover, the USCG aircraft had circled the position of the sinking for more than one hour, also oil spells had been discovered, which hardened the crew´s claim to have successfully sunk a U-boat.

p306_1_01But, if it wasn´t U 166, what U-boat had been attacked by the USCG aircraft?

In fact, it had been U 171 under the command of Kapitänleutnant (= Lieutenant Commander) Günter Pfeffer that also patrolled in the Gulf of Mexico at that time. The U-boat did not experience significant damage caused by the attack of the USCG aircraft, allowing it to continue its operation as scheduled. Nevertheless, the days of U 171 were counted.

On 09 October 1942, at the end of a very long combat patrol, U 171 had reached it rendevouz point for the

escort back into home base when suddenly a magnetic mine at 40 meters water depth ignited right under the U-boat. Within seconds U 171 started to sink taking some 22 sailors along into the deep, only 40 men could be rescued by German Naval units. Sadly, at the end of this almost four months long combat patrol the U-boat´s degaussing had become ineffective.

After his report about the attack on a German U-boat the Commanding Officer of the USN submarine chaser PC-566 was reprimanded for not having carried out his attack with sufficient thoroughness. Notwithstanding, the credit for a successful sinking of a U-boat in the area remained unchanged some 59 years with the USCG aircraft. Only in 2001 the truth came to light through the discovery of the Robert E.Lee and U 166 almost side by side. Unfortunately, this was too late to rehabilitate LtCdr Claudius – he had died in 1981.

Text: Hans-Joachim Röll and German U-boat Museum, picutures: German U-boat Museum

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