Aided now by the acquisition of the code book brought from Washington by Bela, they prepared to launch more formidable attacks than heretofore, knowing in advance the disposition of Allied ships, and thus able to choose the most vulnerable point. It was necessary first to ascertain, if possible, whether the code was actually in use as planned. Possibly the book had been missed, and the Yankees had decided to abandon the code for fear it had fallen into enemy hands. To this end all the intercepted radio traffic of the Allies was diligently copied, and every effort made to correlate it with observed movements of Allied forces by sea or air. To the great delight of the Turks, they found messages being sent which conveyed a meaning when decoded in accordance with the system set forth in the book.
Early in January there came a welcome opportunity to verify the code and to satisfy the Turkish Chief of Staff that it was indeed being used by the Allies for directing naval operations. Punta Delgada was heard sending messages which when decoded proved to be addressed to a ship carrying seaplanes headed toward the Portuguese coast. These messages related to a bombing attack on the defenses of Lisbon. Eagerly the Intelligence officers at this port followed the preparations and then the progress of the attack. The seaplane carrier was next heard sending messages to the planes in the air, messages which were readily interpreted by means of the code, and finally, at the time when these dispatches had led them to expect it, the seaplanes appeared, only to be driven off by an overwhelming force of small fighting planes which, thanks to the code, had been prepared in time to prevent a single bombing plane from reaching its objective. The Intelligence officers were greatly elated, and praised the name of Bela.
About a week after this incident, a force of seven submarines set forth from Gibraltar to make a series of destructive attacks on Allied shipping. It was to be a long cruise, and no pains had been spared to equip the submarines with all the munitions they could carry to do their job well, for this was the first time a large group had gone out since the new code had become available to the skippers.
When two days out from Gibraltar, the radio operator on watch in one of the submarines began picking up signals from Allied ships. Word was passed to the others, and all listened intently. The messages were copied and decoded with the key in the stolen book.
The following situation was deciphered: A large and important convoy from Brazil was approaching the danger zone; it had reached its supposed rendezvous and found no escort; no ships responded to its low-powered radio call. Now it was calling Punta Delgada asking for instructions, evidently using just enough power to reach the Naval Headquarters, and incidently the submarines, but endeavoring not to use enough power to be heard in Spain or Portugal. From the exchange of messages it appeared that an earlier dispatch, which should have led to the sending of a destroyer escort, had failed to get through. Owing to this misunderstanding, then, a valuable convoy was already entering the danger zone, and no escort was available for its protection. Punta Delgada was finally heard to instruct the convoy to proceed at maximum speed on a zigzag course and to refrain from using radio; at the moment no destroyers or cruisers were available, but, if possible, an escort would be assembled on the following day and sent to make contact with the convoy farther on.
The submarines were proceeding in a westerly direction, spread out in a long scouting line extending from north to south. With their radio direction-finding apparatus they took bearings on the flagship of the convoy as she sent her messages to Punta Delgada. To their unbounded delight, the position which this indicated corresponded closely with that mentioned by the convoy flagship in her dispatch to Punta Delgada, a point about three hundred miles south of the eastern Azores. Once more the stolen code had proved itself correct.
The intercepted dispatches had revealed what the course of the convoy would be during the next twenty-four hours. So the submarines shaped their own course for the place where they should find their victims the next morning soon after daybreak. Eagerly the officers of the flagship bent to the task of preparing their formation for the attack.
“Bela has served the cause well,” said the Captain; “his reward for this will be great.” And warm was the praise of him echoed in the rejoinders of the others.
As the gray afternoon wore on, the seven long, sinister-looking ships glided steadily westward, their low decks washed by the waves, and only the conning tower of each visible from her next in line. By dawn next day they should be already in the path of the northbound convoy, in plenty of time to re-form on a line stretching east and west which would surely cover the course of their intended victims and thus ensure good prizes for at least one and probably more of the submarines.
As the gray twilight settled down on the sea, the line closed in till not more than three miles separated the ships at the extreme ends. Every valve, every item of machinery and armament was carefully inspected and all necessary tests were made, that no mishap should hinder the reaping of the grim harvest on the morrow. Tense as were the nerves of all, those off duty slept during the night, for a submarine crew must learn the art of sleeping when the chance offers. The captains scarcely slept at all, but, as each new watch went on duty, exhorted the radio operators and hydrophone listeners, going to their posts in the hull, to listen as never before. From ship to ship such messages as occasion required were transmitted by radio phone, with barely enough power to cover the distance intervening between them. Once soon after midnight the seven ships stopped to listen in silence, in case the convoy should be approaching sooner than was expected, but, although lying still in the water increased the range of the hydrophones by many miles, not a sound was heard.