Rescue of the Squalus: The Sinking

At 7:30 a.m. on May 23, 1939, the Squalus left the Portsmouth Navy Yard located along the Piscataqua River in New Hampshire. It was underway for its 19th test dive under the command of Lieutenant Oliver Naquin. Before a submarine could qualify for the operational fleet, it was required to pass a series of trials. On this day, a crew of 59, five officers, 51 enlisted men and three civilian inspectors, were on board. The point of the day's test was to complete an emergency dive while cruising at 16 knots, diving to 50 feet within 60 seconds in order to avoid enemy attack. Once underwater, it was difficult for enemy aircraft to locate a submarine.

The spot chosen for the dive, just southeast of the Isles of Shoals, averaged a depth of 250 feet. As the submarine neared the designated point, the submarine's location and estimated submersion time were radioed to the Portsmouth Navy Yard. At 8:35 a.m., according to the deck log, Naquin order the crew to rig for dive (prepare to dive) and soon after gave the order to dive.