Making headlines this week is the disappearance of the ARA San Juan, an Argentinian submarine that went missing on Wednesday, November 15th. The San Juan was coming home from a routine mission when it reported an electrical breakdown. Command instructed her to return to base immediately and cut her mission short. She was heard from once more, surfacing to report that the problem had been fixed and that she would submerge and proceed towards Mar del Plata Naval base. However, as of this writing, this was the last time anyone communication came from the San Juan. According to a US Navy press release, the US Navy is taking part in the search and rescue mission, sending two rescue systems from San Diego. The statement read that, “Three U.S. Air Force C-17 Globemaster III and one U.S. Air Force C-5 Galaxy aircraft will transport the first rescue system, the Submarine Rescue Chamber (SRC) and underwater intervention Remotely Operated Vehicle (ROV) from Miramar to Comodoro Rivadavia, Argentina.”[1] The Undersea Rescue Command constantly trains to be prepared for these rare occurrences when an undersea rescue may be needed. Training in both the U.S. and with foreign Navies, Cmdr. Mark Hazenberg, former Commanding Officer of the URC, says they operate to ensure that their systems can be loaded onto  airplanes within 24 hours of receiving a call. The SRC being deployed to the rescue mission is one of two in the U.S. Navy’s rescue command. Here is some information on how the SRC come to fruition and how it made one of the greatest submarine rescues in history.

In the early years of submarines, rescue was nearly impossible in cases of malfunctions or sinkings. By 1921, 825 men had died in submarine accidents. In 1925, Lieutenant Commander Charles “Swede” Momsen came up with the idea of a rescue chamber after the failed rescue attempt of the USS S-51(SS 162). Only three of the 37-man crew were able to escape before it sank. The men onboard were friends of Momsen. This event led Momsen to vow to find a way to recuse trapped crews. In 1926, Momsen proposed the idea of a diving bell, and development began in 1928. During the project, Momsen was reassigned[2] and Lieutenant Commander Allan McCann was put in charge of the project. The diving bell was introduced to the Navy in 1930 and was referred to as the McCann rescue chamber. The chamber worked by connecting directly over a submarine’s escape hatch. Once the pressurized air in the lower chamber was released, the chamber and submarine would be at equal pressure. The hatch could then be opened, and the trapped submariners could be brought into the bell and then to the surface. The diving bell was used in what many considered to be the most famous submarine rescue mission in 1939.

Figure 1A diver from the Falcon prepares to enter the water to help guide the rescue pod (right) to the USS Squalus. Courtesy of the Boston Public Library, Leslie Jones Collection.

On May 23, 1939, the USS Squalus was flooded and sank off the coast of New Hampshire while out on sea trials. Twenty-six men drowned when the aft compartments flooded but 33 of the men were able to find shelter in the forward compartments of the submarine. No submarine rescue had been successful past 20 feet. The Squalus was 240 feet beneath the ocean surface. Momsen was rushed to New Hampshire to help lead the rescue. The McCann diving bell was loaded onto the USS Falcon, a 187-foot minesweeper stationed in New London, and made the 200-mile trip up the coast. Lt. Oliver Naquin ordered the release of a marker buoy that was attached to a cable and had a telephone in it. On the side of the buoy was lettering that said, “Submarine sunk here. Telephone inside.” The Sculpin (Squalus sister ship), sent out to search for the distressed submarine, came across smoke signals and found the buoy. A lieutenant explained the issue to Sculpin’s commander. As soon as he put Naquin on the line with the commander, the cable snapped. However, the communication was enough for them to know that there were survivors on board and to begin the rescue. Rescuers were able to decipher some Morse code from the crew, gaining knowledge that 33 men were alive in the forward compartments. Momsen planned to bring them up in four trips of seven, eight, nine and nine, though he wasn’t certain that nine would fit. The diving bell was 10 feet high and seven feet wide. Two sailors would make the trip down to rescue the Squalus’s crew. Torpedoman’s mate John Mihalowski and Gunner’s mate Walter Harman were loaded into the upper chamber of the bell along with blankets, flashlights, pea soup, sandwiches, and soda lime powder. The two were sent down, attached to the Squalus and opened the hatch. The first seven men who the commander had deemed the weakest were loaded onto the bell and began towards to the surface. For the second trip, the order was for eight survivors to be taken up. However, Chief Machinist’s mate William Badders was afraid of the dangerously changing weather and decided to bring up more. While Momsen thought the bell looked heavy as she came up, he told Badders, “You brought out too many men on this trip, but do it again.”[3] The third trip went just like the first two. The fourth and last trip took 4 ½ hours. The wire attached to the bell broke and attempts to apply a new one became too perilous. Momsen decided that the only way to bring the survivors home was to manually lift the 21,600-pound bell. Six men on the Falcon took hold of the wire and began to pull. Each time finding it too heavy, the men on the bell were ordered to blow the ballast tanks for 15 seconds to control the buoyancy. After the third attempt, the chamber began to move. Thirty-nine hours after its sinking, all 33 survivors were safely at the surface.

Figure 2USS Squalus survivors aboard the USS Falcon. Photo: U.S. Navy

According to the Undersea Museum, of the 19 U.S. submarines that accidentally sunk, nine involved at least some of the crew surviving. After the rescue of the Squalus crew, the idea that submarine rescue at sea was improbable diminished. The Navy continues to develop its rescue programs today. The two rescue chambers in today’s Navy are advanced versions of the original McCann chamber and can be used in up to 850 feet of water. Along with the SRC being deployed to Argentina, the Navy is also sending the Pressurized Rescue Module, which is similar the bell in concept. However, while the bell is lowered by a tethered chord from the mother ship, the PRM is operated remotely. It can descend to 2,000 feet and carry up to 18 people, including two attendants. Submarine service is much safer today than it was in the past. However, each Navy trains their sailors to be prepared for the worst. Our hearts are with those in Argentina and with our own sailors who are helping search for the missing submarine and its crew. If found in time, we know the SRC, the modern counterpart of the McCann rescue chamber, will be there to perform as trained and provide a way out that at one time was viewed as unachievable.

Figure 3 A rescue chamber on display at the Submarine Force Library and Museum.



[2] Momsen’s reassignement lead to his most famous invention, the Momsen Lung.