The four boys, at that time all under eighteen years of age, had begun their first enlistment in the Navy several months before the United States got into the war.  They spent some months in the training camp at Saugarack, on the New England coast.

The Government commissioned new craft of all kinds as rapidly as they could be obtained, and was obliged to man some of them partly with youths who had not yet finished their preliminary training ashore.

Phil Morgan and his friends had made rapid progress in their studies and the drills, and they were lucky enough to be assigned to the same ship.  This was the destroyer Colodia, one of the newest of her class, a fast ship of a thousand tons’ burden.  She made two cruises, both crammed full of excitement and adventure; and the story of these cruises is related in the first volume of the series, entitled “Navy Boys After the Submarines; Or, Protecting the Giant Convoy.”

In this first narrative of their adventures in the United States Navy, Phil had a very thrilling experience.  He fell overboard from his ship and was picked up by the German U-boat No. 812.

After the conclusion of the destroyer’s second cruise the four chums from Seacove were enabled to spend a week at home.  Returning to the port in which they had been instructed to join the Colodia the evening before she again was to sail, the four chums were held up by a burning railroad bridge, which had been set on fire by German agents.

It looked as though they would be unable to reach the Colodia on time.  This event would be a very serious matter, for the naval authorities frown upon any tardiness of enlisted men in returning from shore leave.  Besides, the boys particularly desired to be aboard the Colodia during her coming cruise.

The second volume of the series opened with this situation.  The boys made the acquaintance of an influential man, Mr. Alonzo Minnette, who was likewise a passenger on the stalled train.  And he made it possible for the four apprentice seamen to reach their ship in time.

In this second volume entitled:  “Navy Boys Chasing a Sea Raider; Or, Landing a Million Dollar Prize,” the four young members of the Colodia’s crew, whose adventures we are following, had many thrilling experiences.  In the end, the destroyer, by a ruse, captured the Graf von Posen, a noted sea raider, and Whistler and his chums are allowed to board her as part of the prize crew.

The boys were particularly interested in the cargo of the raider, for Mr. Minnette had promised them a thousand dollars to divide among them if they discovered aboard the raider the treasure of the Borgias, a collection of precious stones, that the captain of the Graf von Posen had taken from an Italian merchant ship which had been captured and sunk by the Germans.

Naturally the Navy boys were interested in having others join the Navy; and Hans Hertig, whom they found at home visiting his mother, was particularly anxious to get some young men, who were working in Elmvale and who came of German stock like himself, to enlist and show their patriotism and love for the country of their birth.