 It is June 1964 and a US Navy deep sea vehicle is taking photographs of the sunken nuclear powered submarine. The boat is in pieces strewn across the seabed, some 119 nautical miles east of Cape Cod, Massachusetts. The area also serves as a gravesite for 129 dead personnel who were aboard when she lost communications. As the vehicle continues its survey of the boat, each photo hopes to better understand what had happened. The sub being photographed had sunk over a year earlier on the 10th of April 1963. She is called the USS fresher. Her loss was the first nuclear powered submarine to be sunk at sea and would be a turning point in submarine design and operation. The disaster would haunt the US Navy, requiring it to regularly monitor the wreckage for signs of contamination from its nuclear reactor. Due to the nature of the vessel, the decades of the disaster would be shrouded in mystery, but as always it would fall down to a failure of an overlooked component and inadequate training. Today I am looking at the USS fresher disaster. My name is John and welcome to Plainly Difficult. The Fastest and Quietest Our story begins in the late 1950s and the good old fun time known as the Cold War Nuclear Arms Race. Tensions were, well, tense between the east and west. Each portion of both sides' militaries were trying to outdo each other, bigger nuke, longer range missiles and the like, and the world under the waves was no different. Submarines were proven during both world wars to be a vital part of a country's ability to fight a war, and during the Cold War this was no different. They offered a brilliant way to put pressure on one's enemy. But they had traditionally always had one shortcoming, in that is how long they could stay submerged. Originally submarines had combustion engines or in some cases even coal fired power plants, which couldn't work underwater, well unless you wanted to suffocate your crew. As such they had to spend most of their time on the surface to charge their batteries and replenish air. Nuclear fission became the golden key to improving submarine endurance. You can run a nuclear reactor aboard a submarine without suffocating your crew, and with good enough shielding, you can even not irradiate them as well. So I'm really only just lightly touching on this to bring us to the central subject for this video, the USS fresher. She was a class of nuclear powered fast attack submarines and the lead vessel in her class. The class was built to find and attack other submarines. She was to be nuclear powered by an already established unit, the S5W reactor, used in the preceding Navy fast attack sub skipjack class. But the fresher would be designed around greater enemy sub detection. This would require a larger hull than her forerunner. To achieve her mission of long range detection, she had a large bow mounted sonar sphere. To allow for the central sphere, she had angled midship torpedoes. Her sail was reduced in size from previous subs to reduce drag to increase speed and she had isolated turbines on the submarine's hull in order to make her as quiet as possible. She had an improved hull, which allowed her to have an extended test depth of 1300 feet or 400 meters. The small sail, although handy for speed, giving the fresher top speed of 33 knots in fact, only allowed space for one periscope. She would be the fastest and quietest vessel of her type, making her a formidable foe for any Soviet submarine. Construction on the fresher began on the 15th of January 1958 at Portsmouth Naval Shipyard, with her keel being laid on the 28th of May 1958 being launched on the 9th of July 1960 and finally commissioned on the 3rd of August 1961. Following her commission, she would undergo extensive sea trials. As common with her first in class vessel, she was taken back to Portsmouth on the 16th of July 1962 for a scheduled six month post shakedown availability to examine systems and make repairs and corrections. It overran. Again, not particularly unheard of and running into nine months, she would eventually recertified and undocked on the 8th of April 1963. After recertifying, she would be required to undertake a number of dive trials, which would begin a day later on the 9th of April 1963. The dive trials. It is the morning of the 9th of April 1963 and the USS fresher is preparing to depart Portsmouth. Around 8am she passes Kittery Point. She heads out to sea to meet up with the recovery ship USS Skylar. The two vessels meet at 11am and the fresher begins her initial post overhaul trials. She conducted her first prim dive test and upon resurfacing she prepared for a second dive. She reached around half of her total dive depth. The fresher stayed underwater overnight and set up contact with the Skylar at around 6.30 in the morning on the 10th of April to continue the deep dive trials. Before her overhaul, the fresher had gone down to her maximum test dive around 40 times. Soon theory going down again shouldn't be too much of an issue. Because this was her first time to go down to a test depth post overhaul, her descent would be cautious by slowly diving deeper in circles under the Skylar. This helped keep in contact with the vessel above. She would stop at every 100 feet of depth to check the integrity of all systems. At 7.47 in the morning she was down to 400 feet. The Skylar received a report from the fresher's Lieutenant Commander John Wesley Harvey stating they were checking for leaks. All pretty normal for a test dive. At 9 minutes past 8 in the morning, the fresher reported again that she was now at 1.5 test depth. Then at 8.35 she was nearing her test depth at 300 feet from her target. At 9.12 in the morning, a test of the underwater telephone was completed and was satisfactory. However not long after this, the fresher reported via distorted message saying minor difficulties have positive up angle attempting to blow. Not long after another message came through but it was even more distorted with only the word 900 that could be made out. At 9.14 in the morning, the Skylar requested the fresher to transmit her course and bearing. A deafening silence returned. The Skylar continued to attempt to make contact with the now eerily quiet sub. At 9.17 in the morning, the silence was interrupted by garbled messages with the words test depth which was the only ones that could be made out. Seconds later, the Skylar heard with what sounded like as her commander would later describe a ship breaking up like a compartment collapsing. Although a worrying sign, hopes were held that the submarine was just undergoing communications issues. The Skylar rallied in the incident and by mid afternoon, 15 Navy ships were dispatched to the search area. By the evening with no recovery in sight, the families of the servicemen and small handful civilians aboard the fresher were informed of the boat's disappearance. The loss was made public and that all hope was lost by the 11th of April. On the 12th of April, President Kennedy ordered all federal government flags be flown at half mast for three days. However, the fresher still had to be found. The search would draw in multiple naval assets, including other submarines, submersibles and a whole raft of surface recovery ships. Deepsea cameras from the Naval Research Laboratory found some debris which would later be identified as from the fresher. The buffy scape, Triester was dispatched to the search area and began scouting the seabed in June 1963. However, shortcomings with some of the ships used for the search required an acquiring of a new vessel to handle the heavy deepsea equipment. The Mizar would be the answer to the issue and after fit out and equipping with a deepsea vehicle, strobe lights, cameras, sonar and a magnetometer were sent to the search for the fresher. This was around the 25th of June 1964 and within a few days the fresher's shattered hole was found on the seabed. The fresher's wreck was in five major sections, creating a debris field of roughly 1.4 million square feet. The Trieste II, the Trieste's successor, was sent to the incident site in September 1964 and managed to recover some of the debris. The photographs of the wreck, debris and operational history of the fresher would begin to build up a picture of the failure. This would lead on to an investigation which the result would remain classified for decades but thankfully have since come into the public realm. The cause. So being a cutting edge nuclear powered submarine, the US Navy weren't the most eager to release what caused its demise. However, due to it being a nuclear powered submarine, contamination readings had to be accessible to the public. This was because the reactor could potentially pollute the sea and regardless it would be picked up by one country or another eventually. But the cause is what we want to know. The mystery would sadly come down to a rather common explanation. A rather human one like that. But we will come back to that in a few minutes. The Navy's official investigation honed in on a likely instigating moment for the disaster being a failed brazed pipe joint rupturing in the engine room. Roughly around 9 minutes past 9 during the test dive. It's reasonable to assume that the crew would have tried to fix the rupture. Again, when going over the garbled transmissions, Commander Harvey would have ordered full speed, full rise on the fair weather planes and blowing the main ballast in order to surface. This was possibly the attempting to blow message heard by the skylock. Blowing the ballast tanks would involve purging them of water with compressed air. It was later found in experiments that moisture inside the tanks could cause ice to form on strainers installed in the valves. The ice built up to a point that the airflow was obstructed and thus reduced the submarine's ability to blow the ballast tanks and return to the surface. However, submarines don't solely rely on blowing ballast to reach the surface, especially at test depth. They normally pitch up and power to the surface. So what caused the lack of propulsion then? Well, the burst pipe in the engine room could have caused an electrical short which would have then caused the reactor to drop its control rods into the core. A safety feature called a scram. Scrams are actually good things as it protects the reactor, but not if you're filling up with water and need power. Operating procedures and use in the Navy at the time did not allow quick reactor start ups following a scram. Again, it makes sense as you know a scram is a very important safety system trip and you would need some time to investigate why the scram happened. But alas, this is not great when you're filling up with water and sinking. To add more issue, the reactors operation control officer, Lieutenant Raymond McCool wasn't aboard the fresher at the time and instead his role was being filled by Jim Henry, a sailor newly qualified from nuclear power school and is likely he would have followed the strict protocol and not have been able to restart the reactor. No power meant no ability to surface and now, heavier from the pipe rupture, the fresher's fate was sealed. But although the disaster was technical in nature, the human element was the ultimate cause, but not only with the crew, but the Navy as a whole. You see the fresher was kind of rushed to get on the Navy's roster and usually with rushed jobs staff training is the thing to suffer. You don't normally see the issues until something goes wrong. The technology was also still very new at the time with the world's first nuclear submarine, the Nautilus, only being just over a decade old when the fresher sank. The brazing failure was the initiating part to the disaster, it was also known as a problem on other vessels, but it was greatly underestimated the effect a failure could unleash. Sadly, all these seemingly minor issues worked out to be one costly one both in lives and equipment. But it would offer valuable lessons for the US Navy, although sadly it wouldn't be the last US nuclear submarine to be lost at sea. 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