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Rescue of the Squalus Swede Momsen Submarines People Under the Sea Resources

Rescue of the Squalus: Recovery of the Squalus

View from Falcon of Navy Tugs towing USS Squalus.
View from Falcon of Navy Tugs towing USS Squalus (Milne Special Collections and Archives Department, University of New Hampshire Library, Durham, NH)

The second sinking of the Squalus killed no one, but it caused a mess of tangled cables, hoses and lines. Two pontoons remained attached, one was lost and the rest were taken ashore for repairs. By August 3, all the pontoons were found and being repaired.

The next time, there were six pontoons placed over the stern and four on the bow, with three on each end near 80 feet deep for control. The Squalus was raised successfully and towed on August 12. However, it unexpectedly got hung up on a small hilly area of the sea floor. This caused further delays and problems. Finally, the second ascent was accomplished by the 17th, and the vessel was towed to the sandy area. Once again, the Squalus bobbed to the surface unexpectedly and then settled to the bottom.

On August 30, bad weather forced the Falcon to buoy off all connections to the submarine and head for Portsmouth. Back on the scene on September 11, it took two days to prepare for the final lift. Once more, the Squalus rose out of control and sank. However, it then was brought to the surface successfully. The submarine was still deep enough that getting it past two shallow points in the river was done with difficulty. Since the initial and fatal sinking, 113 days had passed.

Thorough investigations of the submarine and its crew's actions ensued. It was officially concluded that a mechanical failure in the operating gear for the engine induction (air intake) valve caused the sinking. However, Momsen and others felt that an operator had accidentally opened the valve after the dive.

Technology had a critical impact on the salvage operation. At its outset, the divers had to use air (mainly nitrogen and oxygen), even though it was known from work by Momsen and his colleagues in the Experimental Diving Unit that a mixture of helium and oxygen was better. Equipment to employ the helium-oxygen mixture was to have been tested by Momsen that summer. During the salvage operation this equipment arrived on scene; however, problems with the diver's helmets occured. When new chemical absorbents for exhaled carbon dioxide were used, the helmets worked and were employed for over half of the operation. A new vacuum-tube phone system developed by RCA and a muffler for the sound of re-circulating helium also contributed greatly to the divers' performance. Three diving innovations developed by Momsen -- the lung, the rescue bell and the helium-oxygen mixture for divers -- all figured prominently in the rescue of the crew and recovery of the sunken Squalus.


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