On 25 March 1918, USS L-10 (SS-50) became the first U.S. submarine to be depth charged. Unfortunately, her attacker was a U.S. destroyer. L-10 and the destroyer had spotted each other early in the evening. “She passed nearly overhead,” wrote the sub’s commanding officer, Lieutenant James Van De Carr, “and dropped a depth bomb about 2000 yds beyond us. Fortunately she overran her distance. We could hear her stop and listen and then go ahead full speed.”

That might have been the end of it, but L-10 was so heavy that she was forced to use her bilge pumps for a few seconds to remove some of the water from the boat; the sound gave her away. “When a second depth bomb was let go I blew tanks and came to the surface for two reasons—one was that I did not want her [the destroyer] to waste depth bombs. We opened the hatch and let go a recognition signal simultaneously. …We let go two more smoke bombs and exchanged blinker signals.”

Once the danger was past, Van De Carr noted that “the behavior of the crew was, without exception, excellent, but after everything quieted down there were signs of nervousness and the men were a little unstrung. I decided to run completely submerged for the greater part of the next day in order to give all hands a good sleep and let them forget about it. Twenty-four hours after the incident they were again in good spirits and as keen as ever.”

He ended his report of the event by brushing it off as no big deal—just another day in the life of a Sailor. “The noise and concussion were about the same as is experienced in the fore top of a battleship when a turret is fired double barreled, just below.”

Men stacked four high on canvas fold-away bunks aboard an American L-boat in the European theater. From  Illustrated London News, 28 September, 1918.

Men stacked four high on canvas fold-away bunks aboard an American L-boat in the European theater. From Illustrated London News, 28 September, 1918.