On 24 June 1922, USS S-51 (SS-162), a fourth-group S-class submarine, was commissioned. She was homeported in New London, Connecticut, just up the coast from where she was built at the Lake Torpedo Boat Company in Bridgeport, Connecticut. S-51 operated normally and uneventfully until the night of 25 September 1925. What follows are excerpts from a history of S-51 written by the Ships’ Histories Section of the Naval History Division.

“It was a clear starlit night with bright moonlight…. S-51…had exchanged positions and routine information—this was the last communication anyone had from S-51. According to the survivors, the routine aboard the boat was normal….

“On the CITY OF ROME [a merchant steamer], …a lookout sighted a clear white light about five miles off the starboard beam at 2203; although he continued to watch this light and noticed that it seemed to be drawing closer, he never again mentioned it to the officer of the watch…. About three minutes later, the captain of the CITY OF ROME, John H. Diehl, a veteran of nearly forty years in the merchant marine, came to the bridge; he too saw the light to starboard and remarked upon it…, but then moved to the port side of the ship to allow his eyes to adjust to the dark…and remained there a crucial seventeen minutes. The light continued to draw nearer.

“At approximately 2223, Captain Diehl, his eyes now accustomed to the dark, returned to the starboard side of the bridge and looked at the light again; it seemed to be growing brighter, as if it were coming nearer, and he gave the order ‘Better starboard a little’ to give the other ship more passing room. Then a red light showed next to the white, and Diehl yelled ‘Port, hard aport, the fellow is showing a red light!’ simultaneously blowing a series of short blasts on the ship’s whistle to indicate danger. S-51 had apparently realized that the steamer was not going to yield right of way and had put her rudder hard right to avoid collision….

“…[W]ith a terrible grinding of metal, CITY OF ROME pierced S-51’s hull amidships, leaving a wound seven feet long and five to six feet high through which the sea poured in and began to fill the submarine. There was no panic belowdecks in the dying ship. The three survivors, thrown from their bunks by the force of collision, testified that as they waded through the rapidly deepening water in the compartments, they saw members of the crew helping each other through the hatches and attempting to secure the watertight doors….

“S-51 went to the bottom less than a minute after the collision; her clocks were stopped at 2225. Officers and crew other than the three survivors had apparently managed to get out, for only twenty-three bodies were recovered from the hulk of the ship. [There was a total of 36 men aboard.] The survivors testified that they had seen several others, the exact number impossible to determine, swimming around and calling for help.”

City of Rome lowered a lifeboat and rescued three survivors, but apparently did not realize that she had sunk a submarine and “that there might still be men alive in the sunken boat, trapped in an airtight compartment and waiting for rescue. When the survivors were questioned and Captain Diehl learned it had been a submarine, he didn’t think of going back to mark the place as clearly as possible so that rescue efforts could begin immediately.”

City of Rome notified her owners of the tragedy at 0010 on the morning of 26 September; the sub base in New London had no idea that anything was wrong until a message arrived via Western Union at 0120. Ships were immediately dispatched to the scene of the sinking, but the position supplied by the City of Rome was incorrect. S-51 was finally located, by a search plane whose crew noticed an oil slick and bubbles on the water’s surface, at 1045. “Ships converged on this spot, hoping that some of the crew might yet be alive within the hull. They hovered silently over the spot, listening intently, but could not hear any sound. The first divers reached the submarine [which lay in about 130 feet of water] at 1318, almost fifteen hours after the collision, but got no response to their tapping along the hull.” The twenty-three men remaining aboard the sunken sub were declared dead.

A court of inquiry convened by the Navy in the months after the disaster laid the blame for the sinking squarely on the shoulders of Captain Diehl, but he was later declared not guilty on civil charges of negligence and failure to stand by the sinking submarine when it was revealed “that the running lights on the S-class submarines…did not conform to the requirements of international law.” The Second District Court would later split the responsibility, blaming S-51’s running lights and City of Rome’s failure to take proper care to avoid collision for the sub’s loss.

S-51 was brought to the surface on 5 June 1926, nearly nine months after her sinking. There had been some hope of refitting her for further service, but the damage proved to be too great. The remains of the lost Sailors were removed and the hull was stripped. On 4 June 1930, the Borough Metal Company of Brooklyn, New York, purchased the hulk for $3,320.