U-117's Successful Attack on America

U-117 and Crew

German mine-laying submarine U-117 arrived off the east coast of U.S. on 10 August 1918 and laid mines, which played a part in sinking of 13 Allied ships and vessels.  U-117, launched on 10 December 1917 with Kapitänleutnant Otto Droscher in command, was a UE-II series long-range minelaying U-boat. It was 267.5 feet long with a cruising speed of 14.7 knots on the surface and seven knots submerged. Its armament consisted of one deck gun, two mine tubes with a capacity to carry 42 mines, and four torpedo tubes. After departing Kiel, it set a course for North America to lay mines off the coast of the United States and to conduct undersea cruiser warfare. During the voyage across the Atlantic, heavy weather foiled its attempts to attack two lone steamers, two convoys, and a small cruiser.

 U-117 reached the American coast on 8 August 1918 and soon thereafter encountered a fishing fleet off the coast of Massachusetts. On 10 August, U-117 attacked and sunk nine fishing vessels with explosives and gunfire. On 12 August, it sighted the Norwegian steamer Sommerstadt and, after observing that the ship was armed, made a submerged attack that sank the steamer with a single torpedo. The following day, the U-boat made another submerged torpedo attack and hit the 7,127-ton American tanker Frederick R. Kellogg, bound from Tampico, Mexico, to Boston, Massachusetts, with 7,500 barrels of crude oil. The action occurred only 12 miles north of Barnegat Light, New Jersey, in shallow water, which ultimately enabled the ship to be salvaged.

Inspection by American Naval Officers After Surrender

Later that same day, U-117 began the minelaying phase of its operations by laying mines near Barnegat Light, New Jersey. Months later, that mine field claimed a victim when the Mallory Line steamship San Saba struck a mine and sank on 4 October 1918. On 14 August, U-117 took a break from minelaying operations to resume undersea cruiser warfare when it encountered the American schooner Dorothy B. Barrett. The U-boat brought its deck guns to bear and quickly sunk the sailing vessel. Shortly thereafter, however, the hunter became the hunted when an American seaplane and submarine chaser SC-71 forced the U-boat to seek refuge beneath the surface. The aircraft subjected U-117 to a brief barrage of bombs, and SC-71 attacked the U-boat with depth charges before losing track of the submarine.

The next day, 15 August 1918, U-117 resumed its minelaying operations, now off Delaware near the Fenwick Island Lightship. Later that year in September, mines laid claimed two victims, one damaged and the other sunk. The first victim was the battleship, USS Minnesota, which struck one of the mines on 29 September and suffered extensive damage.  Receiving minor damage to her starboard side, she returned to Philadelphia, Pennsylvania, and later returned to duty in March 1919.  The cargo ship Saetia later entered the same field on 9 November, struck a mine, and sank.

U-117 continued to move south on 15 August 1918. After laying a third minefield near Winter Quarters Shoal Lightship off Virginia, U-117 halted an American sailing vessel, the 1,613-ton Madrugada, and sank it with gunfire. Later that day, a patrolling American seaplane foiled a subsequent attempt by U-117 to stop another sailing ship, which escaped unharmed.

As a Prize of War, Washington Naval Yard

On 16 August 1918, U-117 resumed minelaying further south off of Cape Hatteras, North Carolina, but the approach of the 6,978-ton British steamer Mirlo interrupted its operation. Approaching the target submerged, U-117 fired a single torpedo that fatally damaged the steamer off Wimble Shoals. The ship's flammable cargo caught fire and nine of the 52 aboard lost their lives. A heroic rescue effort by U.S. Coast Guard personnel from the Chicamacomico Lifeboat Station under the command of Warrant Officer John Allen Midgett, Jr., brought the others safely ashore. Following the attack, U-117 again began laying mines, sowing its fourth and final field. At that point, a shortage of fuel forced the U-boat to begin making plans to return to Germany. U-117's next and final attack off Cape Hatteras was against the Norwegian bark Nordhav, which U-117 sank two days later farther offshore. U-117 then began its voyage back across the Atlantic to Germany.

After an unsuccessful attempt at a torpedo attack on a lone British steamer, War Ranee, on 5 September 1918, U-117 concentrated on making the final run toward Germany and safety. Three days later, U-117 was contacted over the wireless by the homeward-bound U-140 requesting a fuel replenishment rendezvous due to its critical fuel shortage. The two U-boats met on 12 and 13 September near the Faroe Islands, and U-140 took on about 5,000 gallons of diesel before continuing on toward Kiel. U-117 pulled into Kiel rather ignominiously on 22 September, having had to call upon a patrolling torpedo boat to tow it the last leg of its journey, having run out of fuel before making it back to port.

The Imperial German Navy recognized the success U-boats were having in United States waters, and planning for additional U-boat operations continued. Germany was in the process of sending three additional U-boats (U-155, U-152, and U-139) into U.S. waters when the war ended in November 1918. These U-boats were ordered to cancel their missions and surrender.

The armistice of 11 November 1918 ended hostilities and required Germany to turn over its U-boats to the Allies. U-117 surrendered ten days later in Harwich, England. Over the next few months, the U.S. Navy expressed an interest in acquiring several former German U-boats to serve as exhibits during a Victory Bond campaign.  U-117 became one of the six U-boats set aside for that purpose. In March 1919, American crews took over the U-boats and prepared for the trans-Atlantic crossing under their new task group name, the Ex-German Submarine Expeditionary Force.

After the war, U-117 was sunk during the Mitchell Bombing Tests in 1921 by the new lightweight bombs dropped by U.S. Navy F-5L aircraft. 

Adapted from: The Enemy in Home Waters, Office of National Marine Sanctuaries, NOAA