USS YP - 389 USS " YP - 389 " was a United States Navy yard patrol ( YP ) boat that served in World War II . The ship was built in 1941 as the fishing trawler " Cohasset " at the Fore River Shipyard in Quincy , Massachusetts for R . O ' Brien and Company . Acquired by the Navy on 6 February 1942 , she was originally designated as a coastal minesweeper , " AMc - 202 " , but was reclassified as a District Patrol Craft , " YP - 389 " , on 1 May 1942 . The ship was equipped with one dual purpose gun to protect the ship from enemy aircraft and surfaced submarine s and two machine gun s . YP - 389 was sunk by a German submarine on 19 June 1942 . Loss . Background . " U - 701 " , under Captain Lieutenant Horst Degen , was a very successful U - boat during the war . She was a Type VIIC submarine , displacing 1 , 070 tons , sent to American waters to destroy allied shipping . An American mine field had been laid off Cape Hatteras to deter U - boat attacks but after an American merchantman struck a mine and sank , the small 170 - ton naval trawler USS " YP - 389 " , under Lieutenant R . J . Phillips , was ordered to patrol the area and warn friendly ships of the mines . The trawler was armed with one 3 - inch gun , two machine gun s and four depth charge s . However the 3 - inch gun had a broken firing pin which could not be repaired before going out on patrol . The trawler also lacked degaussing equipment and sonar . This meant she had to be careful around the mines and could only attack a submarine with her machine guns and the depth charges if it was spotted visually . " U - 701 " first made contact with " YP - 389 " on or about 10 June 1942 but Captain Degen decided to leave the trawler alone so as to not alert other warships in the area . On 12 June , U - 701 mined the channel into Chesapeake Bay . For several days afterwards , it seemed as though every time " U - 701 " surfaced each night , the " YP - 389 " was on patrol nearby as if it was following the submarine . However , reports indicate that the Americans had no idea of the Germans ' presence until the morning of 19 June . On that day Degen came across the " YP - 389 " accidentally in misty conditions and attacked her to prevent the Americans from giving his position away . Battle . The battle began at about 2 : 45 am and occurred five miles off Diamond Shoals , the Germans used their 88 - milimeter deck gun and a 20 - milimeter anti - aircraft gun instead of torpedoes , because their target was so small , and when they opened fire the Americans were completely surprised . For over an hour and half the engagement was a chase . " U - 701 " pursued the American boat firing with both guns but it was difficult to hit the trawler in the darkness . It was mainly muzzle flashes from the machine guns on " YP - 389 " that gave the Germans something to aim at . Lieutenant Phillips thought that by releasing his depth charges in front of the chasing U - boat he might be able to damage it or at least scare the Germans off so for the last few moments of the engagement , the Americans dropped charges until being overwhelmed by gunfire . When the " YP - 389 " began to sink , Lieutenant Phillips ordered his men to abandon ship and the battle ended . Aftermath . Six American sailors were killed in action and eighteen others went into the water without lifeboats because lowering them meant being exposed to accurate enemy fire and the liferafts had all been shot away . The " U - 701 " was slightly damaged though no casualties were sustained . The fate of USS " YP - 389 " is most remembered by how such a small vessel could resist an attack by a much larger U - boat for so long and sustain so much damage before being destroyed . The battle was also one of the more significant surface engagements to have taken place in Torpedo Alley . " U - 701 " continued to scour the American East Coast for a few more weeks until being sunk by United States Army bomber s not far from Diamond Shoals . On 9 September 2009 , a research mission led by NOAA announced that the boat had been found and photographed off Cape Hatteras , North Carolina by the . The wreck rests in about of water in a region known as the " Graveyard of the Atlantic " , where several U . S . and British naval vessels , merchant ships , and German U - boats sunk during the Battle of the Atlantic .