At 243 feet below the Atlantic, the men in USS Squalus could hear ships moving somewhere above them.
They had survived the submarine’s sudden plunge to the bottom on May 23, 1939. The aft compartments were flooded. Twenty-six shipmates were gone. Thirty-three sailors and civilian technicians remained alive forward, breathing air that would not last forever.
On the surface, Navy divers were preparing a machine that had never rescued anyone from a sunken submarine. It looked like a steel bell with cables, ballast tanks, and just enough room for a handful of men. To work, it had to descend through cold water, find the submarine’s escape hatch, seal tightly against the hull, and climb back to daylight without losing its connection.
The device had been built because earlier submarine crews died waiting for help that technology could not yet provide. Now the McCann rescue chamber had one chance to prove that being trapped on the bottom did not have to mean being buried there.
A Test Dive Turns Into Disaster
Squalus was a new Sargo-class submarine built at Portsmouth Navy Yard. On the morning of May 23, she began another test dive off the Isles of Shoals near Portsmouth, New Hampshire. Fifty-nine people were aboard: 56 Navy personnel and three civilian technicians.
As the submarine submerged, a main engine air-induction valve failed to close. Seawater rushed into the aft portion of the boat, flooding the engine rooms, crew’s quarters, and after torpedo room. Quick action sealed watertight doors and saved the forward compartments, but the submarine settled on the seabed.
The depth was the problem. At 243 feet, an uncontrolled escape through the water carried enormous risk. Ordinary air diving at that depth also exposed rescuers to nitrogen narcosis and sharply limited working time. The survivors needed a way to move from one pressure hull to another without swimming for the surface.
Squalus released a telephone marker buoy and smoke signals. Her sister submarine USS Sculpin, sent to search the area, found the signs and established contact. The boat was located. Whether her living crew could be reached was another question.
A Rescue Machine Born From Earlier Losses
The answer had begun with two earlier tragedies. After USS S-51 sank in 1925 and USS S-4 went down in 1927, Navy officer Charles “Swede” Momsen pushed for practical ways to save submariners trapped below. He developed an individual escape breathing device known as the Momsen lung and helped conceive a rescue chamber that could carry men directly from a disabled submarine to the surface.
Commander Allan McCann completed major design revisions, and the machine became known as the McCann rescue chamber. Its lower section was designed to fit over a submarine escape hatch. Water could be forced out of the chamber’s skirt, creating a seal. Once pressure was equalized, the two hatches could open and submariners could climb into the chamber without exposing either vessel to the sea.
It was elegant on paper. But before Squalus, no U.S. Navy submarine crew had ever been brought up by one in an actual disaster.
USS Falcon Lowers the Chamber
The submarine rescue ship USS Falcon reached the scene with Momsen, McCann, Navy divers, and the chamber. Divers descended to clear obstructions and rig a guide cable to the forward escape hatch. They worked in darkness, cold, current, and pressure while the crews above tried to hold their ships over a target they could not see.
Late on the morning of May 24, Falcon lowered the chamber. It followed the cable down until its skirt settled over the submarine’s hatch. The operators pumped out the water, equalized pressure, and opened the passage.
For the first group inside Squalus, the sight overhead must have seemed impossible: a doorway in the ceiling leading to a steel elevator back to the living world.
The chamber rose with its first load of survivors. A second trip followed, then a third. Each cycle required the surface crew, chamber operators, divers, and trapped submariners to repeat a precise sequence while weather, machinery, and fatigue worked against them.
The Fourth Trip Nearly Stays Below
The last trip carried the final survivors, but trouble struck during the ascent. A cable fouled, leaving the chamber hanging below the surface with ten people aboard. For hours, the rescue itself was in danger of becoming another casualty.
Crews worked the problem until the chamber could be hauled upward. Shortly after midnight on May 25, the hatch opened and the final seven survivors emerged. Four chamber trips over roughly 14 hours had brought all 33 living men out of Squalus.
A fifth descent later checked the flooded aft torpedo room and confirmed there were no additional survivors. Coast Guard Cutter Harriet Lane carried rescued men back to the Portsmouth Navy Yard, freeing the Navy ships to remain over the wreck.
The Rescue That Changed the Rules
The Navy eventually raised Squalus after a difficult four-month salvage operation. Repaired and renamed USS Sailfish, the submarine returned to service and fought in World War II. The name changed, but the rescue remained a turning point.
Before May 1939, navies largely viewed survival inside a sunken submarine as a race toward an improvised escape. After Squalus, organized rescue became a real operating capability. The basic rescue-chamber concept remains in the Navy’s inventory because a simple pressure vessel, properly handled, is still reliable.
The story also carries a familiar lesson from other Fair Winds accounts, including the long search for USS Conestoga and the discovery of USS Indianapolis survivors: finding people at sea is only the beginning. Rescue demands equipment, preparation, and crews willing to keep solving the next problem when the first plan jams.
Thirty-three men came home because sailors and divers had learned from earlier losses, built something better, and trusted it when the Atlantic finally demanded proof. That is seamanship at its finest—memory turned into machinery, and machinery turned into a way home.
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