Even in the fog the navigator found the harbor in question without
difficulty. Just as they would have apprehended the presence of a
submarine had one been near. There are very delicate and wonderful
instruments aboard American naval vessels--instruments that may not be
described at present--that enable the officers to apprehend the near
approach of other vessels and their own nearness to the shore as well.

The S. P. 888 made her landfall correctly and slipped into Rivermouth
Harbor like a ghost in the fog. There was a quantity of small shipping
in the place, and Ensign MacMasters did not want to take any chances of
collision. So he hailed a fishing smack and put the four friends from
Seacove aboard of her.

"Good-bye, boys!" he said, as they went over the side into the smack.
"We shall meet in a few days. You will get your notice by telegraph when
to join the _Kennebunk_, and where. I shall be relieved from the
command of this shark, and we'll have a big cruise on the
superdreadnaught, I have no doubt."

He spoke prophetically, as it was proved later. But at this time neither
Ensign MacMasters nor any of the four apprentice seamen imagined just
how wonderful a cruise it would be.

As the fishing smack chugged away with her auxiliary engine toward the
docks of the town, the S. P. 888 swung in a narrow circle and put out to
sea so swiftly that in five minutes she was completely out of sight in
the fog and almost out of sound as well.

The fishermen were curious about the boys and the business of the chaser