Authors: Edward L. Beach
“Lookouts,” one of them said through stiffened lips to Taylor. This too was part of the regular routine.
“Okay,” responded Taylor. “Get your coffee and come on back here.” The two men shambled stiffly off in the direction of the crew's mess hall, fumbling with parka strings and zippers.
Again the loudspeaker blared. “Clear the bridge! Dive! Dive!” Almost simultaneously the diving alarm sounded twice: two raucous blasts transmitted on the ship's general announcing system to all compartments. The chief of the watch, now standing before his diving control console, had forsaken his built-in stool. Alongside him stood Curt Taylor. Both of them kept their eyes fixed on the hull opening indicator panel, which showed two red circles and a series of dashes. This was the successor to the old “Christmas tree,” with its red and green lights, which could never be positively and clearly interpreted under conditions of night adaptation when the only light permitted was red. The chief, fingering a switch on his diving panel, glanced inquiringly at Taylor.
“Shut the induction,” said Taylor. The chief flipped the switch. One of the two circles vanished, was immediately
replaced by another of the dashes. The two men continued to watch the panel, relaxed ever so slightly when the last circle changed to a dash. “Straight board, sir,” said the chief to Taylor, unnecessarily loudly because Taylor was standing right beside him, and unnecessarily in any case since Taylor was also looking at the board. But again, this was part of the routine. Not only was Keith in the control room, so were a dozen other members of
Cushing
's crew. All of them were vitally interested in the proper conduct of a dive.
“Open the vents,” said Taylor. The chief's practiced fingers flew across another row of switches on his console. A series of red dashes in a second indicator panel changed to circles, and simultaneously a faint noise of rushing air could be heard. A pair of khaki-clad legs appeared in the bridge access trunk, followed immediately by dungaree-clad legs. Their owners, similarly garbed in dark green foul-weather parkas, with faces reddened from the exposure to the elements like those of the lookouts preceding them, stepped into the operating area around the diving panel.
“Hatch secured,” the one in khaki said to Taylor.
“Aye,” responded Taylor. “I'll take the dive, Howie.”
“All right. I'll pass the conn over to you after you get her under.” Turning to Leone, the officer of the deck said, “Bridge secured, Captain. All clear topside. We're still on the same course, one-two-five true, speed fifteen. I'll pass the conn over to Curt as soon as he's ready.”
As Keith acknowledged the formal report from Lieutenant Howard Trumbull, officer of the deck, he could feel the slight downward inclination of the submarine. Bow and stern planesmen were sitting in their seats near the forward bulkhead of the control room, facing an impressive array of dials in their carefully designed instrument panel. Extending from the floor between the legs of each was a stubby column topped with a steering wheel minus its top quadrant, patterned after the control columns in aircraft and designed to fill almost the identical purpose except that they could be, and frequently were, operated independently. The man on the left, in fact, had already pushed his control column forward. “Stern planes on fifteen dive,” he said to Curt Taylor, who had moved over and was now standing behind him.
“Three degree down bubble,” said Taylor. He turned to the man operating the right-hand column. “Put your sailplanes on full dive,” he directed. Obediently, the man pushed his control stick all the way forward, held it there.
The deck tilted farther under Keith's feet. There was more sound of air venting from the ballast tanks. The depth gauge quivered, began to show increased depth, and the log speed indicator remained fixed at fifteen knots as the steady throb of
Cushing
's single propeller drove her mighty hull down and forward.
Keith's mind flipped backward. In some ways this was so much like going to sea on a war patrol. But yet so different, and in the space of only fifteen years! In departing from Pearl Harbor,
Eel
had traveled almost entirely on the surface to her operating area. Except for daily drills and the ever present necessity to dive on appearance of a patrolling aircraftâall the more likely to be encountered as she approached enemy watersâshe tried to stay on the surface in order to make more speed. The
Cushing
, by contrast, could make higher speed submerged. Furthermore, she could manufacture her own atmosphere from seawater, and dispose of unwanted gases, such as carbon dioxide and carbon monoxide, overboard. She was totally divorced from the surface, had no need for it, except for entering and leaving port. She could do everything she had to do submerged, far better than on the surface. She would dive as soon as she cleared the shallow water, and remain submerged until return. She would surface only if necessary.
Eel
had been a much smaller ship than
Cushing
, but she had dived and surfaced more frequently, and her dives were more complicated to execute. There were diesel engines, up to fourâfive counting the dinky, or auxiliary charging engineâto shut off; for each, as it rolled to a stop, there were two exhaust valvesâone hydraulic and one hand-operatedâto be closed before the submarine went under (but not before the engine stopped revolving). And there were two big spring-loaded air inlet ducts to be closed in each engineroom with a great clang of metal.
Shutting the even bigger air intake valve, hydraulically operated, was one of the principal control room functions, to be accomplished after the engines had stopped and before the valve itself, located as high as possible under the after part of the
bridge deck, went under. Then, as soon as the last hull opening was closed, usually the bridge hatch, there was always a great whistling and roaring as the control room bled high-pressure air into the submarine to confirm that she could hold air pressure and therefore was indeed watertight. A logical practice for a slow dive, right out of overhaul for instance, when some overlooked repair or some shore-based workman's carelessness might have left an important hole unsealed. But in a fast dive the ship was half under before the last closure, the hatch or the induction valve, was shut, and there was no way to stop her downward momentum. If there were in fact a large hole, such as an open and unnoticed torpedo-loading hatch or a stuck-open air induction valve, the first sign of danger would be an increase in air pressure as the sea came in.
An artificial increase in air pressure during the act of diving would only delay detection of the first sign of danger, not help reveal it. But this had apparently not struck the submarine force authorities of that time. The whoosh of air, accompanied by pressure on the ears, had become part of the symphony of diving, welcomed uncritically by all because it signified orderly accomplishment of an orderly procedure.
In the
Cushing
things were much simpler. Air bleeding, with its attendant noise, had been abolished. Not only had the disadvantages been at last recognized, there were many fewer hull openings to close and hence less reason for a last-minute air test. There were no air-breathing diesel engines to shut off, no switching to electric motors for submerged propulsion, no haste to get down before an enemy aircraft could get on top of her with a bomb. In her engineroom a dive caused no change of any kind, except that the ship tilted very slightly downward for a short time and then leveled off again. To maintain the ordered speed, the engine throttleman might have to adjust steam flow to the turbine, that was all. If she went deep enough, he would have to close the throttle slightly, to match the reduced resistance to
Cushing
's forward motion.
Something all submariners know: the laws of physics hold immutable, even though sometimes they seem to place effect before cause. A great deal of the power necessary to drive a ship through water is wasted in turbulence, visible in the form of wake astern and waves radiating outward from her passage. When a
modern submarine is operating at shallow depth with any speed at all, there is nearly as much water disturbance as if she were actually on the surface, an incongruous and startling thing to any observer in the vicinity. But as the submarine depth increases, there comes a point when the pressure of the sea no longer allows turbulence to be formed. At this depth, and deeper, there is no surface evidence of her passage. The depth at which this occurs is dependent, of course, on speed; the faster the submarine is going, the greater her depth must be.
Several other things happen at about the same time, among them a sharp reduction in propeller noise, but most noticeable of all is a sudden increase in speed. The engines now have but one outlet for their horsepower: driving the submarine forward. She is no longer creating waves or turbulence. She has been freed from surface effect, which means there is now reduced resistance to her forward motion. And so she speeds up. To the throttleman in the engineroom, this is evidenced by an increase in propeller speed, and he automatically closes the throttle slightly, reduces the flow of steam to the turbines, holds the rpm to the ordered figure.
Another factor is propeller slippage. Defined as that percentage of propeller revolutions not converted into forward motion, slippage is essentially another measure of power wasted in turbulence. Designers have long known that the deeper a propeller can be, the less its slippage (another reason why the paddlewheel lost out). A deeply submerged submarine experiences virtually no slippage at all. Her propeller speed becomes precisely a measure of her speed through water. The distance she travels over any given time may be calculated with almost mathematical exactitude by multiplying the pitch of her propeller by the number of revolutions it has made, as shown on the revolution counter in the engineroom. For all these reasons, a deeply submerged (and properly streamlined) submarine can go faster than she can on the surface. This is true despite her larger displacement when submerged.
“Make your depth two hundred feet,” said Keith to Curt Taylor. It was an unnecessary order, but part of the ritual. Diving officers (and all planesmen as well) had already been instructed to keep the ship one hundred feet off the bottom, slowly increasing depth as the bottom fell away until ordered cruising depth, four hundred feet, was attained. The drumming noise of the surface
had ceased. Air was no longer venting from the ballast tanks.
Cushing
's speed stayed rock-steady at fifteen knots, her angle downward at a comfortable three degrees, her depth gauges slowly creeping upward toward the ordered depth. As they neared it, the planesmen without orders pulled back on their control columns, the ship leveled out, and Taylor turned to Keith.
“Two hundred feet, Captain,” he reported. “Fifteen knots, course one-two-five true. There's a hundred and five feet of water under our keel. I have the dive and the watch, and will take over the conn as soon as Howie is ready to turn it over.”
“You've got it, Curt,” said Trumbull, who had been standing unnoticed in the background. “Course one-two-five true. Speed fifteen. Ordered depth two hundred feet, increasing to four hundred cruising depth. There is one ship in sight, well clear to port. No land in sight.”
“Aye, Howie.” To Keith, “I have the conn, Captain.”
It was all so businesslike, so controlled, so routine. There was very little of the thrill of the old-time dive, the split-second timing. Nor was there any need for a stopwatch in the hands of a quartermaster to monitor the time it took to get under.
Fast dives had been necessary in the old days, because a plane coming at two hundred miles an hour could bring disaster in a very short time.
Eel
had regularly submerged in less than thirty seconds. It had taken the much larger
Cushing
twice or three times that long, but diving from under aircraft attack was no longer the problem it used to be. In 1961, with a ship like the
Cushing
, cruising on the surface was for leaving and entering port.
With
Cushing
once more on even keel, Keith left the control room, walked thoughtfully forward to his own stateroom. He would keep
Cushing
on course one-two-five until clear of the hundred-fathom curve. Then he would change the ordered course to due east, and in about three days more, when clear of the Grand Banks, he would order it changed again, to northeast.
Cushing
would find her way by sound alone, probing constantly by fathometer and forward-beam sonar against the possibility of an uncharted bottom anomaly, or another ship. It was another ship which worried Keith the most. The ocean floor had been well enough charted of recent years to assure against sudden
surprises standing on the deep seabed, but the possibility of another shipâa submarineâwas a different matter. No U.S. or NATO submarine would be routed through the vicinity of
Cushing
's plotted positions, but there was no telling what the submarine of another nation might do. Which was another way of saying that a Russian submarine, routed by its own navy department without relation to anything planned by that of the United States, might conceivably blunder into
Cushing
's path. And if the other sub happened to be at the same depthâanother remote chance in the huge world oceanâthe collision could be catastrophic. But this was not something one worried much about. The mathematical chances against such an incident occurring were astronomical.
In the event of war, of course, it would be different, but even so the main danger of collision would be with submarines on one's own side. Enemy convoys or task forces could be considered a magnet drawing all submarines in the vicinity. Even as far back as World War II, when diesel-driven submarines pursued enemy convoys on the surface and dived for attack after having attained a favorable position, the problem had been recognized. Coordinating operations so as to avoid the danger of collisions while submerged, orâeven more to be dreadedâaccidentally torpedoing a submarine on one's own side as it also sought a favorable attack position, had occupied much thought and careful planning. Ultimately, if submarines continued to increase in number, there might come a time when the danger of collision would require measures similar to those controlling airplanes in the sky. But this time was far in the future. Keith gave it only a second thought, shrugged his shoulders, opened the letter from Peggy. As he read it, his forehead furrowed.