n fleet.

The men of the _Dewey_ soon learned that the troopships which they
were escorting carried a number of regiments of marines and several
detachments of U.S. Regulars bound for France. Because the submarines
were slower than either the transports or the destroyers, the fleet
made slow progress.

They had been at sea over a week and were entering the war zone when,
late one afternoon, there came a sharp cry from the lookout in the
_Dewey's_ deck steering station.

"Periscope two points off the starboard!"

Instantly an alarm to general quarters was sounded. Jack and Ted,
detailed in the same gun crew, had just come on duty at the forward
gun. The _Dewey's_ wireless was flashing the news to the rest of the
fleet.

The destroyers drew in closer to the troopships and began immediately
belching forth dense black clouds of smoke under forced draft that the
boys divined instantly as the smoke screens used so effectively as a
curtain to blind the eyes of the U-boats.

Turning her nose outward from the hidden transports the _Dewey_ drew
away in a wide sweeping circle to starboard.

"All hands below!" came the order. Immediately the deck guns were made
fast and the crew scrambled down through the hatches. In a few minutes,
driving ahead at full speed, the _Dewey_ was submerged until only her
periscopes showed.

All at once the crew heard a shout from the conning tower.

"There she is!" yelled Lieutenant McClure, as he stood with his eyes
glued to the periscope glass.

"U-boat driving straight ahead at the smoke curtain. Port the helm!"
he commanded.

The _Dewey_ came around sharp and, in response to the guidance of her
commander, began to ascend.

Having executed a flank movement, the _Dewey_ now was endeavoring to
engineer a surprise attack on the German submarine from the rear. To
all intents, the German commander had not yet noted the approaching
American submersible. He was going after the transports full tilt,
hoping to bore through the destroyers' smoke curtain and torpedo one
of the Yankee fleet.

Quickly the _Dewey_ dived up out of the water, the hatches were thrown
open and the gun crews swarmed on deck, carrying shells for their
guns. Jack and Ted followed Mike Mowrey on deck and dropped into
position behind "Roosey." Gazing ahead they could make out the German
periscope and its foamy trail.

"Fire on that periscope," ordered Lieutenant McClure.

The U-boat was not more than nine hu