This was done, and a few minutes later the whole party left the submarine, Gif going ahead and the Rovers following the prisoner, each with a pistol ready for use. In this fashion they passed over the gangplank, and then made their way alongside of the underground pond until they came to the spot where the cadets had first discovered the Germans.
“I don’t believe we ought to leave him here,” declared Jack. “That gag might slip and he might have a chance to make considerable noise, and if he did that the others might take the alarm and sail away before we could get help.”
“We made a mistake!” cried Gif. “I thought we were going to injure some of the machinery, so that they couldn’t use the U-boat.”
“You’re right, Gif! I got so excited I forgot all about that,” declared Jack.
“You can run back now and do it if you want to,” said Fred. “I’ll watch the prisoner.”
The young captain and Gif did as had been suggested. On the submarine they looked over the intricate machinery with care, and presently found some things which they could disarrange and which would probably not be noticed immediately. They went to work with vigor, and came away again in less than ten minutes.
“I guess she’s fixed now,” declared Jack to his cousin, when they had rejoined Fred and the prisoner. “If they start up those engines, that submarine will perform stunts they never dreamed of.”
With the flashlight shining ahead and at times on the prisoner, the Rovers and Gif compelled the German to move along the passageway until they gained the opening near the gully.
“Look out there, will you?” cried Gif suddenly, pointing between the bushes to the bay. “There is a big motor boat cruising up and down! Maybe they can give us aid.”
“It looks to me like a revenue boat,” declared Jack, after a hurried inspection. “Say, maybe they are patrolling the bay!”