About 2:55 p. m. the same day the fog lifted and two shots were heard from a point 1,500 yards distant. Upon observation a submarine was seen firing with both guns at the Navajo. The first shot dropped 50 yards short on the starboard beam; the second one went over the ship. The Navajo was swung, bringing the submarine about three points on the starboard quarter, and opened fire with her after-gun.
The submarine fired about 40 shots during the engagement, which lasted 40 minutes, one of which hit the Navajo underneath the port counter. This shell exploded before hitting the ship and displaced some of the plates, causing the Navajo to leak.
The Navajo in return fired 27 shots, the last two of which were hits. The twenty-seventh shot struck the submarine just forward of the conning tower where the ammunition hoist was located, causing an explosion on board the submarine which was plainly heard on the Navajo. The men who were on deck at the guns and had not jumped overboard ran aft. The submarine then canted forward at almost 40 degrees and the propeller could be seen lashing the air. Nobody was seen coming up through the conning tower and jumping into the sea, nor were any survivors seen.
The armed guard commander concluded: "It is my opinion that the submarine was sunk."
The men of the Borinquen were also convinced that they sank a U-boat which they encountered in latitude 56°-32' north, longitude 10°-46' west, June 4, 1917. Chief Gunner's Mate T. J. Beerman reported:
Submarine was laying to when first sighted. We think she was receiving news from her headquarters. After-gun could not bear on her then and while the trainer was training gun around to bear, loader fired pistol to wake up men in the shelter house, at the same time hoisting our colors. Pointer turned on lights and dropped sights from 500 yards to 100 yards. As soon as after-gun could bear she opened fire. I did not see the first shot, but petty officer said it went just over top of submarine's conning tower. I saw the second shot hit, exploding and carrying away the conning tower. She was about three points abaft the port beam.
The ship putting stern to submarine, the third shot was fired about astern. I saw it hit and explode. After second shot the submarine seemed to be stopped and lay in trough of sea at the mercy of the gun. The last seen of her she was going down on swell, listed to port, with her bow sticking in air and her stern down. She was going down in an upright position.
Struck by a torpedo, the Norlina, after "abandon ship" was ordered and its men had taken to the boats, manned its guns and when the U-boat reappeared, put the enemy out of business. This engagement, which took place June 4, 1917, in latitude 56°-32' north, longitude 10°-46' west, was one of the queerest of war incidents.
At 6:30 p. m., a man on the forward gun platform shouted, "Torpedo!" As the ship turned the torpedo hit just abaft the beam, glanced off aft around the stern, and sank. The first mate sounded the "abandon ship," signal and the crew made for the lifeboats. Lieutenant Commander J. Foster, captain of the vessel, three of his mates and the armed guard commander remained aboard. Inspecting the vessel, they found it in no danger of sinking, and called all hands to return. Chief Boatswain's Mate O. J. Gullickson, commanding the armed guard, reported:
As boats came alongside, a periscope was sighted off the starboard beam. Guns were manned, commenced firing from forward gun, range 2,000 yards. In the meantime the captain had gotten the engineers below and we got under way, heading toward periscope. Continued firing from both guns, all shots coming very close to the periscope, submarine changing speed.