Rescue of the Squalus: Recovery of the 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.