Greatest Submarine Rescue in History

by Mike Crowe

USS Falcon rescue crew listening to communications from their diver working on the sunken sub in May, 1939. The Falcon was the rescue and recovery vessel anchored over the submarine Squalus which had 59 crewmen aboard.

In the spring of 1939, Lt. Oliver Naquin had come to the Portsmouth Navy Yard in Kittery, Maine to take command of a new submarine. Not unlike John Paul Jones, who had come to Kittery 164 years earlier to oversee the construction and outfitting of the Ranger, he was there for the completion and sea trials of the Navy’s newest fleet type submarine, the Squalus. Like others in the 59 man crew, Naquin had moved his wife and children to Ports­mouth for the new assignment.

At the time, the Squalus was state-of-the-art engineering. She In the spring of 1939, Lt. Oliver Naquin had come to the Ports­mouth Navy Yard in Kittery, Maine to take command of a new submarine. Not unlike John Paul Jones, who had come to Kittery 164 years earlier to oversee the construction and outfitting of the Ranger, he was there for the completion and sea trials of the Navy’s newest fleet type submarine, the Squalus. Like others in the 59 man crew, Naquin had moved his wife and children to Ports­mouth for the new assignment.

At the time, the Squalus was state-of-the-art engineering. She was 310 feet long, with a 27 foot beam and displacement of 1,450 tons. Power was from the two-stroke Fairbanks-Morse, 1600 hp diesel engine. This was an opposed piston engine; each of the 10 cylinders contained two pistons. The combustion space was formed by the two pistons arriving near the center simultaneously. There were two engine rooms with two engines in each.

The batteries, Exide Company Sargo type, had 126 cells each. Each cell weighed 2,000 lbs. There were two batteries in the forward battery and two in the after battery. The four 1600 hp engines gave her a 16 knot surface speed. Submerged, battery power produced 9 knots.

But engineering and a long list of built-in precautions, were not enough to dispel the fears of family members and some crew, that came from the illogic of being in the ocean in a heavy metal object that was effectively designed to sink. When a sub went down, the crew was all but presumed lost.

On the morning of Tuesday, May 23, 1939 the Squalus left its mooring in a cove just below Portsmouth for a test dive five miles southeast of the Isle of Shoals, 15 miles from the coast. In addition to tests of equipment that had been a problem on earlier runs, they wanted to meet the “60 seconds to periscope depth” goal. Approaching the dive point their position was radioed to the Navy yard.

At about 8:40 a.m., with the momentum from maximum surface speed, they switched from diesel to battery power and began the decent. Bow and stern planes were angled for a hard dive. When they reached 28 feet, there was a brief hesitation as they became fully submerged. As they passed the 50 foot mark, Naquin went to the periscope. He leaned forward to the eyepiece. As he did he heard a strange rumbling, and in an instant a crewman on the battle phone reported that the rear engine room was flooding.

The Squalus continued to dive, shorts in the battery room created a lightning storm of blue-white arcs cutting off power. Water in the engine room dragged down the aft end of the sub. The planes were shifted to the rise position, water was blown out of some ballast tanks. The sub slowly stop­ped and began rising, bow up. But it was short lived; at 80 feet, with water everywhere, sloshing and hissing from a dozen places, the lights went out – then chaos and uncontrolled descent.

Word reached the control room that the high induction valves that feed air to the diesel engines while running on the surface, were open on the dive. The 30-inch openings for the valves flooded the engine room and the aft torpedo room. The rumble heard had been air being forced through passages by the surge of incoming water. Aft bulkheads were closed as the sub sank. Five minutes after beginning the dive it came to rest at a 10 degree angle on the bottom, aft ballast tanks in the mud at 243 feet.

The bow of the Squalus rising out of control after being raised 243 feet by lift pontoons 15 miles off Kittery in May of 1939. A pontoon with air lines can be seen in the background. The small boat carrying Capt. Momsen is to the left. Seconds later it went down driving the aft section 20 feet into the muddy bottom in a tangle of lift cables and gear.

After no contact with the Squalus for three hours, the Navy yard sent out the sub Sculpin. When nothing was sighted by noon the sub was assumed down. But the Squalus’ position had been misread at Kittery and the Sculpin was five miles from the actual location. The Squalus had been sending up rocket flares at intervals. At 12:40 p.m. the sixth rocket was finally seen from the distant bridge of the Sculpin. A marker buoy sent up by the Squalus was found and brought aboard the Sculpin, in it was a phone line to the sub. The Squalus made phone contact, but within minutes rising swells broke the line and the Squalus was lost again.

On the bottom, in 33 degree water, the crew pounded signals on the hull. Huddled in the damp and cold of the control room were 18 men, 15 more in the forward torpedo room. Grouped standing together, sitting alone on the tile deck, wrapped in wet blankets or already soaked from escaping the rush of sea water, they tried to listen past the erratic hissing of valves under enormous pressure for the sound of rescue ships. In the dark, except for dim light from hand held lanterns, they breathed the foul air, knowing that at any time it might be mixed with chlorine gas that could seep in from the forward battery.

The certainty of death for submariners in either combat or equipment failure-related sinkings became the driving force of one submariner, captain and inventor, Charles “Swede” Momsen. It was Momsen who, after the sinking and loss of the crew aboard the submarine S4 in 1929, developed rescue equipment, and tested it at the risk of his own life. He was the only man on the planet on May 23, 1939 considered capable of attempting a rescue at 243 feet.

Momsen had developed the “Momsen lung” which contained air and functioned as a lung while worn like a life jacket. It was successfully used at shallower depths. But it was a pressurized diving chamber, which Momsen developed that he brought to the Squalus. He had experimented with it in deep muddy rivers and offshore, but never in an actual submarine emergency.

Momsen was called in and a rescue effort initiated. Living in Virginia, he went directly to a flight to Portsmouth aboard a Navy pontoon plane. Newspaper reporters from many cities were also en route by planes, trains and cars. Those from the nine Boston papers were first on the scene. Arriving at the Navy yard, Momsen made the decision to attempt to use the bell to reach the sub. It was coming in on the minesweeper Falcon from New London, Connecticut and arrived at dawn on the 24th.

Divers were needed to attach guide cables to the sub’s hatch for the chamber to track on. Diving to 243 feet was practically unheard of in 1939. This was before scuba gear; diving was done wearing a heavy spherical metal helmet and bulky heavy rubber suit. Air was supplied by a hose from a pump on the dive boat. Working on the bottom in knee deep mud beyond the known depth at the time, the divers were winging it. Overexertion might cause grogginess that could make a diver open his pressure valve too far, blowing up his suit and sending him to the surface like a rocket, crippling or killing the strangely contorted victim. That was the disaster of choice over “the squeeze.” Helmet pressure had to be nearly equal to that of the surrounding sea. If a diver fell suddenly, like off a sub deck, pressure per square inch went up fast. If the diver did not make an immediate adjustment, the pressure squeeze began in his feet and ran up his body until his body was squeezed into his helmet.

The Falcon was anchored over the sub. A Coast Guard cutter carried a load of reporters to the site. Planes circled overhead. With only a few minutes at a time on the bottom, the divers set up the down haul for the chamber.

A cut-away drawing of the diving bell or chamber like the one used to rescue the crew of the Squalus. The chamber had existed, but Charles Momsen developed gear and techniques for its successful use in deep diving submarine rescue.

Thirty-three of the Squalus crew were accounted for, the others were believed trapped or drowned in the aft torpedo room. The plan was to lower the pressurized bell with two men aboard, attach it to the ring around the sub’s hatch, open the hatch and bring up the crew, seven at a time. A plan easily proposed from this point in time, in 1939 it had never been done. Momsen had developed the chamber for this purpose, as well as techniques for pressurizing and controlling the open-bottomed chamber in deep dives.

Momsen had led an experimental deep diving unit in Washington, D.C. He was aware of the stories of men drowned on the high seas who had sunk deep then rose to the surface where their bodies “blew up” from air expanding deep inside them. One of his innovations was to use a mix of helium with oxygen for deep diving. Divers had been using air and were subject to the bends. The air we breath is oxygen and nitrogen. Under the pressures, that greatly increase with water depth, oxygen becomes toxic. At two hundred feet nitrogen is forced into the blood stream and body tissue. It can produce nitrogen narcosis, a druglike state where thinking is muddled. If a diver rises too fast, the nitrogen is released from his tissue, entering the joints, causing the bends. The joints in great pain are forced to bend, causing injury and possibly death. Momsen replaced nitrogen with nontoxic helium and measured oxygen intake according to depth. The result was the ability to work past 300 feet. Heliox later made deep dives with scuba gear possible.

The bell went down, just before 10 a.m. About forty minutes later it was attached, the hatch opened and crewmen were seen staring up at the two men in the chamber. Hot coffee and sandwiches were handed down and seven crewmen climbed out. Forty minutes later they were aboard the Falcon. Three more trips were made. On the fourth trip, with light fading, the bell was sent down and the last of the survivors brought on. As it came up the chamber stopped rising at 150 feet. The crane tugged at it, but nothing helped. Momsen sent down a diver, who found a length of cable tangled and freed it. But he also found all but one strand of the cable broken. After three divers attempted to fix it, Momsen decided to pull the bell up by hand with nine crewmen. Pressure in the bell was raised and ballast reduced in a delicate balance to maximize buoyancy while the cable was hauled in over the side. At midnight, 39 hours after the test dive had begun, all account­ed for crewmen were aboard the Falcon.

Now it was time to open the aft torpedo room hatch. The next morning, May 25th, with the bell cable replaced, the fifth decent began. The descent cable was moved from the forward to the aft hatch. In the process of doing this the diver succumbed to the pressure and was brought up. Another diver went down, but was brought up immediately. The third diver completed the task and the bell was lowered. The hatch was opened, but the aft torpedo room was filled with water right up to the hatch opening. The loss of the other crewmen was certain, but for the first time, death in a sunken submarine was not.

What is considered the greatest submarine rescue in history was completed. But the Squalus had to be raised to determine what sank her. The plans to build many more Squalus-type subs were riding on the answers to this question. There were reports being spread around that it was sabotage. Press interviews of crewmen reported that the high induction valves had definitely been closed and the control board lights supported that conclusion. These reports fed the conspiracy fever. Earlier reports of mechanical difficulties with those intake valves seemed to get second billing.

The rescue effort was a highly focused singular task with a narrow window of opportunity. Raising the Squalus was a monumental engineering feat reliant on experimental technologies and an open-ended schedule. The plan included the use of five 32’x15’ barrel shaped pontoons to lift the sub. There were also lift lines, miles of cable, teams of divers working at record depths, as well as a half dozen ships to work from and to supply the operation.

When the dozens of lines to two levels of pontoons were in place, the lifting began. When the sub broke free of the mud it started to rise, but the aft was hung up. The bow lifted, then the aft freed up and the sub headed for the surface, bow first. Momsen was orchestrating the lift in a motorized whaleboat from the middle of the ring of ships at the site. He saw the sea boil around him and suddenly the Squalus bow burst straight up through the surface. It shot up to 30 feet, seemed to hang there and just as suddenly as it appeared, dropped below the surface headed back to the bottom.

Momsen rearranged the positions of the pontoons for the second lift. Weeks were spent stripping the tangle from the Squalus. It took 58 dives to get rid of just three of the lines. It was not until September 13th that they were ready. It went as planned, and the conning tower of the Squalus finally broke the surface again. One hundred and thirteen days after it went down and 640 dives to get her up, she was under tow to the Navy yard. Although the control panel light indicated it was closed, the air intake valve was found to be open and the cause of the sinking. All but one of the crewmen’s bodies were found in the aft torpedo room. The missing crewman was believed to have crawled to a hatch that might have been forced open by sudden air pressure and reclosed by water when the air escaped. The sub was recommissioned on May 15, 1940 and renamed the Sailfin. Four of the Squalus survivors sailed on the Sailfin. h