The warlike character of their ships was even more cleverly hidden. In the early days the guns were placed behind the bulwarks, which, when a lever was pulled, would fall down, thus giving them an unobstructed range at the submarine. In order to make the sides of the ships collapsible, certain seams were unavoidably left in the plates, where the detachable part joined the main structure. The U-boat commanders soon learned to look for these betraying seams before coming to the surface. They would sail submerged around the ship, the periscope minutely examining the sides, much as a scientist examines his specimens with a microscope. This practice made it necessary to conceal the guns more carefully. The places which were most serviceable for this purpose were the hatchways—those huge wells, extending from the deck to the bottom, which are used for loading and unloading cargo. Platforms were erected in these openings, and on these guns were emplaced; a covering of tarpaulin completely hid them; yet a lever, pulled by the gun crews, would cause the sides of the hatchway covers to fall instantaneously. Other guns were placed under lifeboats, which, by a similar mechanism, would fall apart, or rise in the air, exposing the gun. Perhaps the most deceptive device of all was a gun placed upon the stern, and, with its crew, constantly exposed to public gaze. Since most merchantmen carried such a gun, its absence on a mystery ship would in itself have caused suspicion; this armament not only helped the disguise, but served a useful purpose in luring the submarine. At the first glimpse of a U-boat on the surface, usually several miles away, the gun crew would begin shooting; but they always took care that the shots fell short, thus convincing the submarine that it had the advantage of range and so inducing it to close.
Captain Campbell and his associates paid as much attention to details in their ships as in their personal appearance. The ship's wash did not expose the flannels that are affected by naval men but the dungarees that are popular with merchant sailors. Sometimes a side of beef would be hung out in plain view; this not only kept up the fiction that the ship was an innocent tramp, but it served as a tempting bait to the not too well-fed crew of the submarine. Particularly tempting cargoes were occasionally put on deck. One of the ships carried several papier-mâché freight cars of the small European type covered with legends which indicated that they were loaded with ammunition and bound for Mesopotamia. It is easy to imagine how eagerly the Hun would wish to sink that cargo!
These ships were so effectively disguised that even the most experienced eyes could not discover their real character. For weeks they could lie in dock, the dockmen never suspecting that they were armed to the teeth. Even the pilots who went aboard to take them into harbour never discovered that they were not the merchant ships which they pretended to be. Captain Hanrahan, who commanded the U.S. mystery ship Santee, based on Queenstown, once entertained on board an Irishman from Cork. The conversation which took place between this American naval officer—who, in his disguise, was indistinguishable from a tramp skipper of many years' experience—disclosed the complete ignorance of the guest concerning the true character of the boat.
"How do you like these Americans?" Captain Hanrahan innocently asked.
"They are eating us out of house and home!" the indignant Irishman remarked. The information was a little inaccurate, since all our food supplies were brought from the United States; but the remark was reassuring as proving that the ship's disguise had not been penetrated. Such precautions were the more necessary in a port like Queenstown where our forces were surrounded by spies who were in constant communication with the enemy.
I can personally testify to the difficulty of identifying a mystery ship. One day Admiral Bayly suggested that we should go out in the harbour and visit one of these vessels lying there preparatory to sailing on a cruise. Several merchantmen were at anchor in port. We steamed close around one in the Admiral's barge and examined her very carefully through our glasses from a short distance. Concluding that this was not the vessel we were seeking, we went to another merchantman. This did not show any signs of being a mystery ship; we therefore hailed the skipper, who told us the one which we had first visited was the mystery ship. We went back, boarded her, and began examining her appliances. The crew was dressed in the ordinary sloppy clothes of a merchantman's deck-hands; the officers wore the usual merchant ship uniform, and everything was as unmilitary as a merchant ship usually is. The vessel had quite a long deckhouse built of light steel. The captain told us that two guns were concealed in this structure; he suggested that we should walk all around it and see if we could point out from a close inspection the location of the guns. We searched carefully, but were utterly unable to discover where the guns were. The captain then sent the crew to quarters and told us to stand clear. At the word of command one of the plates of the perpendicular side of the deckhouse slid out of the way as quickly as a flash. The rail at the ship's side in front of the gun fell down and a boat davit swung out of the way. At the same time the gun crew swung the gun out and fired a primer to indicate how quickly they could have fired a real shot. The captain also showed us a boat upside down on the deckhouse—merchantmen frequently carry one boat in this position. At a word a lever was pulled down below and the boat reared up in the air and revealed underneath a gun and its crew. On the poop was a large crate about 6 x 6 x 8 or 10 feet. At a touch of the lever the sides of this crate fell down and revealed another gun.
For the greater part of 1917 from twenty to thirty of these ships sailed back and forth in the Atlantic, always choosing those parts of the seas where they were most likely to meet submarines. They were "merchantmen" of all kinds—tramp steamers, coasting vessels, trawlers, and schooners. Perhaps the most distressing part of existence on one of these ships was its monotony: day would follow day; week would follow week; and sometimes months would pass without encountering a single submarine. Captain Campbell himself spent nine months on his first mystery ship before even sighting an enemy, and many of his successors had a similar experience. The mystery boat was a patient fisherman, constantly expecting a bite and frequently going for long periods without the slightest nibble. This kind of an existence was not only disappointing but also exceedingly nerve racking; all during this waiting period the officers and men had to keep themselves constantly at attention; the vaudeville show which they were maintaining for the benefit of a possible periscope had to go on continuously; a moment's forgetfulness or relaxation might betray their secret, and make their experiment a failure. The fearful tediousness of this kind of life had a more nerve-racking effect upon the officers and men than the most exciting battles, and practically all the mystery ship men who broke down fell victims not to the dangers of their enterprise, but to this dreadful tension of sailing for weeks and months without coming to close quarters with their enemy.
About the most welcome sight to a mystery ship, after a period of inactivity, was the wake of a torpedo speeding in its direction. Nothing could possibly disappoint it more than to see this torpedo pass astern or forward without hitting the vessel. In such a contingency the genuine merchant ship would make every possible effort to turn out of the torpedo's way: the helmsman of the mystery ship, however, would take all possible precautions to see that his vessel was hit. This, however, he had to do with the utmost cleverness, else the fact that he was attempting to collide with several hundred pounds of gun-cotton would in itself betray him to the submarine. Not improbably several members of the crew might be killed when the torpedo struck, but that was all part of the game which they were playing. More important than the lives of the men was the fate of the ship; if this could remain afloat long enough to give the gunners a good chance at the submarine, everybody on board would be satisfied. There was, however, little danger that the mystery ship would go down immediately; for all available cargo space had been filled with wood, which gave the vessel sufficient buoyancy sometimes to survive many torpedoes.
Of course this, as well as all the other details of the vessel, was unknown to the skipper of the submerged submarine. Having struck his victim in a vital spot, he had every reason to believe that it would disappear beneath the waves within a reasonable period. The business of the disguised merchantman was to encourage this delusion in every possible way. From the time that the torpedo struck, the mystery ship behaved precisely as the every-day cargo carrier, caught in a similar predicament, would have done. A carefully drilled contingent of the crew, known as the "panic party," enacted the rôle of the men on a torpedoed vessel. They ran to and fro on the deck, apparently in a state of high consternation, now rushing below and emerging with some personal treasure, perhaps an old suit of clothes tucked under the arm, perhaps the ship's cat or parrot, or a small handbag hastily stuffed with odds and ends. Under the control of the navigating officer these men would make for a lifeboat, which they would lower in realistic fashion—sometimes going so far, in their stage play, as to upset it, leaving the men puffing and scrambling in the water. One member of the crew, usually the navigator, dressed up as the "captain," did his best to supervise these operations. Finally, after everybody had left, and the vessel was settling at bow or stern, the "captain" would come to the side, cast one final glance at his sinking ship, drop a roll of papers into a lifeboat—ostensibly the precious documents which were so coveted by the submarine as an evidence of success—lower himself with one or two companions, and row in the direction of the other lifeboats. Properly placing these lifeboats, after "abandoning ship," was itself one of the finest points in the plot. If the submarine rose to the surface it would invariably steer first for those little boats, looking for prisoners or the ship's papers; the boats' crews, therefore, had instructions to take up a station on a bearing from which the ship's guns could most successfully rake the submarine. That this manœuvre involved great danger to the men in the lifeboats was a matter of no consideration in the desperate enterprise in which they were engaged.