"See that you do. See that you do," said his grandfather as he turned to the house and left the boys standing on the dock.
"All the same," spoke up George, "I'm sure that that collision wasn't any accident. What do you think, Grant?"
"I confess I don't know," replied Grant. "If it was the only thing that had happened I might think it was an accident, but taken in connection with some other things we have found out, I'm almost afraid it wasn't."
"Then the only thing for us to do," said John, "is to keep watch. Sam is going to bring the Black Growler back here to-night and some one of us will have to be on guard all the time."
"I have got that all fixed," said Fred, taking a slip of paper from his pocket as he spoke; "I have divided the night into five watches. We'll let Sam stay on guard until eleven o'clock. I'll take the watch from eleven P. M. to twelve-thirty A. M. Grant can come on at twelve-thirty and stay until two, then George will take his place and stay until half-past three. John will be the last one and he can be the guard from half-past three until five o 'clock. There won't be any need of any one after that because it will be light by that time."
"That's all right," spoke up George. "The only suggestion I have to make is that we rotate the hours, if we keep this up many nights."
"What do you mean?" inquired Fred.
"Why the one that comes on at eleven o'clock one night comes on at twelve-thirty the next night. The one who comes on at twelve-thirty will report at two and so on. We'll just keep pushing the schedule up every night so we'll all be the same when we're done."
"How shall we know when our turns come?" inquired John.
"Every fellow is to call the one who is to take his place."