Another ruse adopted was that of changing the disguise of a decoy ship during the night, so that she could not be identified by a submarine which had previously made an attack upon her. In all cases of disguise or of changing disguise it was essential that the decoy ship should assume the identity of some class of vessel likely to be met with in the particular area in which she was working, and obviously the courses steered were chosen with that object in view.
Again, since for success it was essential to induce the submarine to come within close range so that the decoy ship's gunfire should be immediately effective, it was necessary that her disguise should stand the closest possible examination through the periscope of a submarine. German submarine commanders, after a short experience of decoy ships, were most careful not to bring their vessels to the surface in proximity to craft that were apparently merchant ships until they had subjected them to the sharpest scrutiny at short range through the periscope, and the usual practice of an experienced submarine commander was to steer round the ship, keeping submerged all the time.
Not only was it essential that there should be no sign of an armament in the decoy ship, or a man-of-war-like appearance in any respect, but when the "panic" signal was made to lead the submarine commander to think that his attack had succeeded, precautions had to be taken against the presence of more than the ordinary number of men in the boats lowered and sent away with the supposed whole ship's company; also the sight of any men left on board would at once betray the real character of the decoy ship and result in the disappearance of the submarine and the probable sinking of the disguised craft by torpedo fire.
During the late summer of 1917 it became evident that the submarine commanders had become so suspicious of decoy craft that the chances of success by the larger cargo vessels were not sufficient to justify any further addition to existing numbers in view of the increasing shortage of shipping; a considerable fleet of steamers building for this purpose was therefore diverted to trade purposes. The number of smaller vessels, particularly sailing craft, was, however, increased especially in Mediterranean waters where they had not been previously operating on an extensive scale.
It is impossible to close these remarks on this class of vessel without testifying once more to the splendid gallantry, self-sacrifice, skilful resource and magnificent discipline shown by those on board. This is illustrated by descriptions of a few typical actions fought during 1917.
The first which I relate took place on February 17, 1917, when a decoy vessel, a steamship armed with five 12-pounder guns, commanded by that most gallant officer, Captain Gordon Campbell, R.N., was torpedoed by a submarine in a position Lat. 51.34 N., Long. 11.23 W.
Captain Campbell saw the torpedo coming and manoeuvred to try and avoid being hit in the engine-room, but as he purposely always selected a very slow ship for decoy work his attempt was only partially successful and the engine-room began to fill. No signal for assistance was made, however, as Captain Campbell feared that such a signal might bring another vessel on the scene and this would naturally scare the submarine away. The usual procedure of abandoning the ship in the boats with every appearance of haste was carried out, only sufficient hands remaining hidden on board to work the guns. The periscope of the submarine was next sighted on the quarter within 200 or 300 yards, and she came slowly past the ship still submerged and evidently examining the vessel closely through the periscope. She passed within a few yards of the ship, then crossed the bow and came to the surface about 200 yards off and passed down the port side again close to. Captain Campbell waited until every gun would bear before giving the signal for "action." The decoy ship's true character was then revealed; concealed gunports were thrown open; colours were hoisted, and a hot fire opened from all guns. The submarine was hit at once and continued to be hit so rapidly that it was evidently impossible for her to submerge. She sank in a very short time. One officer and one man were picked up. A signal was then made for assistance and help arrived within a couple of hours. The decoy ship was rapidly filling, but efforts were made to tow her into port, and with the greatest difficulty, and entirely owing to the splendid manner in which all hands stuck to the work, she was brought into Berehaven with her stern under water thirty-six hours later and beached. The great restraint shown by Captain Campbell, in withholding fire as the submarine passed her in a submerged condition, and the truly wonderful discipline and steadiness and ingenuity which baffled so close an examination of the ship were the outstanding features of this great exploit.
On April 22, 1917, a decoy ship known as "Q22," a small sailing vessel with auxiliary power, armed with two 12-pounder guns, and commanded by Lieutenant Irvine, R.N.R., while in a position about fifty miles south of Kinsale Head, sighted a submarine on the surface which opened fire immediately at a range of about 4,000 yards. The fire was accurate and the decoy ship was hit frequently, two men being killed and four wounded in a few minutes and the vessel considerably damaged. As further concealment appeared useless the guns were then unmasked and the fire returned with apparently good results, several hits being claimed. The enemy's fire then fell off in accuracy and she increased the range, and after about one and a half hours' fighting the light became too bad to continue the action. It was thought that the submarine was sunk, but there was no positive evidence of sinking.
On April 30, 1917, a decoy ship—H.M.S. Prize—a small schooner with auxiliary power, armed with two 12-pounder guns and commanded by Lieutenant W.E. Sanders, R.N.R., a New Zealand officer, sighted, when in position Lat. 49.44 N., Long. 11.42 W., a submarine about two miles away on the port beam at 8.30 P.M. At 8.45 P.M. the submarine opened fire on the Prize and the "abandon ship" party left in a small boat. The submarine gradually approached, continuing to pour in a heavy fire and making two hits on the Prize which put the motor out of action, wrecked the wireless office, and caused much internal damage besides letting a great deal of water into the ship.
The crew of the Prize remained quietly hidden at their concealed guns throughout this punishment, which continued for forty minutes as the submarine closed, coming up from right astern, a position no doubt which she considered one of safety. When close to she sheered off and passed to the port beam at a distance of about one hundred yards. At this moment Lieutenant Sanders gave the order for "action." The guns were exposed and a devastating fire opened at point blank range, but not before the submarine had fired both her guns, obtaining two more hits, and wounding several of the crew of the Prize. The first shell fired from the Prize hit the foremost gun of the submarine and blew it overboard, and a later shot knocked away the conning tower. The submarine went ahead and the Prize tried to follow, but the damage to her motor prevented much movement. The firing continued as the submarine moved away, and after an interval she appeared to be on fire and to sink. This occurred shortly after 9.0 P.M., when it was nearly dark. The Prize sent her boats to pick up survivors, three being taken out of the water, including the commander and one other officer. The prisoners on coming on board expressed their willingness to assist in taking the Prize into port. It did not at this time seem likely that she would long remain afloat, but by great exertion and good seamanship the leaks were got under to a sufficient extent to allow of the ship being kept afloat by pumping. The prisoners gave considerable help, especially when the ship caught fire whilst starting the motor again. On May 2 she met a motor launch off the coast of Ireland and was towed into port. In spite of the undoubted great damage to the submarine, damage confirmed by the survivors, who were apparently blown overboard with the conning tower, and who had no thought other than that she had been sunk, later intelligence showed that she succeeded in reaching Germany in a very disabled condition. This incident accentuated still further the recurrent difficulty of making definite statements as to the fate of enemy submarines, for the evidence in this case seemed absolutely conclusive. The commander of the submarine was so impressed with the conduct of the crew of the Prize that when examined subsequently in London he stated that he did not consider it any disgrace to have been beaten by her, as he could not have believed it possible for any ship's company belonging to any nation in the world to have been imbued with such discipline as to stand the shelling to which he subjected the Prize without any sign being made which would give away her true character.