This latter event proved to be the safe arrival of a convoyed naval collier, the Jupiter, which served as a harbinger of the fleet of transports conveying the American troops. It carried a cargo of army provisions, including over 10,000 tons of wheat.
The arrival of the first division of transports at an unnamed French seaport was reported on June 26, 1917. They were signaled from the deserted quays of the town at 6 o'clock in the morning, and as they steamed toward port in a long line, according to an eloquent eyewitness, they appeared a "veritable armada," whose black hulls showed clearly against the horizon, while the gray outlines of their escorting destroyers were almost blotted out in the lead-colored sea. Dominating all was an enormous American cruiser with its peculiar upper basket works. The warships went to their allotted moorings with clockwork precision, while tugs took charge of the transports and towed them to their berths. Resounding cheers were exchanged between the troops which lined the rails of the incoming ships and the populace which lined the quays.
The next day came a formal intimation from Paris that the first expeditionary unit of American troops, in command of Major General William L. Sibert, had safely reached their destination. Rear Admiral Gleaves, commanding the destroyer force which accompanied the transports, telegraphed the Navy Department to the same effect. But it subsequently transpired that all had not been plain sailing in passing through the submarine zone.
The expedition was divided into contingents, each contingent including troopships and a naval escort designed to hold off any German raiders that might be sighted. An ocean rendezvous had also been arranged with the American destroyer flotilla under Admiral Sims, which had been operating in European waters since May 4, 1917, in order that the passage of the danger zone might be attended by every possible protection. Frequent indications pointing to the presence of submarines in the expedition's course were observed as the transports neared European waters. The passage through the infested zone was therefore made at high speed; the men were prepared for any emergency; boats and life belts were at hand for instant use; and watches at every lookout were heavily reenforced.
These precautions were timely and more than warranted. The first contingent of transports was attacked twice by German U-boats. Admiral Gleaves, describing these incidents in reporting to Admiral Mayo, commander in chief of the Atlantic fleet, said the first attack was made at 10.15 p. m. on June 22. The location, formation, and names of the transports and the convoys, the speed they made, and the method of proceeding, were suppressed in the account made public by the Navy Department.
It appeared that the destroyers' flagship, which led the transport fleet, was the first to encounter the submarine. At least the officer on deck and others on the bridge saw a white streak about fifty yards ahead of the ship, crossing from starboard to port at right angles to the ship's course. The ship was sharply turned 90 degrees to starboard at high speed, a general alarm was sounded, and torpedo crews were ordered to their guns. One of the destroyers called A and one of the transports astern opened fire, the destroyer's shell being fitted with tracers. Other members of the convoying destroyers turned to the right and left. At first it was thought on board the flagship that the white streak was caused by a torpedo, but later reports from other ships warranted the conclusion that it was the wake of the submarine itself. At 10.25 the wake of a torpedo was sighted directly across the bow of the destroyer called A, about thirty yards ahead. The ship's course was swung to the left, and shots were fired from port batteries in alarm, accompanied by blasts from the siren. The destroyer then passed through a wake believed to be from the passing submarine. A second torpedo passed under the destroyer A's stern ten minutes later.
Another destroyer known as D was also the target of a torpedo which passed it from starboard to port across the bow about forty yards ahead of the ship, leaving a perceptible wake visible for about four or five hundred yards.
The submarine sighted by the flagship immediately engaged the attention of destroyer B. In fact it darted under the latter and passed the flagship's bows, disappearing close aboard on the flagship's port bow between the destroyer columns. The B followed the wake between the columns and reported strong indications of two submarines astern, which grew fainter. The B afterward guarded the rear of the convoy.
So much for the ghostly movements of the submarine or submarines which crossed the tracks of the first contingent of American transports on the night of June 22. In the absence of more tangible proof of their presence beyond that provided by white streaks and wakes on the sea surface, the incident might well have been a false alarm. It only occasioned much excitement and activity. But its interest lay in the alertness of the destroyers to danger. The officers on board the flotilla had no doubt at all that the danger was real. Admiral Gleaves, indeed, saw circumstantial evidence of the menace in alluding to a bulletin of the French General Staff which referred to the activities of a German submarine off the Azores. This U-boat, the bulletin said, was ordered to watch in the vicinity of those islands, "at such a distance as it was supposed the enemy American convoy would pass from the Azores."
The second contingent of transports, which arrived in France a week later, had a similar experience, with the important difference that their encounters with submarines took place in broad daylight, and that the firing at one of them produced material traces of the enemy's proximity. Two submarines were met on the morning of June 26, 1917, one at 11.30, when the ships were about a hundred miles off the coast of France, the other an hour later. The destroyer H, which was leading, sighted the first U-boat, and the I pursued the wake, but without making any further discovery. The second episode was more convincing of the actual presence of a submarine. The destroyer J saw the bow wave of one at a distance of 1,500 yards and headed for it at a rapid speed. The pointers at the destroyer's gun sighted its periscope several times for several seconds; but it disappeared each time before they could get their aim, which the zigzagging of the ship impeded. Presently the J passed about twenty-five yards ahead of a mass of bubbles which obviously came from the submarine's wake. A deep charge was fired just ahead of these bubbles. Several pieces of timber, quantities of oil and débris then came to the surface. Nothing more was seen of the submarine. There was plain evidence that it had been sunk.