The following submarines, with all or part of their crews, have been accidentally lost in time of peace:

The A-1 was engaged in manoeuvers off Spithead, England, when she rose to the surface right under the bows of the fast-steaming Union Castle Liner Berwick Castle. Before anything could be done, the sharp prow of the steamer had cut a great gash in the thin hull of the submarine and sent her to the bottom with all her crew. This was in broad daylight; her sister-ship C-11 was rammed and sunk by another liner three years later, at night. The PluviÔse of the French navy escaped the bow of an on-coming cross-channel steamer when the submarine came up at the entrance to Calais Harbor, only to have her topsides crushed in by a blow from one of the paddle-wheels. Collisions like these are less likely to happen nowadays, for the navigating officer of a modern submarine can take a look round the horizon through the periscope from a depth sufficient to let most steamers pass harmlessly over him, and in case of darkness or fog, he can detect the vibrations of approaching propellers by means of the Fessenden oscillator or some similar device. Yet the frequency with which submarines have been intentionally rammed and sunk in the present war shows that they would still be liable to rise blindly to their destruction in time of peace.

The vapor from a leaking fuel-tank, making an explosive mixture with the air inside the submarine and set off by a spark from the electrical machinery, has caused many accidents of another kind. Such an explosion took place on the original Holland, shortly after she was taken into the government service, but fortunately without killing any one. As the crew of the British A-5 were filling the fuel tanks of their vessel with gasoline, some of them were blown up through the open hatchway and into the sea by a burst of flaming vapor that killed six men and terribly injured twelve more. A rescue party that entered the boat to save the men still left aboard had several of its own members disabled by a second explosion. The vessel itself, however, was almost unharmed. But not long afterwards, another submarine of the same ill-fated class, the A-8, was lying off Plymouth breakwater with her hatches open, when the people on shore heard three distinct explosions on board her and saw her suddenly submerge. Her crew evidently got the hatches closed before she went down, as they sent up signals that they were alive but unable to rise. Two hours later a fourth explosion took place and all hope was abandoned.

This danger has been guarded against by better construction of tanks and valves, and very greatly lessened by the substitution of the heavy oil used in the Diesel engines for the more costly and volatile gasoline.

Besides igniting explosive oil vapors with their sparks, the old-fashioned sulphuric acid and lead storage batteries still used in many submarines are a great source of danger in themselves. The jars are too easily broken, and the leaking acid eats into the steel plating of the boat, weakening it if not actually letting in the sea water. And if salt water comes in contact with a battery of this type, then chlorin gas—the same poisonous gas that the Germans use against the Allies’ trenches—is generated and the crew are in very great danger of suffocation. The new Edison alkali storage battery, besides being lighter and more durable, uses no acid and cannot give off chlorin when saturated with sea water.

The remaining great danger is that a submarine may get out of control and submerge too quickly, so that it either strikes the bottom, at the risk of being crushed in or entangled, or descends to so great a depth that its sides are forced in by the pressure of the water outside, which also prevents the submarine from discharging the water in its ballast tanks and escaping to the surface. Detachable safety weights and keels to lighten the boat in such an emergency date back to the time of Bushnell and J. Day. A more modern device is to have a hydrostatic valve (see page 51) set to correspond with the pressure of a certain depth of water, so that if the submarine goes below this the valve will be forced in and automatically “blow the tanks.”

A submarine that sank too deep was the No. 6, of the Imperial Japanese navy, which disappeared while manoeuvering in Hiroshima Bay, on April 15, 1910. When she was found, her entire crew lay dead at their stations, and in the conning-tower, beside the body of the commander, was the following letter written by that officer, Lieutenant Takuma Faotomu:

“Although there is indeed no excuse to make for the sinking of his Imperial Majesty’s boat, and for the doing away of subordinates through my heedlessness, all on board the boat have discharged their duties well and in everything acted calmly until death. Although we are dying in the pursuance of our duty to the State, the only regret we have is due to anxiety lest the men of the world misunderstand the matter, and that thereby a blow may be given to the future development of the submarine.

“Gentlemen, we hope you will be increasingly diligent and not fail to appreciate the cause of the accident, and that you will devote your entire energy to investigate everything and so secure the future development of submarines. If this be done we have nothing to regret.

“While going through gasoline submerged exercises we submerged too far, and when we attempted to shut the sluice-valve, the chain broke. “Then we tried to close the sluice-valve by hand, but it was too late, for the afterpart was full of water, and the boat sank at an angle of about twenty-five degrees. The boat came to rest at an incline of about twelve degrees, pointing towards the stern. The switchboard being under water the electric lights went out. Offensive gas developed and breathing became difficult. The boat sank about 10 A.M. on the 15th, and though suffering at the time from this offensive gas, we endeavored to expel the water by hand pumps. As the vessel went down we expelled the water from the main tank. As the light has gone out the gage cannot be seen, but we know the water has been expelled from the main tank.

“We cannot use the electric current at all. The battery is leaking but no salt water has reached it and chlorin gas has not developed. We only rely on the hand pump now.

“The above was written under the light of the conning-tower, at about 11.45 o’clock. We are now soaked by the water that has made its way in. Our clothes are wet and we feel cold. I had been accustomed to warn my shipmates that their behavior (in an emergency) should be calm and deliberate, as well as brave, yet not too deliberate, lest work be retarded. People may be tempted to ridicule this after this failure, but I am perfectly confident that my words have not been mistaken.

“The depth gage of the conning-tower indicates 52 feet, and despite our efforts to expel the water the pump stopped and would not work after 12 o’clock. The depth in this neighborhood being ten fathoms, the reading may be correct. “The officers and men of submarines should be chosen from the bravest of the brave or there will be annoyances in cases like this. Happily all the members of this crew have discharged their duties well and I am satisfied. I have always expected death whenever I left my home, and therefore my will is already in the drawer at Karasaki. (This remark applies only to my private affairs and is really superfluous. Messrs. Taguchi and Asami will please inform my father of this.)

“I respectfully request that none of the families left by my subordinates suffer. The only thing I am anxious about is this.

“Atmospheric pressure is increasing and I feel as if my tympanum were breaking.

“12.30 o’clock. Respiration is extraordinarily difficult. I mean I am breathing gasoline. I am intoxicated with gasoline.

“It is 12.40 o’clock.”

Those were the last words written by Lieutenant Takuma Faotomu, bravest of the brave.

Very many ingenious devices have been invented to enable the crew of a stranded submarine to escape. The best-known and most widely used is some form of the air-lock or diver’s chamber, as described in the chapter on the Lake boats. Through this the crew can pass in succession to the water outside and swim to the surface. If the depth is so great that an unprotected swimmer would be crushed by the weight of water above him, there is a great variety of safety-helmets, and of jackets with mouth-pieces leading to tanks containing enough air under moderate pressure to inflate the lungs and cheeks so that the internal pressure of the body will counteract that of the water. An escaping seaman, burdened with such a device, cannot rise unaided to the surface but must climb or be hauled up by a rope let down from above. Moreover, he must not ascend too rapidly, or the pressure within his body will dangerously exceed that without, as if he had been suddenly picked up at the seashore and carried to the top of the Andes. The human body is too delicate and elaborate a structure to be carelessly turned into a compressed-air tank. The surplus oxygen forms bubbles which try to force their way out through the tissues of the body, causing intense pain, and possibly paralysis or death. To avoid this, divers are brought up from any great depth by slow and careful stages, unless they can be placed at once in specially-constructed tanks on shore, where the pressure they are under can be gradually reduced to normal.

A covered lifeboat carried in a socket on the submarine’s deck, so that in case of accidental stranding the crew could get into the small boat from below, close the hatch cover, release the lifeboat from within, and rise safely and comfortably to the surface, was an attractive feature of the Plongeur in 1863, and of many projected but unbuilt submarines since then. A detachable conning-tower, containing a small lifeboat that could be launched after the safety compartment had risen to the surface, has also been designed and patented more than once. Theoretically, these devices seem admirable but naval architects will have none of them. The reason for this is very simple. A submarine is primarily a warship, an instrument of destruction, and its carrying capacity is too limited to permit several hundredweight of torpedoes or supplies being crowded out by a lifeboat or a score of safety-helmets. A divers’ compartment and one or two ordinary diving-suits—for these things are of military value—and a buoy that can be sent up to mark the spot where the boat has gone down are as much as you can expect to find in the average naval submarine.

One of the most instructive accidents that ever happened to an undersea boat was the loss and rescue of the German U-3. She sank to the bottom of Kiel Harbor on January 17, 1911. A small spherical buoy was released and rose to the surface, where it was picked up and a telephone attached to the end of the thin wire cable.

“Hello!”

“Hello! This is the captain of the U-3 speaking. We cannot rise, but we are resting easy and have air enough to last forty-eight hours.”

“Good. The steam salvage-dock Vulcan has been sent for and will be here before then, Herr Kapitan.”

But before the Vulcan arrived, it occurred to some one in authority to attempt to raise the U-3 with a large floating crane then available. The strong steel chain ready coiled at the lower end of the buoy-line was drawn up and made fast to the crane, which could not lift the 300-ton submarine bodily, but succeeded in hauling up its bow sufficiently for the twenty-seven petty officers and seamen on board the U-3 to be shot up through the torpedo tube to the surface. The captain and his two lieutenants chose to remain. Shortly afterwards the chain slipped and broke off one of the boat’s ventilators, letting water into the hull and drowning all three officers.

Then the sea-going, steam salvage-dock Vulcan reached the scene and brought the U-3 to the surface in three hours.

“The Vulcan is a double-hulled vessel, 230 feet in length with a lifting capacity of 500 tons. The width between the two hulls is sufficient to admit with good clearance the largest submarines. At a suitable height a shelf is formed along each wall of the interior opening, and upon this rests the removable floor of the dock. The two hulls of the ship are each built with water-tight compartments of large capacity, similar to those which are found in the side walls of the ordinary floating dock. When a sunken submarine is to be raised, the Vulcan steams to the wreck and is moored securely in position above it. Spanning the well between the two hulls are two massive gantry cranes, each provided with heavy lifting tackle driven by electric motors. The first operation is to fill the compartments until the vessel has sunk to the required depth. The floor of the dock is then moved clear of the well. The lifting tackles are now lowered and made fast, either to chains which have been slung around the body of the submarine, or to two massive eyebolts which are permanently riveted into the submarine’s hull. At the order to hoist away, the submarine is lifted free from the mud and drawn up within the well, until its bottom is clear of the supporting shelves on the inner faces of the two hulls, above referred to. The dock floor is then placed in position on the shelves, the water is pumped out of the two hulls, and the Vulcan rises, lifting the submarine and the dock floor clear of the water.”18

A similar vessel was built by the French government as a result of public indignation over the delay in raising the sunken PluviÔse. Great Britain has a salvage dock with a lifting capacity of 1000 tons. But the most remarkable craft of this kind belongs to Italy and was designed by the famous engineer Major Cesare Laurenti, technical director of the Fiat-San Giorgio works, builders of some of the world’s best submarines. She is a twin-hulled vessel, fitted not only to pick a sunken submarine from the sea bottom, but to care for it in every way, for she is also a floating dry-dock, capable of repairing two of the largest submarines, besides being a fully equipped mother-ship for a flotilla of six. With the ends of her central tunnel closed by a false stem and stern, and propelled by twin screws driven by powerful Diesel engines, she is a fast and seaworthy vessel, capable of keeping company with her flotilla on a surface cruise. She carries a sufficient armament of quick-firing guns to beat off a hostile destroyer. But the most noteworthy feature of the Laurenti dock is a long steel cylinder, capable of enduring great pressure from within, that is used to test the resisting strength of new submarines. A new boat, or a section of a proposed new type, is placed in this tube, which is filled with water that is then compressed by pumps, reproducing the effect of submergence to any desired depth.

The United States navy tests each new submarine built for it by actually lowering the boat, with no one in it, to a depth of 200 feet. We have no Laurenti dock, no Vulcan, no sea-going salvage dock of any kind. The tender Fulton has a powerful crane, but she cannot be on the Atlantic and Pacific coasts and in the Far East, simultaneously.

“The difficulties encountered in raising the sunken British submarine A-3,” wrote Mr. R.G. Skerrett in the “Scientific American” some years ago, “have in them a note of warning for us. We are steadily adding to our flotilla of under-water boats, and yet we have no proper facilities in the government service for the prompt salvage of any of these boats should they be carried suddenly to the bottom. We have been fortunate so far in escaping serious accidents, but that is no reason for assuming that we are any more likely to be immune from disaster than any other naval service. We should profit by the catastrophes which have befallen England, Russia, France, Germany, and Japan, and no longer continue unprepared for kindred mishaps.”19

We refused to profit and we continued unprepared. Then came a brief official cablegram from Hawaii, “Honolulu, March 25, 1915. U.S. submarine F-4 left tender at 9 A.M. for submerged run. Failed to return to surface.”

The other two submarines on the station and motor-boats from the tender Alert cruised about till they found the spot where oil and air-bubbles were coming to the surface. Two tugs then swept the bottom with a two-thousand foot sweep of chains and wire cables, which caught early the next morning on what proved to be the lost submarine, in three hundred feet of water, about a mile and a half outside the entrance to Honolulu Harbor.

For twenty-four hours or so the navy department held out the hope that the men on board her were still alive and might be rescued. But there was nothing ready to rescue them with. Three weeks were spent in building the windlasses for an improvised salvage-dock made out of two mud scows. In the meanwhile, a detachment of the department’s most skilled divers were sent out from the Brooklyn Navy Yard. With their aid, strong wire cables were passed under the submarine’s hull. While engaged on this work, one of the divers, Chief Gunner’s Mate Frank Crilley, broke all deep submergence records by descending to a depth of 288 feet. As a result, his lungs were severely injured and he soon afterwards developed pneumonia.

The wire ropes chafed through and were replaced by chains. Then the F-4 was lifted from the bottom and towed inshore to a depth of fifty feet. Here a heavy storm set in and the lines had to be cast off. Six big cylindrical-shaped pontoons were then built at San Francisco and brought out to Honolulu on the cruiser Maryland. Divers passed fresh chains under the F-4, the pontoons were sunk on either side of her, and coupled together. Then the water was blown out of the pontoons by compressed-air piped down from above, the F-4 was raised to the surface, and towed into dry dock.

No decipherable written record was discovered inside her hull, which was filled with sand washed in through a large hole made in the plating by the chafing of the chains. But the story of the disaster was written in the plates and rivets of the vessel herself, and skilfully deduced and reconstructed by a board of inquiry, headed by Rear-Admiral Boush. Their report, which was not made public till October 27, told dramatically how the corroded condition of the lead lining in the battery tanks had let the acid eat away the rivets in the port wall of the forward tank. Salt water thus entered part of the battery, producing chlorin gas, which exploded violently, admitting more water, till the submarine began to sink by the head, in spite of the raising of her diving-rudders.

“Automatic blow was tripped, and blow valve on auxiliary tank opened in the endeavor to check downward momentum. Manoeuvering with propellers probably took place. The appreciable length of time requisite for air to build up in ballast tanks for the expulsion of sufficient quantities of water resulted in the vessel reaching crushing depth.

“Seams of the vessel began to open, and probably through open torpedo tubes and seams water entered the vessel and a condition of positive buoyancy was never attained.

“There followed actual disaster. The vessel began filling with water. The personnel abandoned stations and many sought refuge in the engine room, closing the door. Under great pressure the engine room bulkhead failed suddenly, leaving the vessel on the bottom, completely flooded.”

All the boats of the “F” class had already been withdrawn from the service, by order of Secretary Daniels. Their place at Honolulu was taken by four boats of the “K” class, which made the 2100 mile voyage out from San Francisco under their own power.