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00:01In May 1939, the crew of the submarine USS Squalus was struck by disaster deep below the surface of the
00:09Atlantic Ocean.
00:17They were trapped on the ocean floor with their air running out and no means of escape.
00:24The latest victims of what the US Navy dubbed the Coffin Service.
00:42Their fate depended on one man, naval inventor Charles Swede Momsen.
00:52Momsen's attempt to rescue the men of the Squalus would become one of the most celebrated rescue missions in maritime
00:58history.
01:01It kick-started a whole new era of underwater technology and revolutionised our understanding of what can be achieved in
01:08the dangerous and alien world deep beneath the waves.
01:28On May the 23rd 1939, a prototype American submarine was preparing for a routine dive.
01:38The exercise was taking place 25 kilometres off New Hampshire on the east coast of America.
01:51This was the USS Squalus's 19th test dive, a timed crash dive for use in emergencies.
02:03First officer, prepare to dive the boat!
02:08Under the command of Lieutenant Oliver Naquin, the Squalus had to dive to periscope depth 15 metres in 60 seconds.
02:21A series of levers closed the valves that fed air to the diesel engines.
02:28Green signalled that the sub was watertight.
02:34At 7.40am, the dive began.
02:48Mark.
02:5062 seconds.
02:52Well done, gentlemen.
02:56It seemed a textbook dive, but within seconds it went disastrously wrong.
03:21Unbelievably, water was pouring through the main induction valves in the rear of the sub.
03:262.
03:272.
03:292.
03:334.
03:34Hedgn.
03:344.
03:355.
03:365.
03:384.
03:396.
03:396.
03:396.
03:405.
03:416.
03:415.
03:424.
03:424.
03:476.
03:55somehow despite the all clear on the control panel a valve was open and hundreds of tons
04:01of water were pouring in the sub they lost control of her she went down to the bottom
04:07now i'm a professional diver and i know what it's like when things go wrong
04:11but i've benefited from immediate backup these men were on their own what's going to happen to
04:18them bearing in mind that in the previous 20 years worldwide 22 subs have been lost along with the
04:26lives of over a thousand men i didn't call it the coffin service for nothing
04:35in the 1930s submariners like the crew of the squalas were taking their lives in their hands
04:42underwater technology was in its infancy and in the history of submarines no crew had ever been
04:49rescued from the ocean depths the disaster of the squalas will become a pivotal event that would
04:56change underwater safety forever even today flooding is a danger that terrifies every submariner and
05:05recruits are trained how to react to any breach of their boat in this simulator the sheer force of
05:13a wall of water pouring through at 14 pounds per square inch pressure is a terrifying experience
05:27this is really hard work but because i knew it was going to happen those men on the squalas it
05:33would
05:33have just been a sudden tremendous shock freezing cold water and the high pressure you see we're here at
05:40the surface even a periscope deck it's twice what the pressure will need to the surface the water would
05:47have just come pouring in after ever increasing pressure it wasn't long despite their best efforts
05:53before the men in the rear of the sub were completely overwhelmed
06:00within a few minutes water was flooding from the rear to the front of the sub
06:07as men struggled desperately forwards the crew who'd already made it into the control room faced an
06:13agonizing decision either wait for their crew mates to come through and risk the whole sub flooding
06:21or shut the watertight bulkhead doors and condemn them to certain death
06:30they were ordered to seal the control room
06:34so
06:58so
06:5826 men died in those first few minutes
07:0233 survivors were entombed in what was now a watery coffin stranded on the bottom of the ocean
07:2339 year old carl bryson is the last living survivor from the squalas
07:30carl joined the navy as a teenager in 1936
07:34by the summer of 1939 he was a 22 year old machinist mate serving aboard his second sub
07:43he was in the forward battery when the squalas went down
07:52i never really thought about dying there that would never cross my mind when the water first started to
07:59come in uh i didn't have time to think about anything except how to shut the water off everybody said
08:05well what did you think and all that i didn't think anything except how can we stop the water from
08:11coming in this is the main induction valve all the water would have come in here massive volumes of
08:18water pouring in these tremendous volume and it went into both engine roads
08:28the crew in the forward section of the squalas had survived the initial flooding
08:33but now they were trapped with only enough air to survive for 48 hours
08:39and a new danger was already upon them
08:44water was seeping into the forward battery compartment threatening to short circuit the huge
08:49batteries that powered the sub's electric motors this is a ford battery of course this is a battery hatch
08:57luke opened the hatch and the bitumastic was bubbling and the caps on the batteries were coming
09:05out and so the battery was overheating we were pulling several thousand amps
09:14as the batteries heated to a critical level the chief electrician shut off her power
09:27another 30 seconds probably and we would have had a battery explosion
09:40nobody in the battery compartment would have stayed alive the people in the control room would have been lost
09:48somebody may just possibly have made it out of the ford torpedo room i doubt it
09:57with no power there was no heating no light and no hope of raising the sub
10:04the captain naquin it was time to make a harrowing assessment
10:12take a roll call yes sir bryson hi sir but please hi sir ask you jones hi sir
10:24F torpedo do you copy F torpedo do you copy F torpedo do you copy
10:38forward battery do you copy
10:44forward torpedo do you copy
10:53do you copy
10:53with almost half her crew dead a dwindling air supply no power
10:58and no way of reaching the surface this was a submariner's worst nightmare
11:11ever since the sinking of the lusitania in world war one by a german u-boat
11:15naval commanders knew they needed submarines
11:21but the early models produced on both sides of the atlantic some of which were even powered by
11:26steam were often a greater danger to their own crews than enemy shipping they were steel death traps
11:36submarine design had moved on by the 30s but despite the image portrayed in recruitment films
11:43service underwater was still cramped noisy and highly dangerous
11:48the men who served in them had a reputation as mavericks kind of naval pirates
11:54it's said the admirals of the day saw these crews as expendable
12:00but despite the dangers there was pressing reasons why young americans of the 1930s signed up for the coffin service
12:09millions of americans men women and children wait in the cold on bread lines in soup kitchens
12:16the great depression of 1929 threw america into turmoil by 1932 the economy had virtually collapsed
12:25private construction virtually ceases mills and factories shut down railroads come to a virtual standstill
12:33there were 15 million unemployed and the wealth of the average american had dropped to the level of 25
12:39years earlier the ranks of the unemployed but the submarine service provided an escape from the hunger
12:45and uncertainty of the times depositors now in greatest need
12:51while the rest of the u.s was gripped by poverty and unemployment young sailors were guaranteed roofs over
12:57their heads three square meals a day and a weekly pay packet here's one place where mess call means
13:04all hands on deck to store cargo and there's plenty of room in the hold for seconds after this man
13:11stows
13:11his gear in his new locker he hangs up a picture of his old school teacher and makes himself at
13:17home in
13:18the comfortable barrack accommodations submariners also got an added bonus an extra 25 or 30 dollars a
13:25month in their pay it's called submarine pay but this extra cash was actually danger money the submarine
13:32service was still the riskiest branch of the navy
13:43for the crew of the stricken squalers trapped on the ocean floor things were going from bad to worse
13:49shut it down chlorine gas get out of here in the forward battery of the sub seawater was reacting
13:55with acid to produce poisonous chlorine gas which was beginning to spread we weren't to the point of gasping
14:07or anything like that but uh we smelled chlorine gas and that certainly is an indicator we wanted out
14:19but there was no way out the stricken sub was on the ocean floor at a depth of 74 meters
14:28radio communication
14:30was impossible that far down and the last message to base had been garbled the sub was actually eight
14:37kilometers from where base understood her to be well and truly lost
14:45the crew released a marker boy and some rocket fleers but the chances of rescue were remote
14:52trapped in america's newest submarine all the men could do was pray
15:01in the 30s and 40s subs built here at portsmouth naval yard were at the forefront of submarine design
15:09and 20 000 men built virtually half of america's submarine fleet for world war ii squalus was at the
15:18cutting edge of these developments and yet still the sea took her now the race was on to find her
15:25but even if she was found the big question remained could those men be saved
15:32the answer to that lay with one man lieutenant charles monson nicknamed swede monson
15:42in 1925 14 years before the squalus disaster monson was a sub commander and was badly shaken by the
15:49tragic sinking of his vessel's sister submarine
15:55of monson in 1925 14 years before the army of monson
15:55stranded on the bottom of the ocean several of monson's friends lost their lives while the navy
16:01stood by helplessly
16:05monson was determined things had to change submarines had to become safer
16:16helen hart monson is charles monson's granddaughter swede monson is her hero and she knows his story
16:24inside out he had lost friends people he went to the naval academy with had been lost in submarine
16:33disasters people that he actually knew um one of the men when they opened the submarine after they
16:40salvaged it his fingers were all torn to stubs because he had tried to open the hatch which would
16:48have been impossible um even without the water on top of it and i guess people just do terrible things
16:55in their final hours and and he was just overwhelmed because at first he thought well it would it wouldn't
17:02be so bad they probably just went to sleep they probably just died a simple death
17:08but then when they opened the hatch and he realized the agony they had gone through
17:13he said it can't be this way it just can't be this way the year after the s51 went down
17:19monson submitted plans to the navy's bureau of construction for a device that could rescue trap
17:25submariners over a year later he discovered that they hadn't even been opened
17:31he conceived of the notion of the the bell the rescue chamber and uh they just ignored him
17:41it's always difficult to try and and prove a point or or make your way when you're going against
17:48the stream or when you're going against the brass and of course back in those days the the navy was
17:55more or less run by what they called surface admirals they had all served on surface vessels
18:01and they weren't really sympathetic with the submarine service they saw it as a a bunch of
18:07mavericks and here my grandfather was the biggest maverick of all monson lobbied the bureau to take his
18:14ideas on board but again and again he was turned down then in 1927 another sub the s4 was lost
18:24with all hands
18:28she said in her body was a man that it was not the fame of the word historically
18:28determined not to be thwarted by navy bureaucracy a second time monson began developing rescue ideas
18:34without the knowledge of his commanding officers 15 years before custeau invented the aqualung monson
18:41set to work on something small scale that he could design and test himself a remarkable breathing
18:47device that gave submariners a chance of reaching the surface from 100 meters down he
18:53had a plan for the mumps and lung and they gathered together pieces of hose and metal and
19:03inner tubes and put together the mumps and lung and he tested it in a swimming pool and risked
19:11his own life. So it was his own money, his own life, his own time. The lung resembles and works
19:17in rough principle like a gas mask. Air exhaled into the device passes through solar line which
19:22removes the waste carbon dioxide and replaces it with fresh oxygen. When each student has mastered
19:27the use of the lung he is then ready for the first attempt at underwater breathing. The preliminary
19:32ascent is made from a very shallow level. Crikey, it looks like a hot water bottle. Doesn't it? It does.
19:42It does. Okay, how does it work? I met a man who actually was saved with this from the Tang.
19:49This
19:50one? Yeah, out in the Formosa Straits. Oh wow, I better be careful with this. He ascended from
19:55the submarine with this and this is what goes on in your mouth. Right, so I recognise that. That
20:00looks like a modern day regulator mouthpiece. I'm holding that up.
20:11Charging their lungs with oxygen, the men pass up through the escape hatch one at a time,
20:16holding securely to the marker line and taking particular care to pause at the designated
20:20intervals for decompression. The Momsen lung was the first truly successful underwater breathing
20:26device for a submariner. Filled with pure oxygen that recycle during breathing, it didn't allow
20:32you to stay underwater for long, but it could save the life of a stranded sailor.
20:38This man has safely reached the surface from a depth of 100 feet.
20:46Wow, you've got the same water, the same pressure as is on me. The water is pushing on here so
20:51equal pressure. Right. Fantastic. I mean, it just seems incredibly simple. Yeah, it does. I mean,
20:58there's no, no diving gear, no diving suit. No. Oh, get that escape hatch, pressure equalised.
21:06Mm-hm. Open it, put this in, goggles on, make a run for it. Right. Wow.
21:13At the submarine base in Pearl Harbor... This time, the top brass couldn't ignore Momsen and begrudgingly,
21:19they came round to his idea. Under the supervision of Admiral Momsen, inventor of the famous Momsen
21:24lung, the future submariners are ready for the 100-foot tower, which holds... The Navy adopted the
21:29Momsen lung as it became known. Thousands were ordered to equip every sub in the fleet.
21:34To bring up a picture record... Floyd Matthews worked with Momsen, training submariners to use
21:41the lung. He's now 103. That's 100 feet, you know. We have three different positions. Of course, the bottom,
21:53that's 103. The one at 18 feet and the one at 50. You see, we gradually worked them up to
22:00100 feet.
22:01You could do 100 foot, no problem? Oh, yeah. Yeah, I could jump over and go right on the bottom.
22:09Great. Yeah. You exhale and you just keep on going down. Or you run out, you better go down,
22:17have something to breathe when you get there, though. You're empty. Yeah.
22:25So, what's your memories of Momsen? He was an innovator, you know. The man was just,
22:30uh, nothing less than a genius. And, uh, he could do anything, just about, yeah.
22:42The Squalus was equipped with Momsen lungs for all its crew.
22:49The men had been trained how to use them, but Captain Naquin was deeply concerned. The Atlantic
22:56was freezing cold, and the chances of getting all 33 men out were remote.
23:07We had planned an escape, using a Momsen lung. We had to grease, we had the lungs, and the water
23:16was
23:16cold, of course. And we were going to grease down, and the captain had selected Greek Madeiros to be the
23:23first man out to let the buoy up with a line on it, because we had to have a line
23:28to go up to keep us from
23:29shooting up the surface. We could have gotten—the first group could have gotten out of the boat,
23:36no question, but whether you could keep going or not, that was questionable. Anyhow,
23:43we had used up a lot of oxygen, and the old man decided that
23:48it was safer to wait than it was to try and escape, so he decided to wait.
23:59But Captain Naquin had no idea that his last location, radio back to base, had been garbled.
24:06They were lost.
24:17With the Squalus now out of radio contact for several hours, a second submarine from the Portsmouth Navy Yard
24:24had been sent to a last reported position, not realising it was looking in the wrong place.
24:37There was no sign of the Squalus' marker boy, and no trace of any flares.
24:44The search dragged on and on.
24:54In the sub below, cold and hunger were taking hold.
25:04With surface contact long overdue, tinned food was given out to keep up morale.
25:17Pineapples seemed to be a favourite.
25:25It was cold.
25:26Man, it was cold.
25:29Every place that you had condensation in a torpedo room,
25:33from your breathing, a skim of ice.
25:41But cold and hunger weren't the only dangers.
25:44With every breath they took, the men were using up vital oxygen.
25:48And with each passing hour, the chances of survival became ever slimmer.
25:58Yet, four hours after the Squalus went missing, nobody even knew where she was.
26:16Off the coast of New Hampshire, Squalus' sister ship, the Sculpin, was desperately searching for the downed sub.
26:24Finally, at 12.40 on the 23rd of May, the lookout spotted Squalus' marker boy.
26:29And inside, was the telephone connected to the submarine.
26:37This is the USS Squalus. Over.
26:42This is the USS Squalus. Is there anybody up there? Over.
26:45This is the USS Dolphin. Are you receiving? Over.
26:48Yes.
26:48They're up now.
26:51Hello?
26:53This is the USS Squalus.
26:56Just as Captain Naquin said a few words, a big swell came up and broke the cable.
27:03Communication was lost with the submarine.
27:05But the men on the top did know that some of those men were alive.
27:10They could do nothing to help them.
27:12And the whole world was watching.
27:18May 23rd, 1939. The submarine Squalus lies on the ocean bottom of Portsmouth, New Hampshire.
27:2459 men are trapped inside.
27:26As a fleet assembled above the Squalus, the world knew there were survivors below.
27:32Papers rushed to print the story. The plight of the crew became front page news.
27:39The pressure was on to do something for the men.
27:43But so far, no crew had ever been rescued from a sunken sub.
27:47It was simply too difficult a challenge.
27:51For wives and families waiting in the town of Portsmouth, it was an agonising time.
28:01The whole of the town here at Portsmouth were looking at the navy base over there for answers.
28:10The whole town would have just been waiting and hoping for news.
28:32In the sub itself, the precious air was becoming fouler by the minute.
28:37Each time the men breathed out, oxygen was being replaced with poisonous carbon dioxide,
28:43which had to be mopped up with soda lime.
28:56In desperation, the navy at last turned to the man they had once ignored.
29:02Charles Mommsen.
29:07Still unrelenting in his drive to improve safety, he was quietly tucked away in research and development.
29:15Following his success with the lung, Mommsen had dusted off his plans for the rescue chamber,
29:19which had originally been scorned by the top brass.
29:29This is a submarine rescue bell based on Mommsen's design.
29:34This incredible simple bit of kit is hardly any moving parts at all.
29:39It was counted on as being something that would rescue 30 plus men.
29:44And yet it was just completely unproven.
29:47I'm looking in here, just countless gauges and valves in here.
29:51Some of them are to control buoyancy.
29:55Some are to control winches.
29:58And I can't think, you get two operators in here and up to seven rescued men.
30:03There's absolutely no room whatsoever.
30:09The trick to it is sending it down to the bottom and accurately locating it over the submarine escape hatch.
30:16And the key to that is this thing here.
30:20There's a rubber gasket under there and that provides a perfect seal over the hatch.
30:25When this reaches the submarine, the water's blown out of it.
30:30And the water pressure itself, which at the squalor's depth is about 120 pounds per square inch,
30:36pushes this on to the submarine and squeezes it in place.
30:41Provides a perfect seal.
30:44The men can open up the hatch from inside and enter into here.
30:49The problem though, is if this isn't sat absolutely level, you get an imperfect seal.
30:57The whole of the sea can just rush in.
31:01Complete disaster.
31:06Rescue vessels led by the Falcon, locate the sub and prepare to send down a newly developed rescue bell.
31:12It was Momsom's big moment.
31:15With 33 lives at stake and time running out,
31:18the Navy had to take a chance with the maverick inventor and his innovative chamber.
31:24Never before has a diving bell like that been used for actual rescue.
31:28Will it work? And at that depth, aboard the rescue fleet, they can only hope.
31:34For the chamber seal to work, it had to fit precisely over the sub's escape hatch.
31:44This meant a diver had to go down first to attach a guide cable to the hatch handle.
31:52The divers who took on this challenge were the astronauts of their day.
31:57Tough and determined, they risked their lives to push the boundaries of human knowledge
32:03with only the most primitive equipment.
32:08And this is the kind of kit they had to use.
32:10It's called hard hat gear and it's very heavy and cumbersome.
32:15I mean, one boot alone, this weighs about 10 kilos.
32:19So there's some real problems with it.
32:21Firstly, you can only dive very, very close to the ship
32:24because the diver is lowered down from the boat on the surface.
32:27And secondly, they're pulling a long air hose behind them.
32:31And that air hose, in Momsom's case, would have been 75 metres long.
32:35So it would have weighed a tonne, making the dive almost impossible.
32:40But it wasn't just the diving gear that was primitive.
32:43At the time, we only had a very basic understanding
32:47of how our bodies react to being at pressure.
32:51So Momsom dedicated himself to learning how that happened.
32:55And he developed diving tanks, just like this one,
32:59used by the Royal Navy here at Gosport.
33:11What Momsom and his team were beginning to discover
33:13was that as a diver descends, water pressure squeezes nitrogen
33:18from the air being breathed into a diver's bloodstream and body tissues.
33:34Well, at high pressures, like there are right here,
33:39at 30 metres, at high pressure, this nitrogen affects our thinking.
33:46It's a very pleasant feeling, let me tell you.
33:49But it can lead to problems, because it feels like a mildly drunken state.
33:57And it means that as pleasant as it feels to me, and I've had it,
34:02and I guess I must be experiencing it right now.
34:06It means that on a deep work dive, it could lead to fatal mistakes.
34:11It means that the squalors went down to the sea of the sea of the sea of the sea of
34:30the sea of the sea of the sea of the sea.
34:41I'm the one who's a diver.
34:44The diver was Martin Sobitski.
34:55His task was crucial to the rescue.
34:58He had to fasten the cable, which would guide the bell down to the sub's escape hatch.
35:20With a concentration of carbon dioxide rising with every breath, the air in the sub was
35:26becoming more poisonous by the minute.
35:37Sibitsky had to succeed, and quickly.
35:41On this mission, there was no room for error.
36:24When Sibitsky got down there and started
36:26to work really hard dragging that heavy cable around, he was breathing more air, which meant
36:32he got nitrogen narcosis.
36:34He became physically fatigued and very confused, almost drunk.
36:44The rescue was on the verge of collapse.
36:46When back on deck, Momsom stepped in.
36:53Momsom knew exactly what Sibitsky was going through, so he talked him through it, step
36:59by careful step.
37:05Momsom helped Sibitsky gather his thoughts and overcome the effects of nitrogen narcosis.
37:13At last, he was able to clip the cable on.
37:24The first stage of the operation was complete, but the hardest part was still to come.
37:31Now it was time for Momsom's chamber to be put to the test.
37:36The crew of the rescue chamber climb in for their risky adventure.
37:39The idea is to lower it onto the sunken sub, make it fast to a hatch, open the hatch, and
37:44bring the survivors up into the rescue chamber, so beneath the surface it sinks, for life-saving
37:50without precedent.
37:51This occurs a little more than 24 hours after the United States submarine Squalus sank while
37:56making a practice dive off Portsmouth.
38:00Lowered by a support cable, the chamber began its descent.
38:07Although it had never been tested in a real rescue situation, it was the only hope for
38:13the men in the Squalus.
38:21But would it work, would the seal hold?
38:34At 12 noon, the chamber landed over the escape hatch.
39:00The seal held.
39:1330 hours after the Squalus first hit the bottom, the unbelievable had happened.
39:18A rescue mission had reached the submarine.
39:25Carl Bryson watched the first eight men get into the bell.
39:29They were the crew members most affected by the cold and poor air.
39:40It was essential to get the weakest to the surface first.
39:43No one knew how long the rescue would last.
39:46If the weather would hold, or indeed, if the bell could actually manage the four journeys
39:51needed to lift the survivors to safety.
40:00Under Momsom's orders, the bell was raised, carrying the first survivors.
40:09Valves letting air to the ballast tanks.
40:12And inch by inch, the chamber rose.
40:17Guided by the cable to the ship above.
40:27For now, everything seemed to be working perfectly.
40:37At last, the bell made it to the surface.
40:47There it is, bubbling and breaking the water.
40:49The dramatic sight.
40:51Sudden appearance of the diving bell.
40:53All the rescue power of the Navy mobilized.
40:56And here is the climax.
40:57The rescue chamber coming up from its first descent.
41:04Hoist it up.
41:05What's in it?
41:06There are anxious wives and families waiting tensely.
41:09Open it up.
41:11And then out they climb.
41:12Survivors.
41:13The first one.
41:15So weakly has to be helped.
41:17After being entombed for 24 hours at the bottom of the sea.
41:21One after another.
41:22Seven in all are brought up in this first trip of the rescue chamber.
41:27It was a historic moment.
41:28For the first time ever, men had been rescued from a submarine on the sea floor.
41:34And in that instant, everything Monson had worked for was validated.
41:39But it was far from over.
41:41There were still 25 men to be brought up.
41:43The sub was freezing and the air was getting fouler by the minute.
41:48There was no time to waste.
41:52The next two dives went without a hitch.
41:55With 18 more men being brought up safely to the surface.
42:01The chamber was sent back down to the Squalus for the final time.
42:05A little before 8pm.
42:08For Carl Bryson and the last few survivors.
42:11Struggling against rising carbon dioxide.
42:14And the constant threat of chlorine gas.
42:17It seemed to be the end of their ordeal.
42:20So we were all up there and waiting.
42:27Seemed like it took hours.
42:29Man it was cold.
42:30And the air was horrible.
42:31It was getting worse all the time.
42:45How did it feel getting in that bell?
42:47Well, it felt good to get in the bell.
42:50But then when it jammed, it didn't feel so good.
43:02The bell had only risen about 10 metres when it stuck fast.
43:09The main cable running down from the bell to the sub below had jammed.
43:24Diver Walter Squire was sent down into the water to free the stuck cable.
43:29He made his way down tentatively.
43:43Squire fumbled around for the cable a few metres below the bell.
43:47He tried to free it, but it wouldn't budge.
43:50So on Momsom's orders, he cut it.
43:58Now the full weight of the nine and a half tonne chamber was hanging from a single support cable running
44:05to the ship above.
44:10Just when it seemed the worst was over, the diver returning to the surface noticed something disastrous.
44:16The cable left holding the chamber had begun to unravel and snap.
44:21And the bell was now dangling from a last single strand.
44:26The men's lives were literally hanging by a thread.
44:31Afraid that this last strand would break, Momsom had to order the chamber gently lowered back down to the seabed.
44:37So just moments from triumph, the rescue had stalled.
44:56Momsom had to drop us back down in the mud.
44:58We were up to 150-foot level then.
45:09And we dropped us back down because if that cable had parted and then the exhaust cable and the air
45:17cable, then we would be lost.
45:24With the last of the survivors trapped inside the bell, Momsom came up with an all or nothing plan.
45:30It was highly risky, but it was their only hope.
45:35He reckoned if the operators inside the bell could carefully open the valves and blow more compressed air in, they
45:42could control its buoyancy.
45:44And his gamble was that they could make it weightless, neither rising nor sinking.
45:49If it worked, it would be light enough that it could be carefully hauled up, hand over hand.
45:56If it didn't, the cable would break and the men would be lost.
46:09He told MacDonald to blow for 10 seconds, you know.
46:16So MacDonald would blow the lower compartment.
46:25Then he'd blow 20 seconds.
46:44Finally, they pulled us clear of the mud and they had all these people up on the deck pulling this
46:52thing by hand.
46:52And we got up to about 150 feet and we went right to the surface like that.
47:00One of the greatest rescues in the annals of the sea.
47:03Men saved from the sunken submarine smallest off Portsmouth, New Hampshire.
47:08Everyone of the living brought out alive.
47:10In the history of the sea, a sunken submarine represents the depth of terror and horror.
47:15So this rescue represents a height of glory.
47:20And we got to the surface and I was frozen, man of man.
47:31I'll tell you, we were lucky, really lucky.
47:36And we had the right people in the right place at the right time.
47:45And that makes a difference.
47:53Monson had done it.
47:55It saved the lives of 33 men.
47:59The rescue of the crew from the squalas showed for the first time that something really could be done for
48:05men trapped on the ocean floor.
48:08It was a pivotal moment in the history of undersea exploration.
48:13The squalas rescue, carried out under the glare of the world's press, had put submarine safety firmly on the agenda.
48:22And within six months of the squalas sinking, the US Navy had offered the diving bell plans to 13 other
48:29countries in a bid to make submarines safe around the world.
48:38As a proven success, it was adopted by other navies.
48:46And even today, a version of the rescue chamber is still in use.
48:54It's called the McCann Chamber, named after Monson's successor in the development programme.
49:07Thanks, mate.
49:09I'm here, courtesy of the Italian Navy, to take part in a submarine rescue training exercise.
49:13I'm going to go down here in a McCann Bell, which is essentially the same piece of kit as used
49:18on the squalas rescue,
49:19to go down to a submarine at 40 metres and see what it was really like for those rescuers and
49:24for those men from the squalas.
49:26Thanks very much.
49:38Now we change programme.
49:40Yeah.
49:43Hey, we're free.
49:44So.
49:46Very good.
50:00So I can feel the pressure increasing now.
50:04Yeah.
50:04And that's because the water is coming in the lower part of the belt and squeezing all the air into
50:12this part of the tank.
50:13Right, yeah.
50:17The bell is noisy.
50:18It looks primitive.
50:20The air pressure varies wildly as you go up and down.
50:23But it works.
50:24The Italians see it almost as an elevator that can run back and forth from the surface to the seabed.
50:46It's fantastic to think that a design which is essentially from the thirties is still used today.
50:54And it's not just the Italians.
50:56The Turks, Indians, and the US still use essentially the same design as Momsom's original bell that triumphed in the
51:04squalas rescue.
51:07It's really surreal actually, because there's the submarine.
51:10I mean, there's the top of the submarine.
51:12We're 40 metres in the bottom of the sea.
51:26It just feels amazing, going down to the submarine, whilst on the bottom of the sea.
51:38Oh, wow.
51:41Hey, thanks for this, guys.
51:42On your submarine.
51:43OK, thanks very much.
51:45Thank you, my commander.
51:46Wow, thank you.
51:47Good Italian espresso coffee served at 40 metres on the bottom of the med.
51:53I'm going to remember this next time I'm diving on scuba and I'm at 40 metres and freezing.
51:58Dry, good coffee.
52:00Fantastic company.
52:01Here we go.
52:02Here we go.
52:08The squalas rescue was a turning point in the development of underwater technology.
52:15New devices were pioneered that led to some remarkable equipment, like this one atmosphere diving suit.
52:25In one of these, a diver can work hundreds of metres down on the ocean floor, allowing the construction and
52:31maintenance of many of today's most ambitious engineering projects.
52:35Like North Sea oil platforms and the undersea pipelines leading from them, which run hundreds of miles along the ocean
52:42floor.
52:43These developments would have seemed impossible before Momsom's triumph.
52:50After the squalas rescue, Momsom was promoted to commander and his prestige in the Navy just rocketed.
52:56He used his influence to launch a whole new era of underwater technology and he became the father of modern
53:03diving.
53:04One of his most significant contributions was the development of new mixed gases for deep diving.
53:10By replacing the nitrogen in the air with helium, he completely eliminated nitrogen mycosis.
53:17And that meant that professional divers like myself can dive deeper, we can have shorter decompression times, and our underwater
53:25work is just safer.
53:28In the 60s, Momsom's son, also called Charles, was a real chip off the old block.
53:34He carried on the family tradition by developing the mini-sub Alvin,
53:38seen here looking for a hydrogen bomb lost at sea after a mid-air collision involving a B-52 bomber.
53:50Since Alvin was first designed, mini-subs have become lighter and more manoeuvrable, with ever more specialised functions.
53:59Nowadays, they are used all over the world, both by navies and civilian contractors.
54:08As well as submarine rescue and training, they are used for things like investigating wrecks, searching for lost aircraft, inspecting
54:16marine structures, and even filming the secret habits of deep-sea creatures.
54:24And one man's vision of what was possible beneath the sea helped pave the way for technology like this.
54:33Momsom was a true pioneer.
54:36He revealed to the world that hugely complex diving operations can take place deep below the surface.
54:43The rescue of the Squalus gave people confidence as they dived ever deeper into this alien world.
54:54Momsom gave hope.
54:56So should things go wrong down here in the abyss, we know that help can be on its way.
55:05After a lifetime dedicated to the safety of men at sea, Momsom died in 1967.
55:14In 2004, the Navy paid him its highest honour and named a destroyer after him.
55:24As for the Squalus itself, it was salvaged from the deep in the months after it sank.
55:34Recommissioned as the sailfish, it fought through the Second World War.
55:42Her conning tower is still preserved at Portsmouth Navy Yard as a lasting tribute to the men who served on
55:48her.
55:53How does it feel to be on here now, Carl?
55:56Well, it brings back a lot of memories.
55:59I lost some very close friends on this boat.
56:15It was a sad thing. It was a heavy price to pay.
56:21Do you think it gave you a unique perspective on life itself?
56:25Oh, yes. Oh, yes.
56:27Well, as I say, I was always lucky. I was lucky since then.
56:32I was very lucky. I married a wonderful woman.
56:35I got three wonderful children and six wonderful grandchildren.
56:40I can't get much luckier than that.
56:44If Swede Momsom was here today, what would you say to him?
56:48Thank you, Swede.
56:50You betcha.
56:53I couldn't emphasize my gratitude enough, believe me.
56:59I have a medication that I take in my room.
57:04And I have a picture of Swede about so big up on my book.
57:09And when I take the medication, I always say,
57:13thank you, God, and thank you, Swede.
57:16Never.
57:28The role of the shipyards of the Clyde in the American Civil War,
57:32coming up next on BBC Four in the ships that made the Commonwealth.
57:49You know, the world is still there, right?
57:58I love you.
57:59I love you.
57:59Let's go to subscribe to my channel and find a link.