Thirty Fathoms Deep

by Ellsberg, Edward

  “Try to sleep. Tomorrow you’ll be surprised!” He went out, closing the door.

  Chapter 6

  “Dere, Mistuh Porter, Ah jes knowed you’d be eatin’ agin someday!”

  “Don’t you kid me, Fitz,” said Bob, smiling a little sheepishly after his second cup of coffee.

  “Don’ worry, dey ain’t nobody knows it ’cept de skipper an’ me. You dun got ovah it quick. But Ah reckon you’ll want me to press dem clothes. Dey shuah look as if somebody’d slep’ in ’em!”

  Bob looked at his badly wrinkled jacket and nodded.

  “You can have ’em right after breakfast, Fitz. And remember, you’ve got to forget this when we get back!”

  A broad grin from Fitz assured him that it was already forgotten.

  Still a little pale and weak, Bob changed his clothes and went out on deck. It was a glorious June day; a mild breeze fanned the ship, and sailors lounged against the deckhouse, or worked in little groups on the fantail. Abreast the door to the galley, leaning against the starboard rail, were the divers. Bob sauntered down the passage to them.

  Tom Williams, a broad-shouldered six-footer, towered over the group. Bill Clark, heavy set but shorter, puffed away on a short pipe. Joe Hawkins and Frank Martin, both rather slight figures compared to their brawny shipmates, seemed to be engaged in making fun of Clark, who very seriously was arguing with them. Williams, Hawkins, and Martin, all of whom had been chief petty officers, still wore their old uniforms, including their visor caps with the Navy’s fouled anchor, but Clark, who had gone into the Reserve as a boatswain’s mate, first class, had on only a sailor’s white hat, and it was over this that the discussion seemed to centre.

  It stopped, however, as Bob came up.

  “Hullo, Bob,” said Williams, greeting him with the cordiality born of their previous summer together. “We been tryin’ to convince Bill here that the reason he was never made chief in the old outfit while we all were, was because we were better sailors ’n him.”

  “Belay that, Tom. It was just coz I was a better man, Bob, than any of ’em!” said Clark emphatically. “Here these lubbers’d go down on a diving job ’n get in trouble ’n have to rescue each other. Then when they come up, they’re all heroes ’n get promoted. Here I am, the best diver in the lot, made more dives ’n any of ’em. When I get in trouble, I get myself out ’n never say nuthin’ about it on the top side. Why, if I got a promotion each time I rescued myself from a tight hole, the way these gobs do for each other, I’d be an admiral by now instead of a boatswain’s mate!”

  “You’d make a sea-goin’ admiral all right, Bill, ’specially with that pipe of yours,” said Martin unabashed. “Too bad you were so modest about tellin’ Lieutenant Carroll about all those rescues. Still I s’pose it was safest. If he’d learned what a dub you were on the bottom, always havin’ to be rescuin’ yourself, he’d a kept you on deck where a boatswain’s mate really belongs.”

  They all laughed.

  “C’m on into the tank. We’ll be more comfortable there. I’m tired of standing,” said Martin.

  They went through a door in the starboard bulkhead, ducked one by one, and slipped through a small round door into a cylindrical steel chamber about six feet in diameter, then through another similar door into the inner compartment. Bob looked round wonderingly. Several valves lined the outboard side, while a gauge hung overhead.

  They sat down on some blankets covering the wood deck inside; Bob, however, had a bench.

  Joe Hawkins noted the young man’s curiosity at the strange shape of the room.

  “I guess you don’t know much about diving, do you, Bob?”

  Bob shook his head.

  “Well, this is the ‘iron doctor,’ so far as us divers is concerned. The technical sharks call it a recompression tank. It’s built to stand high pressure just like a boiler. That’s why it’s cylindrical and has got dished heads. And those round doors we came through, they’ve got to be small so as not to weaken the end bulkheads too much.”

  “D’ye know what the pressure’s for?” asked Martin.

  “I’m sorry, but I don’t,” replied Bob.

  “Well, I guess I’d better start at the beginning then,” said Hawkins. “It’s a long story. You lads can interrupt me if I get it wrong anywhere.”

  They settled themselves comfortably, Bob on the stool facing the sailors who sprawled out on the deck, their backs against the steel cylinder.

  “Well, you see, Bob,” Hawkins began, “diving isn’t what most people think it is. They think we wear a diving-suit to keep from getting wet and getting drowned, but that isn’t what really bothers us under water. That is, not much anyway. It’s the pressure that causes the trouble in diving. Now y’ know water’s heavy. That’s simple; it’s the weight of the water the Lapwing displaces that’s keeping her afloat, and the Lapwing is no feather. Well, anyway, the water’s got plenty of weight, and when you go down in it, it presses against you with a force equal to nearly one hundred and thirty pounds per square foot for every two feet you go below the surface. Let’s see, how deep’s that ship we’re going after?”

  “A hundred and eighty feet,” responded his much-interested auditor.

  “A hundred and eighty feet,” repeated Hawkins slowly. “Let’s see what that makes.” He figured for a moment with a pencil on the side of the tank. “To be exact, it’s about six tonnes to the square foot. All right. That means that down where that ship lies, the sea is pressing over each square foot of her with a weight of six tonnes. Now let’s say a diver gets down there. There’s the same pressure from the sea all over him. Hey, Tom, what’d Lieutenant Carroll say the average area of a man’s body is?”

  “Well, it’s worse for me ’n it is for you — I’m bigger — but it runs about fourteen square feet on the average.”

  “Good enough. Take fourteen square feet,” continued Hawkins. “That’s six tons on each square foot times fourteen,” he thought a moment, “eighty-four tons. That means the sea is pressing down on the diver’s body with a weight of eighty-four tons. I guess that’s as much as a sixteen-inch gun weighs. Just imagine trying to support the breech end of a sixteen-inch gun on your chest.”

  Bob tried to imagine it. It did not seem possible.

  “It’d mash you flatter ’n a pancake all right, but that’s just what the diver’s got to support down there, and here’s how he does it. As he goes deeper and deeper, you force air down to him through his air-hose at a pressure that has to be a little greater than the pressure of the water where he is. The air comes into his helmet, and he breathes it in under the same pressure. It goes to his lungs, puts them under pressure, and his blood carries the pressure all through his body to every part of it. Let’s see, what can I compare him to?”

  “A tyre,” suggested the boatswain’s mate.

  “Yes, I guess that just fits. Take one of these motor-buses, for instance; they’re big and heavy but the weight is held off the road by the air inside the inner tube. As long as that’s blown up with enough pressure, the tyre’s rounded out and carries the load. But if the tyre springs a leak and loses its air, then down comes the weight of the car and flattens out the tyre.

  “Well, a diver’s the same way. As long as he’s blown up with a pressure equal to the water pressure, he’s all right, but if his helmet loses the air pressure inside it, down comes that eighty-four ton weight like a trip hammer and mashes him as flat as any blown-out tyre!”

  Bob whistled.

  “That’s happened plenty of times,” added Williams, “and the water don’t have to be so deep either. While we’re workin’ on the S-51 a diver workin’ in only thirty feet of water in the East River was ‘squeezed’ to death when his tender up on deck carelessly uncoupled his air-hose an’ let all the air blow out of his helmet. That diver was jelly when they hauled ’im up. Most of his body was squeezed right up into his helmet.”

  “You see how it is, Bob. If you want to work in deep water, you’ve got to work under
high pressure. And that’s the real danger in deep-sea diving. Diving isn’t anything new, you know. There’s been plenty of treasure ships sunk before, some of ’em in water that wasn’t so deep, and divers have been working on ’em for a couple of centuries back. But the strange thing about it was that if they stayed down long enough to do anything, when they came up they got terrible convulsions, and those of ’em that didn’t die usually got paralysed for life. Of course, that didn’t make diving exactly popular, but people’ll try lots of things if there’s enough in it, and they kept on struggling after these sunken wrecks. None of ’em ever lived very long to enjoy the gold when they got it though, and they laid the trouble to all sorts of superstitions. The disease got the name of ‘the bends’ from the way it caused the victims to double up in pain.

  “And that’s the way the thing stood until all sorts of engineering jobs and bridge foundations turned up that required men to work under air pressure. Then the doctors turned to and started to find out what caused ‘the bends’ and how to avoid ’em. And they discovered a curious thing.”

  Bob listened eagerly, but he was interested to note that the other divers were just as much absorbed in the recital as he was. Evidently Hawkins had studied the theoretical side of diving as well as practising it; his shipmates were listening as if most of it was new to them.

  “Well, the surgeons found out there was a difference between breathing air the way we do, and having to breathe it under pressure the way a diver does. I s’pose you learned in school what air’s made of?”

  Bob nodded. “Oh, yes, we had it in our physics course. Air’s about one-fifth oxygen and four-fifths nitrogen.”

  “Yes, that’s it,” Hawkins agreed. “Now look what happens. When we breathe here, the oxygen we get in each whiff is taken up through the lungs by the blood and acts chemically on it for all sorts of purposes that our bodies need. But the nitrogen is just inert, it doesn’t do anything except dilute the oxygen, and it is breathed out again when we exhale. That’s what our bodies are accustomed to.

  “But that ain’t what happens to a diver. Instead of breathing just ordinarily as we’re doing here, he’s breathing air that’s under high pressure. And under that pressure, the nitrogen entering his lungs, instead of being all exhaled, is forced by the pressure to dissolve in his blood. Now the deeper a diver goes the greater the pressure gets, and he consequently soaks up the nitrogen faster; the longer he stays there, the more he gets. The nitrogen doesn’t do anything but just dissolve in him. Of course, he doesn’t feel it; the old-time divers didn’t even know it was happening.

  “So there he is, feeling more or less all right until it’s time to come up, and then the trouble starts. What’s the best illustration of what happens? I got it! He’s like a ginger ale bottle.

  “Supposing we had a bottle of ginger ale here, and I’d hold it up to the light. It’d be a nice clear liquid. There’s a gas, carbon dioxide, dissolved under pressure in the ginger ale, only we don’t see it. Why? Because the pressure keeps it dissolved. Now supposing Tom here rips the cap off the bottle. What happens? The pressure is released as soon as the bottle’s opened and the gas starts to come out of solution. Result? The ginger ale gets full of bubbles and froths out of the bottle!

  “Well, Bob, that’s just what used to happen to the divers. When they came up, the pressure they were under disappeared and the nitrogen dissolved in their blood, without any pressure to keep it dissolved any longer, came out and formed bubbles. And the more gas they had in ’em, the bigger the bubbles were. The bubbles would clog their arteries and veins, stop the circulation and give ’em ‘the bends.’ If they hadn’t been down over long, the bubbles’d gradually work out and they’d recover, but if there were very many, they’d die. Some of the bubbles’d lodge in their spinal columns, and that’s what gave ’em paralysis even if they managed to live.”

  “So that’s why deep diving’s so risky!” exclaimed Bob. “I’d always thought it was because of devil fish and sharks that diving was dangerous!”

  “Yeh, them’s the fairy tales they feed the kids,” said Martin. “That’s a hot one! Any of you lads ever bothered by sharks?”

  “I saw one once,” Williams replied, “when I was workin’ off the Delaware Capes. He just swam round but didn’t bother me none.”

  “I suppose that’s the way she goes,” Hawkins continued. “What a diver’s actually up against ain’t bad enough for these wild tales by people who ain’t never seen a diver. Well, anyway, it’s bad enough for the divers. But getting back to my story, when the doctors found out that bubbles was what was causing ‘the bends’ they just about had the answer.

  “Instead of letting the diver come right up when he was done, the thing to do was to bring him up only a short way so as some of the nitrogen would come out of solution, but still there’d be pressure enough left to keep any bubbles from forming. Then after a little while there, haul him up a few feet more to let some more gas work out, and so on all the way up — taking him up by stages with a stop at each stage to let him ‘decompress’ as they called it. And that was the cure. They worked out the decompression-tables, and if you don’t stay down too long and come up according to the tables, you won’t get ‘the bends’ — not bad, anyway.”

  “That’s right, mates,” added Bill Clark, “but the distressin’ thing about it is that you have to put in about twice as long comin’ up as you spend on the bottom, and if the water’s cold, the way it was on them subs, you sometimes wonder if you wouldn’t sooner have ‘the bends’ than freeze to death on the way up!”

  “It’s a tough life, any way you take it,” Martin admitted. “I’m glad this boat’s gonna be in a warm climate. I’ve had enough of divin’ in ice water.”

  “That’s some relief, anyway. I’m looking forward to it as a change myself,” agreed Hawkins. “It’ll be a pleasure not to have to put on three suits of woollen underwear and dress up like a polar bear before taking a dip.”

  “And doesn’t anyone get ‘the bends’ anymore?” asked Bob.

  “They sure do,” replied Bill. “That’s what this tank’s for and that’s why we call it the ‘iron doctor.’ If the boys get ‘the bends’ now, we clap ’em into the tank and put ’em under pressure again as fast as possible. That recompresses the bubbles an’ relieves ’em. Then we lower the pressure by steps an’ ‘decompress’ ’em again. It’s a great thing.”

  “You’ll notice this is a two-compartment tank,” explained Tom. “That outer chamber with the double doors is so that anybody can pass in or out to help the man under pressure in here. That’s an airlock. You can get into it from the outside, close the outer door, run the pressure up until it balances whatever pressure’s in here, then open the inner door and crawl into this chamber.”

  Hawkins stretched himself.

  “I think I heard eight bells. Feels like chow-time to me.” He got up and crawled out, followed by the others. Bob, his head somewhat in a whirl at what divers really had to combat, squeezed through the airlock doors out to the deck. He took a deep breath; the air in the ‘iron doctor’ had been getting stuffy. Thoughtfully he walked forward and entered the cabin.

  Chapter 7

  Day after day, under a sky growing bluer and bluer, the Lapwing stood on to the southward. The weather grew warmer; they entered the Gulf Stream, and it became uncomfortably hot and humid as the sea temperature took a sudden jump. Blue clothes were discarded; all hands came out in whites, and the scuttle-butt just outside the galley, with its ice cold water, became the popular gathering place for the crew.

  Bob wandered through the ship, exploring every hold, getting acquainted with every compartment. On deck he found it hot enough, but in the boiler rooms he marvelled how the firemen stood it, with the temperature at 120° and the flames roaring through the furnaces and radiating heat out on to the doorplates. The sweating firemen tended their burners, regulated the feed pumps, and watched the water levels in the gauges while Bob, wilting under the fierce hea
t, sought refuge by standing directly beneath the ventilator down which a stream of air rushed into the fire room — hot air from the top side but cool nevertheless in contrast with the rest of the room.

  Soaked in perspiration, his undershirt clinging tightly to his back, Bob looked round. On the port side, outboard of the boiler, was a large horizontal air-compressor, newly installed to supply air to the diving-lines. Over it, bolted to the side of the ship, were a number of huge steel bottles, the high pressure air-banks, which were charged up to a pressure of 2400 pounds per square inch by a special four stage torpedo air-compressor. Bob looked curiously at them. Both compressor and bottles had come from a dismantled submarine, where they had formed the reservoir to supply air for the crew to breathe while she ran submerged, or to blow the water quickly from her ballast tanks and come up in case of emergency. Lieutenant Carroll had installed them on the Lapwing as a reserve supply of air to feed the divers in case the compressor broke down. Coming up from deep water is a slow process; Carroll could take no chances of letting the air supply stop if the machinery failed.

  Outboard of the forward boiler, Bob noticed a large steam pump with a brightly polished copper air-bell on one end. He squeezed by the boiler to inspect it. A large sea-valve connected its suction directly to the skin of the ship; its discharge line led to the deck overhead. Evidently it was the fire-pump, ready to suck seawater from far below the waterline and discharge it in large quantities to the fire-mains on deck.

  Bob crawled aft, clear of the boiler, and stood a moment beside the fireman, whose sweating body, stripped to the waist, glistened in the reflection of the flames as he opened the shutters to adjust the furnace fires. He shrank from the fierce heat which blazed out and sought shelter in the breeze beneath the ventilator. The fireman closed the door, walked over to a bucket of water against the bulkhead, lifted it up, drank several quarts, and poured the rest over his head.