In the unlikely event that Tom was wrong, that the ship was light instead of heavy, water would have to be taken in rapidly in order to keep her from broaching surface; but with the aid of sea pressure, this is always a much easier thing to do than to pump it out.
The particular problem that faced us had almost never been experienced in battery-driven submarines, for these normally operate at minimum speed while submerged in order to conserve their vitally important batteries, and any divergence from a perfect submerged trim is instantly evident. As a consequence, all old-fashioned submarines automatically stay in perfect trim, practically as a reflex action, whenever they operate submerged. Being even slightly out of trim causes difficulty in maintaining depth at slow speed. But at our sustained high speed, a few hundred tons of extra weight, or buoyancy, would be unnoticeable—until we slowed down.
Everyone in the ship was up and around during the drill period, late-sleepers among the off-watch section having been jolted into consciousness by the daily test of the ship’s various alarm systems, which had been programmed for fifteen minutes prior to the beginning of the exercise.
At the agreed-upon time, I, too, was in the control room, as were Will Adams and Tom Thamm. At my signal, Will picked up the telephone and spoke briefly to Don Fears, who, naturally enough, just happened to be in number one engine room.
Immediately, a strident voice bellowed on the ship’s general announcing system. “Control, this is Maneuvering One. We’ve lost all power, both shafts.”
I watched the engine-order telegraph indicators on the Diving Control Panel shift swiftly from “ahead full” to “stop.”
For a moment, nothing else happened, though I knew our propellers were now only pinwheeling with the ship’s motion through the water. Dick Harris, who had the Diving Officer’s watch, stepped a few inches closer to his planesman; all three were intently scanning the instruments in front of them. Seated on the padded tool box in front of the fathometer, Tom Thamm was doing the same, while two feet farther aft, Chief Engineman E. C. Rauch had squared himself away in front of his Diving Panel and crushed out his half-smoked cigarette.
Elsewhere in the ship, wherever there was a critical station, I knew that the men on watch were standing by to take whatever action might be necessary, and because this was a scheduled drill, at every station there also stood, as observers, the off-watch personnel, the senior petty officer in charge, and the officer responsible.
We had been making just under twenty knots. As the ship slowed, I knew that both Dick and Tom were watching the depth gauges and the plane-angle indications for the first sign that we were, as everyone suspected, considerably heavier than the water we displaced. We waited a long minute, as Triton slowed and her bow and stern planes gradually lost effect. Suddenly, Harris reached his hand out behind him, motioned toward Rauch. “Pump auxiliaries to sea!” he snapped.
I had not seen yet any indications of the ship’s being heavy. “How do you figure we’re heavy, Dick?” I asked.
“Mostly intuition I guess, Captain,” he replied. “There’s really no sign here yet, but I know darned well she’s heavy.”
Another minute passed. We had slowed perceptibly and now it became evident that to hold the ordered depth, the planesmen were required to maintain up angle on both bow and stern planes.
“We are heavy, all right,” I said.
From Harris my response was a tight-lipped smile, but it was Third Class Quartermaster Roger A. Miller, standing watch on the bow planes, who put it into words with a deep-toned whisper which caromed off the deck and bulkheads and brought amused smiles to everyone within earshot.
“This old hog sure has lead in her ass!” said he, as he lifted the bow planes another five degrees.
As speed dropped off rapidly, bow and stern planes soon were at the maximum angles of elevation and then, inexorably, Triton began to sink. In the meantime, Rauch, checking the rate-of-flow meter, was monotonously calling out the amount of water we pumped overboard: “5,000 out—7,000 out—10,000 out, sir—12,000 out—15,000 out.”
Dick made no motion to stop him. Triton’s speed through water had by now dropped to only three or four knots; she was still on an even keel, but the depth gauges were showing a gradually increasing speed of descent.
It was apparent soon that we should not be able to get enough water out of the ship before she had exceeded the maximum depth to which we were allowed to submerge her. Deliberately I waited as long as possible, then finally nodded to Dick, “I guess we won’t be able to catch her, Dick. Blow tanks.”
“Blow forward group! Blow after group!” Dick had the orders ready.
So did Rauch, whose fingers were already on the main ballast blow valve switches. With two quick motions, high-pressure air was roaring into Triton’s main ballast tanks. Dick waited until he saw our downward motion perceptibly reduced, then gave the clenched fist signal to Rauch at the same time as the order, “Secure the air!”
The noise of air blowing stopped. We had lightened the ship by several hundred tons, and Triton’s involuntary dive stopped well above the allowed limit. But this was not the end of the episode.
The depth gauges now started going in the other direction. Triton was rising to the surface, slowly at first and then with increasing speed. We had placed a large air bubble in our main ballast tanks which, like uncorked bottles inverted in the water, were open at the bottom and closed at the top. It was impossible to gauge the amount of air that had to be blown into the tanks so as to put the ship precisely and exactly in equilibrium at a given depth.
Having put enough air into the tanks to stop the descent, it was apparent that the ship would now rise. As she rose, however, the size of the air bubble increased as the sea pressure reduced; and as the air bubble increased in size, it pushed even more water out through the bottom of the ballast tanks, thus making Triton still lighter. In this condition, we would continue to lighten and rise faster until we reached the surface.
Once, during the war, with the old Trigger leaking badly and surrounded by Japanese destroyers listening for us to start our pumps, we had survived just such a situation by putting an air bubble in one of our tanks and then either venting it slowly into the ship (we dared not use the main vents, which would have loosed a betraying bubble of air to the surface) or blowing it carefully. With the desperate skill of emergency, for fifteen hours Johnny Shepherd maintained precise control of our depth, as the accumulated leakage of water gradually made us heavier and heavier, until finally we outlasted the enemy. We had not dared to relieve Johnny.
The situation here was far less tense. There was no enemy; we could afford to let air bubbles come to the surface. Our only problem was to control the size of the bubble in our tanks to keep from broaching surface on the one hand or going too deep on the other.
As Triton ballooned upward, I watched silently for signs of the required action. It is for situations like this that men are qualified in submarines. With approval, I saw Rauch keeping his eyes on Harris, his hand already resting lightly on the controls for the main vents. Thamm was watching, too. Triton rose at an ever-increasing pace and finally Dick gave the order: “Open main vents.”
I could hear the vent mechanism operating and all of us heard the rush of the entrapped air as it escaped from the tank. But Dick was still watching the depth gauges, “Shut main vents,” he ordered. His objective was to catch some of the air still inside the tanks in order to retain some of the resulting buoyancy. In the meantime, with approval, I noted that he had not ordered Rauch to stop the trim pump, that we were still pumping water from the midships auxiliary tanks to sea.
Triton’s rise toward the surface ceased rather abruptly. By this time, we had no forward motion through the water at all. With the ship badly out of trim, she was controllable in depth only by the constant buoyancy of her great hull, plus the variable buoyancy of the expanding and contracting volume of air in the ballast tanks. Undersea ballooning was an apt simile.
But Dick had let out too much air, for Triton was now heavy and began to sink once more; as she sank, the air bubble remaining in the ballast tanks would be further and further compressed, with the result that the ship’s buoyancy would continue to reduce and she would now progressively descend faster and faster—though slower than the first time. Dick was ready for this, however, and after we had sunk some little distance, he again ordered that tanks be blown, but for a considerably shorter time than before. Again, Triton halted her descent and began to rise; and, as she neared the surface, Dick opened the ballast tank vents and allowed most of the air to escape.
In the meantime, we had continued pumping water out of the ship. Gradually, our wild gyrations lessened as we got her correctly trimmed. With ballast tanks again full of water, no air trapped in them, Triton finally hovered, motionless, balanced precariously with her internal weight exactly equal to that of the water displaced.
It might be well to explain at this point a fact that submariners know well, but which may not be so well known to others: it is impossible for a submerged body to be so delicately trimmed or balanced that it will remain indefinitely static, neither rising nor falling. Despite fanciful tales written by people who do not know their physics, things cannot just sink part way. A submerged submarine has no reserve buoyancy; that is to say, she gains no additional buoyancy by sinking a little deeper in the water (a surface ship, passing from more-dense to less-dense water, increases imperceptibly in draft). If an eight-thousand-ton submarine is one pound heavier than the water she displaces, she will slowly sink. The deeper she goes, the greater the pressure; even the strongest hull will be slightly compressed, thus reducing the volume of displaced water and increasing the disparity between her weight and that of the water displaced. She will go all the way down until she reaches the bottom. Conversely, a submerged submarine one ounce light will ultimately broach the surface. The only exception to this rule occurs when there is a layer, or stratum, of heavier water underlying a lighter layer. In this case, the submarine can “balance” on the boundary between the two, as long as the dissimilarity continues to exist. This is known as “riding a layer.”
It is true that a submarine almost in perfect trim—as near to perfect trim as it can possibly get—might very very slowly sink in water of a certain density until it reaches a layer of water considerably cooler or more saline than the one for which trimmed, and there she will stay for a while. Ships have been known to ride thus, suspended between two layers of water of dissimilar densities, for many hours. There have even been stories about balancing a submarine so skillfully that the slight increase in displacement gained by raising a periscope would cause her slowly to drift toward the surface, and sink slowly when the periscope is withdrawn inside its bearings, but, practically speaking, such situations are rare and highly temporary.
The submarine riding on a layer will maintain depth so long as all the factors affecting her equilibrium remain exactly the same. But they never do. Considering the many changes constantly taking place in the weight of the submarine, due to leakage through propeller shaft glands, to name one unstoppable source, or water taken in by the evaporators, for instance, it is certain that within a short time the sub’s trim will change. In all cases, the change is in the direction of becoming heavier and, without the intelligent hand of man, she will shortly resume her descent. Nothing, in other words, can float without control between the surface of the sea and the bottom.
Davy Jones might have been perturbed had he observed Triton, the world’s greatest submarine, slither to a halt and commence a series of astonishing gyrations in depth, accompanied by a frenetic blowing and venting of air and grinding of pumps. He would indeed have been justified in suspecting something to have gone seriously wrong. Such was, however, far from the fact. We were well pleased with the results of our drill, which showed that we had more than adequate control of our huge ship, even under the hazardous conditions which result from a complete loss of power; and after a short time, the mock-casualty restored, Triton’s great propellers began to turn purposefully once more and she settled down on her course to the northwest at a speed faster than any submarine had ever traversed these waters.
According to Triton’s Log, it was next day, at about ten-thirty at night, when a calamity of very real proportions confronted us. Intimation of the problem came when Don Fears called me on the ship’s service telephone in my room. For a few days we had had a severe leak around the starboard propeller shaft, which had been growing steadily worse. Now, as Don put it, it was no longer incidental, but of some magnitude. Fears and Curt Shellman were both in the lower level of the engine room, and I got there as soon as possible.
Spotting the leak was easy. Great sheets of water were spurting out around the periphery of the flange and gland through which the propeller shaft passed into the sea, driving a solid white spray perpendicularly outward from the shaft itself around 360° of its circumference, soaking the overhead of the platform deck above, the curved side of the ship outboard of the shaft, and the tiny walk deck. A heavy canvas dropcloth had already been rigged to protect the machinery near the leak, while Curt Shellman and three of his engineers, all of them drenched, were struggling perilously close to the rapidly revolving propeller shaft in their effort to stem the flow of water.
The tremendous racket produced by the hydrantlike force of water striking deck plates and other structures in the engine room made it almost impossible to talk. I put my mouth next to Don Fear’s ear and shouted, “Good Lord, Don, how long has it been this bad?”
Fears looked serious and shouted into my ear in turn. “This is why I called you, Captain. The leak we had before was getting slowly worse and I was thinking of calling you anyway, then suddenly she broke loose.”
“What is the trouble?” I yelled.
Don shook his head. “Don’t know for sure, sir. Curt and his people have been right on it, though. Maybe we’ll have an answer pretty soon.”
“You can’t handle this with the drain pump, Don,” I shouted, enunciating slowly and carefully above the din. “We can’t let these bilges get too full!”
Don nodded understandingly. “We have the drain pump on the line already, Captain, but I think you’re right. The pump won’t be able to keep up with this flood!”
Quite apart from the ultimate safety of the ship herself, if this huge leak could not be stopped, there was a lot of electrical equipment and other delicate machinery in the engine room which would be damaged if the water level rose too high.
“Don,” I said, “we’ll have to stop the starboard shaft. That will help some. At least it will let Curt get closer to the problem. I don’t like him working around the shaft like that while it’s turning.”
Don nodded, shouting in my ear. “Maybe we could come to a shallower depth, too, Captain. That would reduce the pressure and cut down the leak some.”
I assented. It took but a second to dash up the ladder to the upper level, find a telephone, and call the Officer of the Deck. In a moment, the starboard propeller shaft began to slow down, and at the same time the ship angled gently upward. In deference to the amount of water already in the bilges, which would all be concentrated in the after end if too steep an angle were assumed, I had told the Officer of the Deck to bring her up handsomely—that is, slowly and steadily, with good control.
As the outside water pressure was reduced, the leak correspondingly decreased. Shellman cast me a grateful look. I beckoned to him. “Curt,” I said, “we are locking the shaft so that it can’t turn. This will let you get closer to it, at least.”
Shellman was mopping his face with a rag. “Thanks, Captain. I was about to ask if we might do that. I’m afraid to put somebody outboard of the propeller shaft because there’s not much clearance between it and the skin of the ship.”
He did not need to say more. There was perhaps a foot-and-a-half clearance between the propeller shaft and the curve of Triton’s pressure hull or skin. As I watched the propeller shaft
come to a complete stop, there came into view a great bolted coupling by which two sections of the shaft had been joined together. The huge coupling had been rotating previously in a sort of a blur, its machined edges a lethal hazard while the shaft was turning.
With the shaft at a complete halt, Curt and Chief Engine-man Fred Rotgers climbed on top, braving the reduced spray of water, while “Rabbit” Hathaway, a compactly built Engine-man, squirmed under the shaft and into the confined space.
Several minutes later we had the answer. The spit of anger in Rotgers’ voice as he reported the basic cause of the problem was not all due to the salt-water bath he had just experienced. “The _____ nuts on the far side of the gland are so loose you can turn them by hand,” he spluttered.
“How about the locking washers, Chief?” asked Shellman.
“I sure didn’t see any. That’s why they loosened up!” Rotgers glared as he spoke. It was evident that whoever had installed these bolts would have fared badly had the powerful Rotgers been able to get his hands on him at that moment.
“There are locking wires on the inboard side of the gland,” reported Shellman, after a brief inspection.
Further investigation showed that loose bolts were not the end of the trouble. The propeller shaft water seal had been improperly installed, that is, not made tight, either because of the difficulty in reaching some of the bolts or through lack of locking devices. Under the vibration and stress of continual high speed, complication had followed upon complication. Looseness of the bolts on the outboard side had permitted the packing gland to become partially cocked on its seat, and now, tighten the bolts as we would, it remained jammed in a cocked position and could not be straightened. We heaved on the nuts with the biggest wrenches aboard, to the point where Curt feared further pressure might distort or damage the parts even more, but there was no stemming the leak.
Around the World Submerged Page 18