l from the lookout aft.

"Submarine off the stern, sir!"

At the same moment the battery in the Brigadier's turret aft burst into
action.

"Forward with you, Mr. Chadwick," cried Jack, "and see if you can't get
better results there. The men seem to have lost their nerve."

Frank sprang forward. Jack's words were true. It appeared that the crew in
the forward turret were so anxious to sink the first submarine that they
had not taken time to find the range.

"Cease firing!" shouted Frank as he sprang into the turret.

The order was obeyed, but there came a grumble from the men at what they
deemed such a strange command under the circumstances.

"I thought you fellows were gunners," said Frank angrily. "Smith, get the
range."

Smith did so, and announced it a moment later.

"Now," said Frank, "get your aim, men."

No longer was there confusion in the forward turret. The guns were trained
carefully.

"Ready," cried Frank. "Fire!"

"Crash!"

A moment and there was a loud cheer from the crew. The German submarine
seemed to leap high from the water, and then fell back in a dozen pieces.

Frank wasted no further time on the first submarine. Leaving the forward
turret, he dashed aft to where other guns were firing on the second
submarine. Meantime Jack, perfectly cool on the bridge, had maneuvered his
vessel out of the way of several torpedoes from the second U-Boat. But,
as he very well knew, this combat must be brought to a quick end or one
of the torpedoes was likely to find its mark.

From the deck of the second submarine, a hail of fire from a machine gun
was still being poured into the helpless lifeboats. What execution had
been done Jack had no means of telling at the moment, but he knew there
must have been some casualties.

"The brutes!" he muttered.

The duel between the submarine and the destroyer still raged. It appeared
that the commander of the submarine was a capable officer, for he had
succeeded in keeping his vessel from being struck by a shell from the
Brigadier.

In the aft turret of the Brigadier the British tars were sweating and
muttering imprecations at their inability to put a shell aboard the enemy.

"Here," said Frank, "let me get at that gun."

The crew stepped aside and the lad sighted the weapon himself. Then he
fired.

Again a cheer arose aboard the Brigadier. Frank's shot had been
successful. The shell struck the submersible squarely amidships, and
carried away the peris