The USS Squalus - The US Navy's most successful failure. In 1939, the USS Squalus (SS-192) was lost during a dive test. But hope was not lost. This story, as with others, tells the tale of the horror of sinking in a sub, but this time, there were survivors. This time, rescue was within reach. This is the story of how 32 men survived the sinking of the Squalus and how the Navy came together to save not only these men, but the sub itself.

The USS Squalus (SS-192) of the Sargo-class, built at the Portsmouth Navy Yard, in New Hampshire, was put to sea on March 1, 1939. With a surface displacement of 1, 450 tons, and 2, 350 tons submerged, she was of a standard size for her day. 310' 6" long and a speed of 20 knots (surfaced) and 8.75 knots submerged, she had a small compliment of 55 men. Before the days of Nuclear-powered submarines, they were diesel-powered. But diesels had many drawbacks. They could only be used on the surface, because the engines required air for the combustion and the engines generated toxic exhaust. Because of this limitation, they used electric motors when submerged. Part of the function of the diesels were their requirement for fresh-air for the combustion. Not enough air could be circulated or generated for the both the crew and the engines, so the engines were fed fresh-air via an air-induction pipe on deck. This pipe circulated air throughout the sub when surfaced, both for the crew and supplied a direct feed to the engines. When submerging, an induction valve would slide over the intake to seal the pipe and the electric motors would be engaged for underwater manoeuvres. This feature also included a manual back up.

After fitting out at Portsmouth, the submarine began a series of test dives, as is the procedure of all new submarines, off the Isle of Shoals. After 18 successful dives, on May 23, 1939, the Squalus left the Portsmouth Navy Yard for the Piscataqua River in New Hampshire. Underway for the 19th dive, she was under the command of Lieutenant Oliver Naquin. Not yet qualified for fleet operations, she still had a number of trials to pass, such as deep dives; emergency blowing of the air tanks; etc. On this day, for this particular dive, she carried 115 crew, and three civilians on board. This test was for an emergency dive at 16 knots, down to 50 feet in 60 seconds. The area that was chosen for the dive was fairly shallow, just southeast of the Isle of Shoals, with a depth of 250'. As she neared her designated coordinates, she radioed in her position to the Portsmouth Nay Yard. At 8:35AM, Naquin ordered the crew to rig for dive, and soon, ordered her full dive. The status of this valve and others are monitored via control board in the engine room, known as the "Christmas tree". This board consisted of red and green lights in rows showing whether the valves were open or closed. Red meant open and green meant closed. When all the lights were green, it was safe to submerge the ship.

On this particular dive the diving officer for Squalus was Lt. William Doyle. He was in charge of diving the Squalus from the control room. After the commander of the Squalus ordered the dive, the crew began the procedure by flooding the ballast tanks with water. As she went under, the diesels were shut down; the induction valve was closed and the electric motors were activated. Before the ballast tanks were fully flooded and the boat completely submerged, the control board was checked for 'all green'. All the lights were green but as a precaution, extra air was pumped into the submarine's hull from a pressurized cylinder, thereby increasing the air pressure inside the sub enhancing the sub's airtight seal. As the boat dropped past 50 feet, the call came to the control room that the engine rooms were flooding. Water was coming in through the induction valve and was flooding the aft spaces of the submarine. It took only a few minutes to sink to the bottom, without a list with the bow raised above the stern by 11 degrees. She settled at 243 feet, with the temperatures dropping rapidly inside the sub since she had no power for heat and the outside water temperature was only about -30C.

The first problem facing the crew was isolating the incoming water to the aft-quarters of the boat. For the most part, it had been accomplished as the sub sank. But as she settled, there were many oil and water leaks spraying in the drier compartments, but these were quickly closed off. Only some small lanterns were used for lighting, creating a surreal environment. The next priority and perhaps must disturbing for those left alive was to determine who wasn't with them any longer. 59 people set sail with Squalus that morning. By 9AM, only 33 were still alive. 23 were in the control room and 10 in the forward torpedo room. Only small hand-held lanterns provided dim lighting, probably adding to the grim environment. One can only imagine what they must have been thinking, surrounded by all that water The reality of the situation must have hit hard when they realised that those missing were most likely dead, drowned in the engine rooms and the aft battery room. There was still hope that some may have secured themselves in a sealed compartment, but it was a glimmer of hope, the reality of the situation being the most prevalent in their minds. Five people moved forward from the control room to the torpedo room. The control room was warm but wet from valves spraying water and oil, and some water washing in from the aft sections of the sub when she went down. However, it was dry but very cold and getting colder in the forward sections of the sub. Saltwater was leaking into the forward battery section. This section separated the control room from the torpedo room and if the saltwater mixed with the battery acid, chlorine gas could form, poisoning the air, or the batteries could short and start a fire. These potential dangers rendered this room un-useable, and since the control room had a foot of oil and water at its aft bulkhead, and the room just below it had a slow leak, the control room was not in favour for much use itself.

A telephone buoy was released manually from the Squalus, via the communication cable. Fortunately, it reached the surface but to no avail. No one was looking for Squalus yet. The telephone buoy also didn't last long as the tension on the cable soon became too strong and it snapped soon after surfacing. After six hours on the ocean floor, rockets were released from the sub at regular intervals, and as luck would have it, the Squalus' sister-sub, the Sculpin, was in the vicinity of Squalus' operation zone. When fleet-command could not raise the Squalus, the Sculpin was ordered to search for her. By chance, a lookout on the Sculpin noticed the yellow smoke from the Squalus' sixth rocket.

Inside the Squalus, conversation was kept to a minimum to conserve oxygen. Many of the survivors were wet from exposure to the rushing water and were cold, both from the water and the decreasing internal temperatures inside the sub. Since she had no functioning power supply, heat was a quickly fading commodity. By noon, the men were sharing canned fruit. The increasingly toxic air made the men drowsy. The use of a carbon-dioxide absorbent agent was first used by 2pm. By 6pm, the men had beans, fruit and tomatoes for diner. Pressurized oxygen cans were used to replenish the air supply inside the sub on regular intervals.

During the afternoon, two other ships arrived on-site, the USS Falcon and the USS Penacook, whose propeller sounds could be heard by the crew of the Squalus. An oscillator was used to generate Morse Code transmissions to the Squalus which responded hammering on the hull. Unfortunately, due to the depth of the sub, the sounds were barely audible and hardly understood due to the intermittent loss of some of the sounds. By midnight, the water in the pump room below the survivors in the control room had risen to two feet in depth.

On May 23, rescuers rushed to the site of the Squalus' sinking. Charles Momsen, two doctors and a diver left Washington DC, by seaplane and landed at Portsmouth at 7:30pm. By 11:30PM, they were on-site. By midnight, Penacook and had succeeded in grappling Squalus somewhere on her hull. Falcon had the Momsen Diving Bell, air pressure systems, a decompression chamber for divers and their gear. Back onshore, wives, girlfriends and families of the crew of the Squalus, awaited news. Messages received from the sub indicating 'condition satisfactory but cold', left much hope among those ashore. The media was all over the story. One group of reporters chattered a boat for a 15-hour journey to the scene and back. When they returned with the facts that some of the crew had perished in the sinking, it was a devastating blow to the people ashore. At twice the surface-atmospheric pressure, there were three options to rescuing the survivors. The first idea explored was to pump in air into the sub to float the Squalus to the surface. But it was put aside as it wasn't yet known what sent her to the bottom to begin with. The second was to have the men come to the surface using 'Momsen Lungs'. But the current depth of the sub was greater than that which the lungs had been tested at. It was finally decided upon to use the diving bell to retrieve the men.

By the morning of May 24, the weather was rough, with choppy seas, squalls and near-zero visibility. The Falcon had to drop four anchors to secure herself over the Squalus. After four hours of rough seas, another anchor line was passed to the Falcon to help stabilize her. To familiarize themselves with the structure of the Squalus, Momsen and his divers moved to the Sculpin, sister-ship of the Squalus. To maximize time and to hold morale up, Momsen selected to use divers from both his team and that of the Falcon. The grappling hook that had caught the sub, hooked only 10 feet away from the rescue hatch the diving bell would use, and it took the first diver on the sub 22 minutes to hook a guideline for the diving bell. When the crew in the Squalus heard the footsteps of the diver outside the hull, they responded by happily banging on the hull walls. Momsen had vetoed an idea to make five trips down to the Squalus for fear that the more trips made, the greater the risk involved. His intent was to bring up seven men on the first trip then eight on the second and finally two trips with nine. With the diving bell linked to the Falcon via a cable, to lift it from the bottom, two air hoses and an electrical cable for the lights and phone. The diving bell would be going down with two operators for the motors, ballast, air pressure and communications. Upon arriving at the sub, the crew of the diving bell delivered hot coffee and food while they loaded seven men. At that time, the exact list of who was lost was exchanged with the crew of the diving bell. At the time of the descent of the diving bell, the survivors inside the Squalus were aware of the efforts being made above the surface, and seven men were selected from among the survivors. They donned their Momsen Lungs (contained oxygen masks) and made their way through the chlorine-contaminated forward battery room.

The second descent to the sub took an hour plus 45mins attached to the sub to exchange supplies and load the men and a half hour to ascend to the surface. Momsen was concerned that taking eight men at a time was too much for the diving bell's systems and decided to make a fifth trip after taking fewer men the next trip. The third trip went as the previous others, without any difficulty. However, on the fourth trip, the reel taking up the cable as the diving bell rose, fouled up. A diver that was sent down to disentangle the cables was unable to do so. It was decided to decrease buoyancy to allow the diving bell to settle on the bottom to conserve energy. The recovery of the diving bell proved to be quite frustrating. A diver was sent down to attach a cable to lift the bell but due to rough surface seas and the tension on the cable, he was unable to attach the cable. A second diver was sent down but also failed. It was found that only a minor strand was left on the original cable and therefore the bell would be unable to ascend on its own. Inside the chamber, Momsen decided to attempt to float the chamber to the surface by adjusting the buoyancy of the bell, while the sailors aboard the Falcon would pull in the frayed cable slowly as the chamber came up. 38 minutes after midnight, May 25th, the last survivors surfaced. It had been 39 hours since the Squalus sank.

Being one of the first of her class, recovering Squalus was of utmost importance to determine why she sank before others of her kind were put to sea. The challenge that presented itself to the US Navy was unlike any other encountered previously: how to get a 1, 450-ton, 310' long submarine from 243 feet underwater, to the port 15 miles away. Because the valve that sent Squalus to the bottom was still open, pumping out the water was not possible. It was not known if the remainder of the sub flooded after the crew were rescued. It was decided to attach pontoons filled with air to lift the sub. Three stages were planned for the lift. The first, would have the sub raised 80 feet off the seabed and towed a mile and a half till it grounded again in shallower water. Then lift it another 80 feet and tow it another 5 miles until a solid, sandy bottom could be found. Then lift it until it was at 40 feet, to tow it up the Piscataqua River at high tide to the Portsmouth Navy Yard.

For salvaging of the Squalus, Momsen had at his disposal 58 divers. Due to her extreme depth, each dive allowed the divers only 15 minutes each on the bottom. Efficiency had to be of the utmost priority. Difficulties were common but were finally surpassed when a line was run under the sub, in the sand. The first of the greater challenges was the stern. Buried in 20 feet of mud, it presented a tactical challenge rarely encountered up until then. A plan to blast a path under the stern by blowing pressurized water through a hose and then through a pipe. June 5 saw the beginning of the stern-recovery operation. 58 dives had been made up until then. 10 days of failed attempts showed that this plan was not feasible. The plan was improved upon by using 40 of curved pipes under the stern.

By June 29, hoses were run to all the ballast tanks on the sub and 360 tons of diesel fuel had been pumped off of the sub. But bad weather struck a severe blow to the operation. The tug Sagamore was blown off -station, rupturing all but 30 cables and ropes to the Squalus. Unfortunately, the main cable under the Squalus had been damaged and a diver had to make a night dive to install a clamp on the hose. By July 4, the 32x13 pontoons were on site. With a lift of 8 tons, it was believed 7 of them should provide enough lift to free Squalus. They were attached by July 13, five tied to the stern and two to the bow. Three other pontoons were set at 80feet for control of the ascent. The plan was that when those three pontoons reached the surface, they would cease to provide lift and the sub would be ready to be towed in-land.

On that day, air was pumped into the pontoons and one ballast tank aboard the sub. A second tank was filled with air since the first did not provide enough lift on its own. Too much air was pumped into the second tank and the sub suddenly freed itself and rushed to the surface out of control. Squalus shot out over 30' into the air. Unexpected and out of control, the rescue crew surrounding the area barely escaped injury as the sub splashed down and bobbed around uncontrollably. Squalus slowly sank back to the bottom, leaving a confusing mess of tangled ropes and cables on the surface, along with a lot of racked nerves. Two of the pontoons were still attached to the sub when she went down again, one was lost and the rest were so severely damaged they had to be taken back ashore for repairs. By August 3rd, all pontoons had been found and repaired and a new plan was put in place to attempt a second recovery of the sub.

The next attempt saw six pontoons placed over the stern and four over the bow, with three more on each end at a depth of 80 feet, for a controlled ascent. This time it worked and Squalus was towed in-land one and a half miles on August 12. However the success was short-lived as she got hung up on a small hilly area of the sea floor. By August 17th, the sub had been raised from the hill and towed to the original sandy area. But for reasons unknown, once again the Squalus came rushing up out of the water and sank back down to the bottom. Fortunately, this time, it was supposed to rest on the seafloor at this point. On August 30th, bad weather damaged Falcon and she had to sever all her connections to the Squalus and return to Portsmouth. It was not until September 11th, that she returned, in which it took two more days to prepare for the lift. Again, as if some demon possessed her, Squalus shot out of the water out of control and sank again. But on the 2nd attempt, she was brought up under control and readied for the final leg of her journey to Portsmouth. Still, with two more points of shallow water to contend with, she wasn't home yet. It had been 113 days since the sinking. After returning to port, and being dry-docked, the bodies of the dead were removed. After the sub had 'dried out', her equipment was inspected and was found to be undamaged with the exception of the electrical equipment.

By May 15, 1940, she was recomissioned as the USS Sailfish. President Roosevelt suggested the name after seeing pictures of the bow bobbing on the surface when she was raised the first time. In 1941 the Sailfish was assigned to the Atlantic fleet out of the Philippines. Four of the original crew were assigned to the sub. In 1945, the Navy decommissioned the Sailfish. On Veteran's Day in 1946 the conning tower and a section of the bridge were established as a memorial in Portsmouth, dedicated to the accomplishments of the submarine service.