Squalus sinking
The Squalus sinking refers to the tragic incident involving the U.S. Navy submarine SS-192, which occurred during a routine test dive on May 23, 1939. After reaching a depth of sixty feet, the submarine began to flood, leading to the deaths of twenty-six crew members. The vessel ultimately settled on the ocean floor at a depth of 243 feet. Efforts to rescue the crew were spearheaded by Commander Charles "Swede" Momsen, who utilized an innovative rescue chamber designed for such emergencies. This operation marked the first successful use of this technology in a rescue scenario, successfully bringing thirty-two survivors to safety after several challenging trips to the sunken submarine.
The salvage operation that followed was notably complex, as it involved recovering the Squalus from a greater depth than any submarine had been previously raised. The submarine was eventually salvaged and re-commissioned as the USS Sailfish, which went on to serve in nine World War II battles. The events surrounding the Squalus sinking significantly influenced future naval rescue procedures and diving techniques, particularly the use of helium-oxygen mixtures to manage the effects of deep-sea diving.
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Squalus sinking
The Event Sinking and subsequent salvage of a U.S. naval submarine off the coast of New England
Dates May 23 to September 13, 1939
Place Off the New Hampshire coast
After the USS Squalus sank, its surviving crew members were rescued, and the submarine was raised from the ocean floor. The successful rescue of the crew was largely the result of three diving innovations: the Momsen lung, the rescue chamber, and the gas mixture the divers used. After the Squalus was salvaged, changes were made to ensure that other submarines did not suffer the same fate.
Construction of the Squalus began on October 18, 1937, in the Portsmouth Navy Yard in New Hampshire. The Squalus was commissioned on March 1, 1939, under the command of Oliver Naquin. The submarine began a series of test dives near the Isles of Shoals and made its nineteenth on the morning of May 23. The dive was routine until the vessel reached a depth of sixty feet, when the engine rooms began to flood. Twenty-six men died when the after section of the submarine flooded. The Squalus came to rest at a depth of 243 feet, with the bow at an angle of eleven degrees. The Squalus sent up a marker buoy along with signal rockets. While waiting to be rescued, the crew put on their Momsen lungs, which they used as gas masks. The lung recycled exhaled air using an oblong rubber bag containing soda lime.
Commander Charles “Swede” Momsen, coinventor of the lung, led the rescue operation. Momsen and members of his Experimental Diving Unit and several Navy and Coast Guard ships were on the scene by midnight. The rescue ship, USS Falcon, arrived near dawn with the rescue chamber. Momsen had improved upon early diving-bell designs and had created the rescue chamber years earlier, but it had never been used in an actual rescue. The rescue chamber was made of steel, was pear-shaped and ten feet high, and had a maximum diameter of seven feet at the upper end. Two sailors steered the chamber to the sunken submarine along guidance wires to aid its descent and ascent. The bottom of the chamber attaches over the submarine’s escape hatch. The rescue chamber made four trips to the Squalus, bringing up seven men on the first trip, with additional men following to test the chamber’s capacity. The chamber held a maximum of eleven men: two crew and nine survivors. On the fourth trip, the retrieving wire snagged and began to break. The chamber was lowered back down until another wire could be connected. The ten men aboard, including Captain Naquin, were brought to the surface four and one-half hours later, shortly after midnight on May 25. All thirty-two sailors and one civilian who survived the sinking of the Squalus were successfully rescued.
The salvage of the Squalus began on May 25, and had three stages. The Squalus was at a greater depth than any other previously salvaged submarine, which complicated the process. To prevent the Squalus from rising at a sharp angle, the submarine was brought up a short distance using pontoons, then towed to higher ground. During the first attempt in July, the submarine rose out of control, broke free, and sank. The second attempt raised the Squalus seventy feet, and the third grounded it ninety-two feet below the surface. Two more attempts to raise the submarine were made before the Navy succeeded and towed the Squalus to Portsmouth on September 13. The Squalus was later re-commissioned the USS Sailfish.
Divers needed to attach the chamber’s guidance wires to the Squalus’s hatch, which presented another challenge for Momsen and his men. Breathing pure oxygen increases toxicity with depth, and nitrogen acts like laughing gas below two hundred feet and causes serious health problems. During the rescue, the divers began using various helium-oxygen mixtures and found they did not fog their minds like nitrogen did. The helium-oxygen mix needed a different decompression procedure, one that Momsen had been perfecting for two years. He considered the refining of this process during the rescue and salvage of the Squalus to be the operation’s greatest innovation.
Impact
The successful rescue of the Squalus crew, with the aid of Momsen’s lung and rescue chamber, led the Navy to attempt similar operations in the future. After its salvage, the Squalus was recommissioned as the USS Sailfish and was used in nine World War II battles.
Bibliography
Burrows, Nathaniel. Blow All Ballast: The Story of the USS Squalus. New York: Dodd Mead, 1940.
Ellsberg, Edward. Men Under the Sea. Reprint. New York: Dodd Mead, 1982.
Maas, Peter. The Rescuer. New York: Harper & Row, 1967.
‗‗‗‗‗‗‗‗. The Terrible Hours. New York: HarperCollins, 1999.
McCullough, Jonathon. A Tale of Two Subs. Boston: Grand Central, 2008.