"I wonder if that boat can be in the service of those who are annoying us?" Tom muttered. "It's an even chance that it is a 'hostile ship,'" Prescott suggested. "You have a motor boat here. I'm inclined to think you ought to use it in overhauling that suspicious craft. Of course you'd have no right unless there was a police officer along. Can you get one?" "The authorities in Blixton would send a policeman on request." "Then send a messenger to request them to send over a policeman in citizen's clothes," proposed Dick. Tom promptly despatched Foreman Dill on that errand. "Now don't let the men on the boat see that you're paying any more attention," Prescott advised. "Leave it to me, and I'll contrive to keep the boat and its people under observation without looking too plainly in their direction." In due time the plain clothes policeman arrived. He, the young engineers and the army lieutenant boarded the "Morton," which put out from the landing as though on a trip of inspection of the wall. "Don't anyone look over at the sloop," Prescott urged. "I'll do the watching. A fellow on that craft is holding the glasses on us right now. Officer, do you demand the assistance of all present in any police duty that may come up?" "I do," replied the Blixton policeman, a man named Carnes, returning Prescott's wink. "All right, then," laughed Dick. "That demand makes policemen of us all. Tom, you can turn, now, when ready, and put on full speed in going after that craft." Reade gave the order for full speed, then took the steering wheel himself. "Guilty conscience!" laughed Prescott. "There's the sloop putting about at once and heading away from us." "They can't get away from us, in this light wind," chuckled the young chief engineer. A few minutes later the "Morton" came up within easy hailing distance of the sloop, aboard which only one man now appeared. "Sloop ahoy!" called the policeman. "What are you doing in these waters?" "Looking for a good fishing ground," answered the dark-faced man at the tiller. "Then you're too far in by some three miles," answered the policeman. "Thank you, cap'n," acknowledged the sailing master of the sloop. "You're welcome," the policeman continued, "but ease off your sheet and lay to. We want to come aboard." "You can't!" flatly retorted the skipper. "You're wrong there," retorted the policeman. "This is a police party, and I tell you that we are coming aboard. Lay to, or we shall have to start a lot of trouble for you." In the policeman's hand suddenly glistened a revolver. Tom ran the motor boat close alongside. With a snarl the man left off his sheet. The policeman and Dick Prescott leaped aboard the craft, Tom and Harry following. "This is a cheeky outrage!" snarled the skipper, scowling at the invaders. "Then keep the change, and welcome," laughed the policeman, taking his stand close to the skipper. Dick Prescott made a dive at the cabin door, which was closed.