Thirty-three men were alive in the forward compartments of USS Squalus. Behind them, the submarine’s flooded sections held twenty-six people who had not survived.
The boat lay in 243 feet of water off New Hampshire after a test dive on May 23, 1939. Bringing the survivors up would require more than locating the wreck.
The USS Squalus rescue became a demonstration of a chamber designed for exactly the situation the men now occupied: a damaged submarine containing people who could not simply swim to the surface.
USS Squalus: A dive that did not end normally
Water entered through the main engine-air induction system. Flooding spread through the aft spaces, while the surviving men remained isolated forward.
The submarine rescue ship Falcon arrived at the scene, supported by divers and personnel who had spent years developing ways to reach a stricken submarine.
Commander Charles “Swede” Momsen’s later lecture described the wreck’s slight list and stern-down position. He also described the difficulty and danger of sending divers to that depth using the equipment available in 1939.
The survivors were therefore separated from rescue by both water and a technical problem. Air remained inside the compartment. Getting people from that air into a safe ascent required a controlled connection to the outside.
Four trips to the forward hatch
The McCann rescue chamber was lowered to the submarine. In four trips on May 24, it brought the thirty-three survivors out.
A later run to the aft torpedo-room hatch found the space flooded and no signs of life. The successful rescue forward did not change the loss in the other part of the boat.
The submarine was eventually raised, repaired and renamed Sailfish. The more immediate result was that thirty-three men who had been trapped on the seabed returned alive.
It is tempting to tell this only as a story of an invention proving itself. The crew’s position makes it more personal than that. Their survival depended on a sequence of preparations made before the accident: research, trained divers, a rescue ship and a chamber that could be brought to their hatch.
The men could not shorten the depth by knowing help was above them. The rescuers had to cross it repeatedly, then return to a second hatch where the outcome was already different.
Squalus held both endings at once: living people waiting inside the same wreck as people the rescue chamber could no longer save.
Sources and reporting
Researched reporting: an original narrative based on the published records linked below.
