The following day, the U-boat made another submerged torpedo attack and hit the 7,127 gross register tons (GRT) American tanker Frederic R. Kellogg, bound from Tampico, Mexico, to Boston, Massachusetts, with 7,500 barrels of crude oil.

The action occurred only 12 mi (19 km) north of Barnegat Light, New Jersey; however, Frederic R. Kellogg was disabled in such shallow water that the Americans were able to salvage her.

The Naval Overseas Transportation Service cargo ship Saetia entered the same field on 9 November, struck a mine, and sank.

Later that day – still 14 August – the submarine moved farther south and, after laying a third minefield near Winter Quarter Shoals Lightship, halted an American sailing vessel, the 1,613 GRT Madrugada, and sank her with gunfire.

On 16 August 1918, U-117 resumed her mining operations, this time off Cape Hatteras, North Carolina, but the approach of the 6,978 GRT British steamer Mirlo interrupted her labors.

On 17 August 1918, she stopped a Norwegian sailing ship, the 2,846 GRT Nordhav, out of Buenos Aires, Argentina, bound for New York laden with linseed.

The next day, U-117 caught sight of the Norwegian freighter Bergsdalen, steaming in ballast from La Pallice, France, to Baltimore, Maryland, and sank her quarry with a single torpedo.

Three days later, on 30 August, she encountered her final two victims, when she stopped the 136 GRT British fishing trawlers Elsie Porter and Potentate and sank both with explosive charges.

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-in toward the Skagerrak and safety.

Over the ensuing weeks, the United States Navy expressed an interest in acquiring several former German submarines to serve as exhibits during a Victory Bond campaign.

After a hectic time preparing for sea, U-117 stood down the English Channel from Harwich on 3 April, in company with the submarine tender Sumner, and UB-88, UB-148, and UC-97.

There, she remained – partially dismantled – until taken out to sea in June 1921, to serve as a target for aerial bombing tests conducted by the Navy and Army.