0:00:02 > 0:00:06In May 1939, the crew of the submarine USS Squalus
0:00:06 > 0:00:10was struck by disaster, deep below the surface of the Atlantic Ocean.
0:00:18 > 0:00:23They were trapped on the ocean floor with their air running out and no means of escape...
0:00:24 > 0:00:29the latest victims of what the US Navy dubbed the coffin service.
0:00:42 > 0:00:48Their fate depended on one man, naval inventor Charles "Swede" Momsen.
0:00:52 > 0:00:55Momsen's attempt to rescue the men of the Squalus would become one
0:00:55 > 0:00:59of the most celebrated rescue missions in maritime history.
0:01:01 > 0:01:06It kick-started a whole new area of underwater technology and revolutionised our understanding
0:01:06 > 0:01:11of what can be achieved in the dangerous and alien world deep beneath the waves.
0:01:28 > 0:01:35On May 23rd 1939, a prototype American submarine was preparing for a routine dive.
0:01:38 > 0:01:44The exercise was taking place 25 kilometres off New Hampshire on the east coast of America.
0:01:46 > 0:01:48- Are you ready for diving, crew? - Aye, sir.
0:01:52 > 0:01:56This was the USS Squalus' 19th test dive -
0:01:56 > 0:01:59a timed crash dive for use in emergencies.
0:02:04 > 0:02:09- First officer, prepare to dive the boat!- Prepare to dive the boat!
0:02:09 > 0:02:11Under the command of Lt Oliver Naquin...
0:02:11 > 0:02:18- Dive the boat.- Dive the boat. - The Squalus had to dive to periscope depth - 15 metres - in 60 seconds.
0:02:19 > 0:02:27- Mark.- That's one, two and three, OK? - A series of levers closed the valves that fed air to the diesel engines.
0:02:27 > 0:02:32Green signalled that the sub was watertight.
0:02:34 > 0:02:36At 7.40am, the dive began.
0:02:48 > 0:02:50Mark.
0:02:50 > 0:02:5262 seconds.
0:02:52 > 0:02:53Well done, gentlemen.
0:02:56 > 0:03:03It seemed a textbook dive, but within seconds it went disastrously wrong.
0:03:04 > 0:03:05SCREAMING
0:03:21 > 0:03:26Unbelievably, water was pouring through the main induction valves in the rear of the sub.
0:03:33 > 0:03:36FRANTIC SHOUTING
0:03:38 > 0:03:40Main valve's not working!
0:03:47 > 0:03:49We've hit bottom, sir.
0:03:55 > 0:04:00Somehow, despite the all-clear on the control panel, a valve was open
0:04:00 > 0:04:03and hundreds of tonnes of water were pouring in the sub.
0:04:03 > 0:04:07They lost control of her and she went down to the bottom.
0:04:07 > 0:04:10Now I'm a professional diver and I know what it's like
0:04:10 > 0:04:14when things go wrong, but I've benefited from immediate backup.
0:04:14 > 0:04:16These men were on their own.
0:04:16 > 0:04:18What was going to happen to them?
0:04:18 > 0:04:23Bearing in mind that in the previous 20 years worldwide,
0:04:23 > 0:04:2822 subs had been lost, along with the lives of over a thousand men.
0:04:28 > 0:04:31They didn't call it the coffin service for nothing.
0:04:35 > 0:04:41In the 1930s, submariners like the crew of the Squalus were taking their lives in their hands.
0:04:42 > 0:04:47Underwater technology was in its infancy and, in the history
0:04:47 > 0:04:52of submarines, no crew had ever been rescued from the ocean depths.
0:04:52 > 0:04:58The disaster of the Squalus would become a pivotal event that would change underwater safety forever.
0:05:00 > 0:05:04Even today, flooding is a danger that terrifies every submariner
0:05:04 > 0:05:09and recruits are trained how to react to any breach of their boat.
0:05:10 > 0:05:14In this simulator, the sheer force of a wall of water pouring through
0:05:14 > 0:05:19at 14 lbs-per-square-inch pressure is a terrifying experience.
0:05:27 > 0:05:29This is really hard work
0:05:29 > 0:05:31but of course I knew it was going to happen.
0:05:31 > 0:05:36For those men on the Squalus it would just have been a sudden, tremendous shock.
0:05:36 > 0:05:39Freezing cold water under high pressure.
0:05:39 > 0:05:42We're here at the surface, but even at periscope depth
0:05:42 > 0:05:45it's twice what the pressure is at the surface
0:05:45 > 0:05:51and the water just comes pouring in under ever increasing pressure.
0:05:51 > 0:05:54It wasn't long, despite their best efforts, before
0:05:54 > 0:05:57the men in the rear of the sub were completely overwhelmed.
0:06:00 > 0:06:07Within a few minutes, water was flooding from the rear to the front of the sub.
0:06:07 > 0:06:10As men struggled desperately forwards, the crew who had already
0:06:10 > 0:06:14made it into the control room faced an agonising decision.
0:06:16 > 0:06:20Either wait for their crew mates to come through and risk the whole sub flooding,
0:06:20 > 0:06:26or shut the watertight bulkhead doors and condemn them to certain death.
0:06:31 > 0:06:34They were ordered to seal the control room.
0:06:39 > 0:06:40SCREAMING
0:06:43 > 0:06:4726 men died in those first few minutes.
0:06:47 > 0:06:5433 survivors were entombed in what was now a watery coffin stranded on the bottom of the ocean.
0:07:04 > 0:07:0989-year-old Carl Bryson is the last living survivor from the Squalus.
0:07:10 > 0:07:15Carl joined the Navy as a teenager in 1936.
0:07:15 > 0:07:22By the summer of 1939, he was a 22-year-old machinist's mate serving aboard his second sub.
0:07:24 > 0:07:28He was in the forward battery when the Squalus went down.
0:07:33 > 0:07:39I never really thought about dying there, that would never have crossed my mind.
0:07:39 > 0:07:43When the water first started to come in, I didn't have time to think about
0:07:43 > 0:07:46anything except how to shut the water off.
0:07:46 > 0:07:48Everybody said, "What did you think?"
0:07:48 > 0:07:52I didn't think anything except how can we stop the water from coming in?
0:07:52 > 0:07:57This is the main induction valve - all the water would have come in here.
0:07:57 > 0:08:01- Massive volumes of water pouring in this.- Tremendous volume.
0:08:01 > 0:08:04And it went into both engine rooms.
0:08:09 > 0:08:14The crew in the forward section of the Squalus had survived the initial flooding,
0:08:14 > 0:08:20but now they were trapped with only enough air to survive for 48 hours...
0:08:20 > 0:08:25and a new danger was already upon them.
0:08:25 > 0:08:28Water was seeping into the forward battery compartment,
0:08:28 > 0:08:33threatening to short-circuit the huge batteries that powered the sub's electric motors.
0:08:33 > 0:08:36This is the forward battery, of course.
0:08:36 > 0:08:38This is the battery hatch.
0:08:38 > 0:08:44Luke opened the hatch and the acid was bubbling and the caps
0:08:44 > 0:08:51on the batteries were coming out, so the battery was overheating, we were pulling several thousand amps.
0:08:55 > 0:09:01As the batteries heated to a critical level, the chief electrician shut off her power.
0:09:09 > 0:09:12Another 30 seconds, probably, and we would have had a battery explosion.
0:09:20 > 0:09:24Nobody in the battery compartment would have stayed alive,
0:09:24 > 0:09:28the people in the control room would have been lost...
0:09:29 > 0:09:36somebody may just possibly have made it out of the forward torpedo room. I doubt it.
0:09:37 > 0:09:41With no power, there was no heating,
0:09:41 > 0:09:46no light and no hope of raising the sub.
0:09:46 > 0:09:50For Captain Naquin, it was time to make a harrowing assessment.
0:09:52 > 0:09:54Take a roll call. Yes, Sir.
0:09:56 > 0:09:57- Bryson!- Aye, sir.
0:09:57 > 0:10:00CALLS NAMES IN ALPHABETICAL ORDER
0:10:05 > 0:10:07Aft torpedo, do you copy?
0:10:07 > 0:10:10FAINT BUZZING
0:10:12 > 0:10:15Aft torpedo, do you copy?
0:10:15 > 0:10:18FAINT BUZZING
0:10:18 > 0:10:21Forward battery, do you copy?
0:10:21 > 0:10:23FAINT BUZZING
0:10:25 > 0:10:27Forward torpedo, do you copy?
0:10:27 > 0:10:30FAINT BUZZING
0:10:33 > 0:10:40With almost half her crew dead, a dwindling air supply, no power and
0:10:40 > 0:10:44no way of reaching the surface, this was a submariner's worst nightmare.
0:10:51 > 0:10:55Ever since the sinking of the Lusitania in World War I
0:10:55 > 0:11:01by a German U-boat, naval commanders knew they needed submarines.
0:11:01 > 0:11:08But the early models produced on both sides of the Atlantic, some of which were even powered by steam,
0:11:08 > 0:11:14were often a greater danger to their own crews than enemy shipping - they were steel death traps.
0:11:17 > 0:11:23Submarine design had moved on by the '30s, but despite the image portrayed in recruitment films,
0:11:23 > 0:11:29service under water was still cramped, noisy and highly dangerous.
0:11:29 > 0:11:35The men who served in them had a reputation as mavericks, kind of naval pirates.
0:11:35 > 0:11:40It's said the admirals of the day saw these crews as expendable.
0:11:40 > 0:11:44But despite the dangers, there was pressing reasons
0:11:44 > 0:11:49why young Americans of the 1930s signed up for the coffin service.
0:11:49 > 0:11:57'Millions of Americans, men, women and children wait in the cold on bread lines, in soup kitchens.'
0:11:57 > 0:12:01The Great Depression of 1929 threw America into turmoil.
0:12:01 > 0:12:06By 1932, the economy had virtually collapsed.
0:12:06 > 0:12:11'..Construction virtually ceases, mills and factories shut down,
0:12:11 > 0:12:14'railroads come to a virtual standstill.'
0:12:14 > 0:12:16There were 15 million unemployed
0:12:16 > 0:12:21and the wealth of the average American had dropped to the level of 25 years earlier.
0:12:21 > 0:12:23'..The ranks of the unemployed are to soar...'
0:12:23 > 0:12:25But the submarine service provided an escape
0:12:25 > 0:12:28from the hunger and uncertainty of the times.
0:12:33 > 0:12:38While the rest of the US was gripped by poverty and unemployment, young sailors were guaranteed
0:12:38 > 0:12:43roofs over their heads, three square meals a day and a weekly pay packet.
0:12:43 > 0:12:47'Here's one place where mess call means all hands on deck to stow cargo
0:12:47 > 0:12:51and there's plenty of room in the hold for seconds.
0:12:51 > 0:12:55'After this man stows his gear in his new locker, he hangs up a picture of
0:12:55 > 0:13:01'his old schoolteacher and makes himself at home in the comfortable barrack accommodation.'
0:13:01 > 0:13:07Submariners got an added bonus - an extra 25 or 30 a month in their pay.
0:13:07 > 0:13:12It was called submarine pay but this extra cash was actually danger money.
0:13:12 > 0:13:17The submarine service was still the riskiest branch of the Navy.
0:13:24 > 0:13:30For the crew of the stricken Squalus trapped on the ocean floor, things were going from bad to worse.
0:13:30 > 0:13:32MEN SHOUT
0:13:32 > 0:13:37In the forward battery of the sub, seawater was reacting with acid
0:13:37 > 0:13:41to produce poisonous chlorine gas, which was beginning to spread.
0:13:46 > 0:13:51We weren't to the point of gasping or anything like that, but, er...
0:13:51 > 0:13:56we could smell chlorine gas and that certainly was an indicator we wanted out.
0:14:00 > 0:14:02But there was no way out.
0:14:04 > 0:14:10The stricken sub was on the ocean floor at a depth of 74 metres.
0:14:10 > 0:14:16Radio communication was impossible that far down and the last message to base had been garbled.
0:14:16 > 0:14:22The sub was actually eight kilometres from where base understood her to be.
0:14:22 > 0:14:24Well and truly lost.
0:14:26 > 0:14:33The crew released a marker buoy and some rocket flares, but the chances of rescue were remote.
0:14:33 > 0:14:38Trapped in America's newest submarine, all the men could do was pray.
0:14:42 > 0:14:50In the '30s and '40s, subs built here at Portsmouth naval yard were at the forefront of submarine design
0:14:50 > 0:14:57and 20,000 men built virtually half of America's submarine fleet for World War II.
0:14:57 > 0:15:03Squalus was at the cutting edge of these developments and yet still the sea took her.
0:15:03 > 0:15:08Now the race was on to find her, but even if she was found,
0:15:08 > 0:15:11the big question remained - could those men be saved?
0:15:13 > 0:15:20The answer to that lay with one man, Lieutenant Charles Momsen, nicknamed "Swede" Momsen.
0:15:22 > 0:15:27In 1925, 14 years before the Squalus disaster,
0:15:27 > 0:15:33Momsen was a sub commander and was badly shaken by the tragic sinking of his vessel's sister submarine.
0:15:35 > 0:15:40Stranded on the bottom of the ocean, several of Momsen's friends lost their lives
0:15:40 > 0:15:43while the Navy stood by helplessly.
0:15:46 > 0:15:49Momsen was determined things had to change.
0:15:49 > 0:15:52Submarines had to become safer.
0:15:57 > 0:16:01Helen Hart Momsen is Charles Momsen's granddaughter.
0:16:01 > 0:16:07Swede Momsen is her hero and she knows his story inside out.
0:16:07 > 0:16:11He had lost friends, people he went to the naval academy with had
0:16:11 > 0:16:17been lost in submarine disasters, people that he actually knew.
0:16:17 > 0:16:22One of the men, when they opened the submarine after they salvaged it,
0:16:22 > 0:16:29his fingers were all torn to stubs because he had tried to open the hatch, which would have been
0:16:29 > 0:16:38impossible even without the water on top of it, but I guess people just do terrible things in their final hours
0:16:38 > 0:16:45and he was just overwhelmed because, at first he thought, "Well, it wouldn't be so bad -
0:16:45 > 0:16:49"they probably just went to sleep, they probably just died a simple death."
0:16:49 > 0:16:52But when they opened the hatch and he realised the agony they had
0:16:52 > 0:16:58gone through, he said, "It can't be this way, it just can't be this way."
0:16:58 > 0:17:02The year after the S51 went down, Momsen submitted plans to the Navy's
0:17:02 > 0:17:08bureau of construction for a device that could rescue trapped submariners.
0:17:08 > 0:17:13Over a year later, he discovered that they hadn't even been opened.
0:17:13 > 0:17:19He conceived of the notion of the bell, the rescue chamber and
0:17:19 > 0:17:22they just ignored him.
0:17:22 > 0:17:27It's always difficult to try and prove a point or make your way when
0:17:27 > 0:17:32you're going against the stream or when you're going against the brass
0:17:32 > 0:17:39and, of course, back in those days the Navy was more or less run by what they called surface admirals.
0:17:39 > 0:17:45They had all served on surface vessels and they weren't sympathetic with the submarine service,
0:17:45 > 0:17:52they saw it as a bunch of mavericks and my grandfather was the biggest maverick of all.
0:17:52 > 0:18:00Momsen lobbied the bureau to take his ideas on board, but again and again he was turned down.
0:18:00 > 0:18:06Then in 1927, another sub, the S4, was lost with all hands.
0:18:08 > 0:18:15Determined not to be thwarted by Navy bureaucracy a second time, Momsen began developing rescue ideas
0:18:15 > 0:18:18without the knowledge of his commanding officers.
0:18:18 > 0:18:2215 years before Cousteau invented the aqualung, Momsen set to work on
0:18:22 > 0:18:26something small-scale that he could design and test himself.
0:18:26 > 0:18:34A remarkable breathing device that gave submariners a chance of reaching the surface from 100m down.
0:18:34 > 0:18:41He had a plan for the Momsen lung and they gathered together pieces of
0:18:41 > 0:18:50hose and metal and inner tubes and put together the Momsen lung and then he tested it in a swimming pool
0:18:50 > 0:18:56and risked his own life, so it was his own money, his own life, his own time.
0:18:56 > 0:18:58'The lung resembles and works in rough principle like a gas mask.
0:18:58 > 0:19:03'Air exhaled into the device passes through soda lime which
0:19:03 > 0:19:06'removes the waste carbon dioxide and replaces it with fresh oxygen.
0:19:06 > 0:19:09'When each student has mastered the use of the lung,
0:19:09 > 0:19:12'he is then ready for the first attempt at underwater breathing.
0:19:12 > 0:19:16'The preliminary ascent is made from a very shallow level.'
0:19:19 > 0:19:21Crikey, it looks like a hot-water bottle.
0:19:21 > 0:19:24Doesn't it? It does. It does.
0:19:24 > 0:19:26OK, how does it work?
0:19:26 > 0:19:31- I met a man who actually was saved with this from the Tang.- This one?
0:19:31 > 0:19:34- Yeah, out in the Formosa Straits. - Oh, I'd better be careful with this.
0:19:34 > 0:19:38He ascended from a submarine with this.
0:19:38 > 0:19:40And this is what goes in your mouth.
0:19:40 > 0:19:42Right, that looks like a modern-day...
0:19:42 > 0:19:44- Right.- ..regulator mouthpiece.
0:19:44 > 0:19:45Hold that up.
0:19:52 > 0:19:55'Charging their lungs with oxygen, the men pass up through the escape hatch
0:19:55 > 0:19:58'one at a time, holding securely to the
0:19:58 > 0:20:03'marker line and taking particular care to pause at the designated intervals for decompression.'
0:20:03 > 0:20:09The Momsen lung was the first truly successful underwater breathing device for a submariner.
0:20:09 > 0:20:13Filled with pure oxygen that recycled during breathing, it didn't allow you to stay
0:20:13 > 0:20:18under water for long, but it could save the life of a stranded sailor.
0:20:18 > 0:20:24'This man has safely reached the surface from a depth of 100 feet.'
0:20:27 > 0:20:34Wow. You've got the same pressure as on me, the water pushing on here, so equal pressure.
0:20:34 > 0:20:38- Right.- Fantastic. It just seems incredibly simple.
0:20:38 > 0:20:43- Yeah, it does.- I mean there's no diving gear, no diving suit.- No.
0:20:43 > 0:20:47Get that escape-hatch pressure equalised.
0:20:47 > 0:20:52- Mmm.- Open it, put this in, goggles on, make a run for it.- Right.
0:20:52 > 0:20:53Wow.
0:20:53 > 0:20:56'At the submarine base in Pearl Harbor...'
0:20:56 > 0:21:01This time the top brass couldn't ignore Momsen and, begrudgingly, they came round to his idea.
0:21:01 > 0:21:07'Under the supervision of Admiral Momsen, inventor of the famous Momsen lung, the future submariners
0:21:07 > 0:21:12- 'are ready for the 100-foot tower which holds...'- The Navy adopted the Momsen lung, as it became known.
0:21:12 > 0:21:16Thousands were ordered to equip every sub in the fleet.
0:21:18 > 0:21:24Floyd Matthews worked with Momsen, training submariners to use the lung.
0:21:24 > 0:21:27He's now 103.
0:21:27 > 0:21:33That's 100 feet, you know, we had three different positions -
0:21:33 > 0:21:38the bottom - that's 100 feet, one at 18 feet, one at 50.
0:21:38 > 0:21:42You see, we gradually worked them up to 100 feet.
0:21:42 > 0:21:45- You could do 100 foot, no problem? - Oh, yeah.
0:21:45 > 0:21:49I could jump overboard and go along the bottom.
0:21:51 > 0:21:54Yeah.
0:21:54 > 0:21:58You exhale and you just keep on going down but you've got
0:21:58 > 0:22:01to have something to breathe when you get there, though.
0:22:02 > 0:22:04You're empty.
0:22:04 > 0:22:05Yeah.
0:22:05 > 0:22:08So what are your memories of Momsen?
0:22:08 > 0:22:10He was an innovator, you know.
0:22:10 > 0:22:14The man was just nothing less than a genius
0:22:14 > 0:22:17and he could do anything, just about, yes.
0:22:22 > 0:22:26The Squalus was equipped with Momsen lungs for all its crew.
0:22:30 > 0:22:36The men had been trained how to use them, but Captain Naquin was deeply concerned.
0:22:36 > 0:22:42The Atlantic was freezing cold and the chances of getting all 33 men out were remote.
0:22:48 > 0:22:52We had planned an escape using a Momsen lung.
0:22:52 > 0:22:59We had the grease, we had the lungs, the water was cold, of course,
0:22:59 > 0:23:06and we were going to grease down and the captain had selected Greek Medeiros to be the first man out to
0:23:06 > 0:23:13let the buoy out with the line on it because we had to have a line to keep us from shooting up to the surface.
0:23:13 > 0:23:18We could have gotten...the first group could have gotten out of the boat, no question, but whether he
0:23:18 > 0:23:23could keep going or not, that was questionable.
0:23:23 > 0:23:29Anyhow, we had used up a lot of oxygen and the old man decided that
0:23:29 > 0:23:35it was safer to wait than it was to try and escape, so...he decided to wait.
0:23:40 > 0:23:47But Captain Naquin had no idea that his last location radioed back to base had been garbled.
0:23:47 > 0:23:48They were lost.
0:23:58 > 0:24:03With the Squalus now out of radio contact for several hours, a second submarine from the
0:24:03 > 0:24:07Portsmouth navy yard had been sent to her last reported position...
0:24:09 > 0:24:12..not realising it was looking in the wrong place.
0:24:18 > 0:24:23There was no sign of the Squalus' marker buoy and no trace of any flares.
0:24:25 > 0:24:28The search dragged on and on.
0:24:34 > 0:24:39In the sub below, cold and hunger were taking hold.
0:24:45 > 0:24:50With surface contact long overdue, tinned food was given out to keep up morale.
0:24:57 > 0:25:00Pineapple seemed to be a favourite.
0:25:06 > 0:25:09Man, it was cold.
0:25:09 > 0:25:16Every place that you had condensation in the torpedo room from your breathing...
0:25:16 > 0:25:18a skim of ice.
0:25:21 > 0:25:25But cold and hunger weren't the only dangers.
0:25:25 > 0:25:29With every breath they took, the men were using up vital oxygen,
0:25:29 > 0:25:35and with each passing hour, the chances of survival became ever slimmer.
0:25:38 > 0:25:44Yet four hours after the Squalus went missing, nobody even knew where she was.
0:25:57 > 0:26:01Off the coast of New Hampshire, Squalus' sister ship, the Sculpin,
0:26:01 > 0:26:04was desperately searching for the downed sub.
0:26:04 > 0:26:10Finally at 12.40 on the 23rd May, the lookout spotted Squalus' marker buoy
0:26:10 > 0:26:16and inside was the telephone connected to the submarine.
0:26:18 > 0:26:20NAQUIN: 'This is the USS Squalus, over.'
0:26:22 > 0:26:24This is the USS Squalus.
0:26:24 > 0:26:26Is there anybody up there? Over.
0:26:26 > 0:26:28'USS Sculpin. Are you receiving?
0:26:28 > 0:26:29- 'Over.'- Yes...
0:26:31 > 0:26:34Hello?
0:26:34 > 0:26:37This is the USS Squalus.
0:26:37 > 0:26:42Just as Captain Naquin said a few words, a big swell came up
0:26:42 > 0:26:44and broke the cable.
0:26:44 > 0:26:46Communication was lost with the submarine,
0:26:46 > 0:26:51but the men on the top did know that some of those men were alive.
0:26:51 > 0:26:56They could do nothing to help them and the whole world was watching.
0:26:58 > 0:27:05'May 23rd 1939, the submarine Squalus lies on the ocean bottom off Portsmouth, New Hampshire.
0:27:05 > 0:27:07'59 men are trapped inside...'
0:27:07 > 0:27:13As a fleet assembled above the Squalus, the world knew there were survivors below.
0:27:13 > 0:27:15Papers rushed to print the story.
0:27:15 > 0:27:18The plight of the crew became front-page news.
0:27:20 > 0:27:24The pressure was on to do something for the men,
0:27:24 > 0:27:32but so far no crew had even been rescued from a sunken sub - it was simply too difficult a challenge.
0:27:32 > 0:27:37For wives and families waiting in the town of Portsmouth, it was an agonising time.
0:27:41 > 0:27:48The whole of the town here at Portsmouth was looking at the navy base over there for answers.
0:27:50 > 0:27:55The whole town would have just been waiting and hoping for news.
0:28:12 > 0:28:18In the sub itself, the precious air was becoming fouler by the minute.
0:28:18 > 0:28:21Each time the men breathed out, oxygen was being replaced with
0:28:21 > 0:28:27poisonous carbon dioxide which had to be mopped up with soda lime.
0:28:37 > 0:28:45In desperation, the Navy at last turned to the man they had once ignored...Charles Momsen.
0:28:48 > 0:28:51Still unrelenting in his drive to improve safety,
0:28:51 > 0:28:55he was quietly tucked away in research and development.
0:28:55 > 0:28:59Following his success with the lung, Momsen had dusted off his plans for
0:28:59 > 0:29:03the rescue chamber, which had originally been scorned by the top brass.
0:29:09 > 0:29:15This is a submarine rescue bell based on Momsen's design.
0:29:15 > 0:29:20It's an incredible simple bit of kit, hardly any moving parts at all.
0:29:20 > 0:29:25It was counted on as being something that would rescue 30-plus men.
0:29:25 > 0:29:29And yet it was just completely unproven.
0:29:29 > 0:29:32Just countless gauges and valves in here.
0:29:32 > 0:29:35Some of them are to control buoyancy,
0:29:35 > 0:29:38some are to control winches,
0:29:39 > 0:29:42and I can't believe you'd get two operators in here and up
0:29:42 > 0:29:47to seven rescued men - there's absolutely no room whatsoever.
0:29:50 > 0:29:53The trick to it is sending it down to the bottom
0:29:53 > 0:29:57and accurately locating it over the submarine escape hatch,
0:29:57 > 0:30:01and the key to that is this thing here.
0:30:01 > 0:30:06There's a rubber gasket under there and that provides a perfect seal over the hatch.
0:30:06 > 0:30:09When this reaches the submarine,
0:30:09 > 0:30:13the water is blown out of it and the water pressure itself,
0:30:13 > 0:30:17which at the Squalus' depth was about 120 lbs per square inch,
0:30:17 > 0:30:22pushes this on to the submarine and squeezes it in place.
0:30:22 > 0:30:29It provides a perfect seal, the men can open up the hatch from inside and enter into here.
0:30:30 > 0:30:36The problem, though, is if this isn't sat absolutely level,
0:30:36 > 0:30:43you get an imperfect seal, the whole of the sea can just rush in - complete disaster.
0:30:47 > 0:30:53'Rescue vessels, led by the Falcon, locate the sub and prepare to send down a newly developed rescue bell.'
0:30:53 > 0:30:55It was Momsen's big moment.
0:30:55 > 0:30:59With 33 lives at stake and time running out, the Navy had
0:30:59 > 0:31:03to take a chance with the maverick inventor and his innovative chamber.
0:31:05 > 0:31:10'Never before has a diving bell like that been used for actual rescue.
0:31:10 > 0:31:12'Will it work, and at that depth?
0:31:12 > 0:31:15'Aboard the rescue fleet, they can only hope.'
0:31:15 > 0:31:21For the chamber seal to work, it had to fit precisely over the sub's escape hatch.
0:31:24 > 0:31:30This meant a diver had to go down first to attach a guide cable to the hatch handle.
0:31:33 > 0:31:38The divers who took on this challenge were the astronauts of their day.
0:31:38 > 0:31:42Tough and determined, they risked their lives to push the
0:31:42 > 0:31:47boundaries of human knowledge, with only the most primitive equipment.
0:31:47 > 0:31:51And this is the kind of kit they had to use.
0:31:51 > 0:31:56It's called hard-hat gear and it's very heavy and cumbersome.
0:31:56 > 0:32:00One boot alone, this weighs about ten kilos.
0:32:00 > 0:32:05So some real problems with it. Firstly, you can only dive very, very close to the ship
0:32:05 > 0:32:08because the diver is lowered down from the boat on the surface.
0:32:08 > 0:32:14Secondly, they're pulling a long air hose behind them and that air hose in Momsen's case
0:32:14 > 0:32:19would have been 75 metres long so it would have weighed a ton, making the dive almost impossible.
0:32:21 > 0:32:24But it wasn't just the diving gear that was primitive.
0:32:24 > 0:32:32At the time, we only had a very basic understanding of how our bodies react to being at pressure.
0:32:32 > 0:32:36So Momsen dedicated himself to learning how that happened
0:32:36 > 0:32:42and he developed diving tanks, just like this one used by the Royal Navy here at Gosport.
0:32:52 > 0:32:57What Momsen and his team were beginning to discover was that as a diver descends, water pressure
0:32:57 > 0:33:03squeezes nitrogen from the air being breathed into a diver's bloodstream and body tissues.
0:33:15 > 0:33:19At high pressure, like there are right here,
0:33:20 > 0:33:27at 30 metres, at high pressure, this nitrogen affects our thinking.
0:33:27 > 0:33:30It's a very pleasant feeling, let me tell you,
0:33:30 > 0:33:38but it can lead to problems because it feels like a mildly drunken state
0:33:38 > 0:33:43and it means that, as pleasant as it feels to me, and I've had it,
0:33:43 > 0:33:47and I guess I must be experiencing it right now,
0:33:47 > 0:33:51it means that on a deep work dive, it could lead to fatal mistakes.
0:34:04 > 0:34:0924 hours after the Squalus went down, the first diver was ready
0:34:09 > 0:34:13to be lowered into the freezing waters of the North Atlantic.
0:34:13 > 0:34:19'Deep in the sea there, 33 men are alive, in danger of dying for lack of air.
0:34:19 > 0:34:23'"Get the living out!" is the cry as down goes the diver.'
0:34:25 > 0:34:27The diver was Martin Sibitzky.
0:34:36 > 0:34:40His task was crucial to the rescue - he had to fasten the cable which
0:34:40 > 0:34:44would guide the bell down to the sub's escape hatch.
0:35:01 > 0:35:05With the concentration of carbon dioxide rising with every breath,
0:35:05 > 0:35:09the air in the sub was becoming more poisonous by the minute.
0:35:18 > 0:35:21Sibitzky had to succeed, and quickly.
0:35:21 > 0:35:25On this mission, there was no room for error.
0:36:04 > 0:36:08When Sibitzky got down there and started to work really hard
0:36:08 > 0:36:16dragging that heavy cable around, he was breathing more air, which meant that he got nitrogen narcosis.
0:36:16 > 0:36:21He became physically fatigued and very confused, almost drunk.
0:36:24 > 0:36:30The rescue was on the verge of collapse when, back on deck, Momsen stepped in.
0:36:34 > 0:36:42Momsen knew exactly what Sibitzky was going through, so he talked him through it, step by careful step.
0:36:45 > 0:36:53Momsen helped Sibitzky gather his thoughts and overcome the effects of nitrogen narcosis.
0:36:53 > 0:36:57At last he was able to clip the cable on.
0:37:04 > 0:37:07The first stage of the operation was complete...
0:37:09 > 0:37:12but the hardest part was still to come.
0:37:12 > 0:37:17Now it was time for Momsen's chamber to be put to the test.
0:37:17 > 0:37:20'The crew of the rescue chamber climb in for their risky adventure.
0:37:20 > 0:37:24'The idea is to lower it onto the sunken sub, make it fast to a hatch,
0:37:24 > 0:37:28'open the hatch and bring the survivors up into the rescue chamber.
0:37:28 > 0:37:32'So beneath the surface it sinks, for life saving without precedent.
0:37:32 > 0:37:34'This occurs a little more than 24 hours
0:37:34 > 0:37:39'after the US Submarine Squalus sank while making a practice dive off Portsmouth.'
0:37:41 > 0:37:45Lowered by a support cable, the chamber began its descent.
0:37:48 > 0:37:52Though it had never been tested in a real rescue situation,
0:37:52 > 0:37:55it was the only hope for the men in the Squalus.
0:38:02 > 0:38:05But would it work? Would the seal hold?
0:38:15 > 0:38:20At 12 noon, the chamber landed over the escape hatch.
0:38:41 > 0:38:44The seal held.
0:38:49 > 0:38:50Yeah!
0:38:53 > 0:38:5930 hours after the Squalus first hit the bottom, the unbelievable had happened.
0:38:59 > 0:39:02A rescue mission had reached the submarine.
0:39:06 > 0:39:10Carl Bryson watched the first eight men get into the bell.
0:39:10 > 0:39:15They were the crew members most affected by the cold and poor air.
0:39:20 > 0:39:24It was essential to get the weakest to the surface first.
0:39:24 > 0:39:28No-one knew how long the rescue would last, if the weather would hold
0:39:28 > 0:39:35or indeed if the bell could actually manage the four journeys needed to lift the survivors to safety.
0:39:41 > 0:39:46Under Momsen's orders, the bell was raised carrying the first survivors.
0:39:49 > 0:39:53Valves let in air to the ballast tanks,
0:39:53 > 0:39:57and inch by inch, the chamber rose...
0:39:57 > 0:40:00..guided by the cable to the ship above.
0:40:08 > 0:40:12For now, everything seemed to be working perfectly.
0:40:18 > 0:40:22At last, the bell made it to the surface.
0:40:28 > 0:40:30'There is it bubbling and breaking the water,
0:40:30 > 0:40:34'the dramatic sight, the sudden appearance of the diving bell.
0:40:34 > 0:40:38'All the rescue power of the Navy mobilised and here is the climax,
0:40:38 > 0:40:41'the rescue chamber coming up from its first descent.
0:40:45 > 0:40:47'Hoisted up. What's in it?
0:40:47 > 0:40:50'There are anxious wives and family waiting tensely.
0:40:50 > 0:40:56'Open it up and then out they climb, survivors, the first one.
0:40:56 > 0:41:01'So weak he has to be helped after being entombed for 24 hours at the bottom of the sea.
0:41:01 > 0:41:08'One after the other, seven in all are brought up in this first trip of the rescue chamber.'
0:41:08 > 0:41:10It was a historic moment.
0:41:10 > 0:41:14For the first time ever, men had been rescued from a submarine on the sea floor
0:41:14 > 0:41:20and in that instant, everything Momsen had worked for was validated.
0:41:20 > 0:41:24But it was far from over. There were still 25 men to be brought up.
0:41:24 > 0:41:29The sub was freezing and the air was getting fouler by the minute.
0:41:29 > 0:41:31There was no time to waste.
0:41:33 > 0:41:40The next two dives went without a hitch, with 18 more men being brought up safely to the surface.
0:41:42 > 0:41:49The chamber was sent back down to the Squalus for the final time, a little before 8pm.
0:41:49 > 0:41:55For Carl Bryson and the last few survivors, struggling against rising carbon dioxide
0:41:55 > 0:42:01and the constant threat of chlorine gas, it seemed to be the end of their ordeal.
0:42:01 > 0:42:05So we were all up there and...waiting.
0:42:07 > 0:42:09Seemed like it took hours.
0:42:09 > 0:42:13Man, it was cold and the air was horrible.
0:42:13 > 0:42:15It was getting worse all the time.
0:42:25 > 0:42:28How did it feel getting in that bell?
0:42:28 > 0:42:33Well, it felt good to get in the bell, but when it jammed, it didn't feel so good.
0:42:43 > 0:42:47The bell had only risen about ten metres when it stuck fast.
0:42:50 > 0:42:55The main cable running down from the bell to the sub below had jammed.
0:43:04 > 0:43:10Diver Walter Squire was sent down into the water to free the stuck cable.
0:43:10 > 0:43:12He made his way down tentatively.
0:43:24 > 0:43:27Squire fumbled around for the cable a few metres below the bell,
0:43:27 > 0:43:30he tried to free it but it wouldn't budge.
0:43:30 > 0:43:34So on Momsen's orders, he cut it.
0:43:38 > 0:43:41Now the full weight of the nine-and-a-half-tonne chamber was
0:43:41 > 0:43:47hanging from a single support cable running to the ship above.
0:43:51 > 0:43:53Just when it seemed the worst was over,
0:43:53 > 0:43:57the diver returning to the surface noticed something disastrous.
0:43:57 > 0:44:02The cable left holding the chamber had begun to unravel and snap
0:44:02 > 0:44:07and the bell was now dangling from a last single strand.
0:44:07 > 0:44:12The men's lives were literally hanging by a thread.
0:44:12 > 0:44:17Afraid that this last strand would break, Momsen had to order the chamber gently lowered back down to
0:44:17 > 0:44:23the sea bed, so just moments from triumph, the rescue had stalled.
0:44:37 > 0:44:42Momsen had them drop us back down in the mud, we were up to 150 foot level then.
0:44:50 > 0:44:55They dropped us back down because if that cable had parted
0:44:55 > 0:45:01and the exhaust cable and the air cable, then we would be lost.
0:45:05 > 0:45:11With the last of the survivors trapped inside the bell, Momsen came up with an all-or-nothing plan.
0:45:11 > 0:45:14It was highly risky, but it was their only hope.
0:45:16 > 0:45:20He reckoned if the operators inside the bell could carefully open the
0:45:20 > 0:45:25valves and blow more compressed air in, they could control its buoyancy,
0:45:25 > 0:45:30and his gamble was that they could make it weightless - neither rising nor sinking.
0:45:30 > 0:45:37If it worked, it would be light enough that it could be carefully hauled up, hand over hand.
0:45:37 > 0:45:42If it didn't, the cable would break and the men would be lost.
0:45:50 > 0:45:56He told McDonald to blow for ten seconds, you know.
0:45:56 > 0:45:59So McDonald blow the lower compartment.
0:46:06 > 0:46:08Then blow 20 seconds...
0:46:11 > 0:46:14Then he blow 10 seconds.
0:46:24 > 0:46:28Finally, they pulled us clear of the mud
0:46:28 > 0:46:39and they had all these people up on the deck, pulling this thing by hand and we got up to about 150 feet and
0:46:39 > 0:46:41we went right to the surface like that.
0:46:41 > 0:46:45'One of the greatest rescues in the annals of the sea, men saved
0:46:45 > 0:46:49'from the sunken submarine Squalus off Portsmouth, New Hampshire.
0:46:49 > 0:46:51'Every one of the living brought out alive.
0:46:51 > 0:46:56'In the history of the sea, a sunken submarine represents the depth of terror and horror.
0:46:56 > 0:46:59'This rescue represents a height of glory.'
0:47:01 > 0:47:03We got to the surface...
0:47:05 > 0:47:09and I was frozen, man, oh, man.
0:47:12 > 0:47:14I tell you, we were lucky, really lucky.
0:47:17 > 0:47:22And we had the right people in the right place at the right time.
0:47:26 > 0:47:27That makes the difference.
0:47:34 > 0:47:39Momsen had done it, he'd saved the lives of 33 men.
0:47:39 > 0:47:43The rescue of the crew from the Squalus showed for the first time
0:47:43 > 0:47:48that something really could be done for men trapped on the ocean floor.
0:47:49 > 0:47:54It was a pivotal moment in the history of undersea exploration.
0:47:54 > 0:48:00The Squalus rescue, carried out under the glare of the world's press, had put submarine
0:48:00 > 0:48:07safety firmly on the agenda, and within six months of the Squalus sinking, the US Navy
0:48:07 > 0:48:15had offered the diving bell plans to 13 other countries in a bid to make submarines safer round the world.
0:48:19 > 0:48:22As a proven success, it was adopted by other navies.
0:48:27 > 0:48:32And even today, a version of the rescue chamber is still in use.
0:48:35 > 0:48:37It's called the McCann chamber.
0:48:37 > 0:48:40Named after Momsen's successor in the development programme.
0:48:48 > 0:48:51Thanks, mate. I'm here, courtesy of the Italian Navy,
0:48:51 > 0:48:56to take part in a submarine rescue training exercise and I'm going to go down here in a McCann bell, which
0:48:56 > 0:49:00is essentially the same piece of kit that was used in the Squalus rescue,
0:49:00 > 0:49:02to go down to a submarine at 40 metres,
0:49:02 > 0:49:07to see what it was really like for those rescuers and for those men from the Squalus.
0:49:07 > 0:49:09Thanks very much.
0:49:09 > 0:49:11Thank you.
0:49:19 > 0:49:22INDISTINCT SPEECH
0:49:27 > 0:49:29Very good.
0:49:38 > 0:49:42HE SPEAKS ITALIAN
0:49:42 > 0:49:44I can feel the pressure
0:49:44 > 0:49:46increasing now.
0:49:46 > 0:49:49That's because the water is coming in the lower part of the bell
0:49:49 > 0:49:53and squeezing all the air into this part of the chamber.
0:49:53 > 0:49:55Yeah.
0:49:58 > 0:50:01The bell is noisy, it looks primitive,
0:50:01 > 0:50:05the air pressure varies wildly as you go up and down, but it works.
0:50:05 > 0:50:08The Italians see it almost as an elevator that can run
0:50:08 > 0:50:11back and forth from the surface to the sea bed.
0:50:18 > 0:50:20We've just landed on a submarine!
0:50:27 > 0:50:35It's fantastic to think that a design which is essentially from the '30s is still used today.
0:50:35 > 0:50:37And it's not just the Italians.
0:50:37 > 0:50:42The Turks, Indians and the US still use essentially the same design
0:50:42 > 0:50:48as Momsen's original bell that triumphed in the Squalus rescue.
0:50:48 > 0:50:51It's really surreal, actually, because there's the submarine,
0:50:51 > 0:50:54that's the top of the submarine,
0:50:54 > 0:50:56we're 40 metres in the bottom of the sea.
0:51:07 > 0:51:11It's just amazing... going down to a submarine
0:51:11 > 0:51:12whilst on the bottom of the sea.
0:51:18 > 0:51:22Oh, wow.
0:51:22 > 0:51:24Hey, thanks for this, guys.
0:51:24 > 0:51:26Thanks very much.
0:51:28 > 0:51:33Good Italian espresso served at 40 metres on the bottom of the Med.
0:51:33 > 0:51:38I'm going to remember this next time I'm scuba diving at 40 metres and freezing.
0:51:38 > 0:51:42Dry, good coffee, good company...
0:51:42 > 0:51:44Here we go.
0:51:49 > 0:51:54The Squalus rescue was a turning point in the development of underwater technology.
0:51:56 > 0:52:03New devices were pioneered that led to some remarkable equipment like this one-atmosphere diving suit.
0:52:06 > 0:52:11In one of these, a diver can work hundreds of metres down on the ocean floor, allowing the construction
0:52:11 > 0:52:16and maintenance of many of today's most ambitious engineering projects,
0:52:16 > 0:52:21like North Sea oil platforms and the undersea pipelines leading from them
0:52:21 > 0:52:24which run hundreds of miles along the ocean floor.
0:52:24 > 0:52:29These developments would have seemed impossible before Momsen's triumph.
0:52:31 > 0:52:37After the Squalus rescue, Momsen was promoted to Commander and his prestige in the Navy just rocketed.
0:52:37 > 0:52:40He used his influence to launch a whole new era
0:52:40 > 0:52:44of underwater technology and he became the father of modern diving.
0:52:44 > 0:52:51One of his most significant contributions was the development of new mixed gasses for deep diving.
0:52:51 > 0:52:58By replacing the nitrogen in the air with helium, he completely eliminated nitrogen narcosis.
0:52:58 > 0:53:02That meant that professional divers like myself can dive deeper, we can
0:53:02 > 0:53:07have shorter decompression times and underwater work is just safer.
0:53:09 > 0:53:15In the '60s, Momsen's son, also called Charles, was a real chip off the old block.
0:53:15 > 0:53:19He carried on the family tradition by developing the mini-sub Alvin,
0:53:19 > 0:53:26seen here looking for a hydrogen bomb lost at sea after a mid-air collision involving a B52 bomber.
0:53:30 > 0:53:34Since Alvin was first designed, mini-subs have become lighter
0:53:34 > 0:53:39and more manoeuvrable, with ever more specialised functions.
0:53:39 > 0:53:45Nowadays they're used all over the world, both by navies and civilian contractors.
0:53:49 > 0:53:55As well as submarine rescue and training, they're used for things like investigating wrecks, searching
0:53:55 > 0:54:02for lost aircraft, inspecting marine structures and even filming the secret habits of deep-sea creatures.
0:54:05 > 0:54:12And one man's vision of what was possible beneath the sea helped pave the way for technology like this.
0:54:14 > 0:54:17Momsen was a true pioneer.
0:54:17 > 0:54:24He revealed to the world that hugely complex diving operations can take place deep below the surface.
0:54:24 > 0:54:31The rescue of the Squalus gave people confidence as they dived ever deeper into this alien world.
0:54:34 > 0:54:36Momsen gave hope.
0:54:36 > 0:54:42So should things go wrong down here in the abyss, we know that help can be on its way.
0:54:46 > 0:54:53After a lifetime dedicated to the safety of men at sea, Momsen died in 1967.
0:54:54 > 0:55:00In 2004, the Navy paid him its highest honour and named a destroyer after him.
0:55:05 > 0:55:10As for the Squalus itself, it was salvaged from the deep in the months after it sank.
0:55:14 > 0:55:19Recommissioned as the Sailfish, it fought through the Second World War.
0:55:23 > 0:55:27Her conning tower is still preserved at Portsmouth Navy Yard
0:55:27 > 0:55:30as a lasting tribute to the men who served on her.
0:55:34 > 0:55:37How does it feel to be on here now, Carl?
0:55:37 > 0:55:40Well, brings back a lot of memories.
0:55:40 > 0:55:44I lost some very close friends on this boat.
0:55:53 > 0:55:54It...
0:55:56 > 0:56:00It was a sad thing, it was a heavy price to pay.
0:56:02 > 0:56:06Do you think it gave you a unique perspective on life itself?
0:56:06 > 0:56:09Oh, yes, oh, yes. Well...
0:56:09 > 0:56:11let's say I was always lucky.
0:56:11 > 0:56:13I was lucky since then.
0:56:13 > 0:56:17I was very lucky, I married a wonderful woman and I got
0:56:17 > 0:56:22three wonderful children and six wonderful grandchildren.
0:56:22 > 0:56:25Can't get much luckier than that!
0:56:25 > 0:56:28If Swede Momsen was here today, what would you say to him?
0:56:28 > 0:56:30Thank you, Swede.
0:56:31 > 0:56:33You betcha.
0:56:34 > 0:56:40I...I couldn't emphasise my gratitude enough, believe me.
0:56:40 > 0:56:45I have a medication that I take in my room
0:56:45 > 0:56:50and I have a picture of Swede about so big up on my bookcase
0:56:50 > 0:56:55and when I take the medication I always say, "Thank you, God,"
0:56:55 > 0:56:58and "Thank you, Swede."