"Gentlemen," said the young commander after the crew had reached the deck, "this morning's work will undoubtedly be the real test. Within twenty minutes we'll be in the thick of a real fight!"

CHAPTER XIII

A BATTLE TRY-OUT FOR SOULS

Men had stood their watch by the guns all night long.

Boom! boom! From ahead came the sound of rapid firing. The commanders of the three leading destroyers were seasoned men experienced in their work, and were not likely to be shooting at mere shadows.

"At the best, it's snap-shooting," Dan uttered, almost disgustedly. "We cannot do our marksmanship justice when we are contending with a skulking enemy and seldom have anything more to aim at than a periscope that's up from four to seven seconds, or the wake caused by the conning tower of a submarine running near the surface."

"Occasional hits, however, show that a good deal can be accomplished by snap shooting when real gunners do it," rejoined Dave.

At this moment he read the signal for destroyers to maneuver at judgment. Dave promptly gave orders that sent the "Logan" scooting further away from the transport fleet, out on its port flank.

"Ahead, and zigzag," Darrin ordered sharply. "All the zigzag that full speed will allow."

Her turbines turning at better than trial speed limit, the "Logan"

roared on her way like an angry bulldog with the speed of a grayhound.

Despite the speed, the zigzagging course kept Dave opposite the troopship he had been guarding through the night.

Just astern of the "Logan" a periscope flashed up for a few seconds. A gun was trained and fired, but the periscope had been withdrawn by the time the sh.e.l.l got there. A tell-tale light streak appeared on the surface of the sea astern of the destroyer, one of whose signalmen waved a warning that was superfluous, for the troopship at which the torpedo had been aimed had already started off on a zigzag course, and escaped by a matter of feet.

From the head of the squadron came back the signalled order:

"All troopships zigzag!"

"Looks like a crazy marine waltz!" reflected Danny Grin as he caught a second's glimpse of this strange maneuver.

Darrin did not turn to see what had become of the submersible at which one of the "Logan's" sh.e.l.ls had been fired. The enemy was undoubtedly unharmed and under control, and there would be another destroyer on the spot in a jiffy. Dave believed that they were not yet in the thick of the Hun trap and he kept a sharp lookout ahead.

"Second destroyer astern of us just signalled a hit," Dan uttered presently, in a tone of glee.

"Must be the one that we tried for," was Darrin's comment.

In the meantime, both the British authorities and the American Admiral at the base port were being constantly informed, through radio messages, of just what was now taking place on this part of the sea.

"a.s.sistance already on the way; watch for it," came back the reply from the admirals.

"Humph! There's no vessel that sails that can reach us in season if it didn't start from port a few hours ago," was Dalzell's puzzled comment.

Not very long after that the leading ships of the fleet knew that they were in the thick of the enemy ambush. The courses of several torpedoes were observed, but, thanks to the zigzagging of the vessels, no transport or escort had yet been hit.

"Signal coming, sir, to commanding officer of the 'Logan,'" reported the signalman on the destroyer's bridge.

"'Logan' will drop out of line and hunt enemy submarines on commanding officer's judgment," Dave Darrin read.

"That's because of our record yesterday," Dan Dalzell chuckled. "We are looked upon as the star performers of the flotilla."

"We'll do our best to be the stars again to-day," Dave confided to his chum after he had given his orders.

With a rush and roar the destroyer headed northward, nor did Darrin come about until he was something like fifteen hundred yards away from the troopship line.

"Submarines usually try for hits at from six hundred to a thousand yards," he explained to Dalzell, as the racing craft hurried on her way.

"A German commander, with his eyes on the transports, might not think to turn his periscope in the opposite direction at a time like this."

"But his sound-detecting device will tell him where we are," Dan hinted.

"Not with all the gun-fire and the noise of so many hurrying craft,"

Dave answered. "Wait and see."

Phelps was sent to join the two seamen forward. From that position he could see any torpedo trail that started between the "Logan's" position and the transport fleet. Within less than five minutes Phelps detected a white line of seething foam, and Dave steered his ship straight to the spot where the Hun craft was believed to be.

"Fire as fast as you can, Mr. Phelps," was the order Darrin transmitted.

So closely had Phelps got the range that the "Logan" drove straight to the torpedo's source. There the long, vague outline of a submersible was barely discernible under the deep blue of the sea.

"Over her!" Darrin ordered.

At their station the depth bomb men stood at alert, awaiting the word at which the bomb would be released by the touch of a finger.

As the destroyer swept over the submersible's hull Dave shouted:

"Let go bomb!"

It was then that the finger touch was applied. Over the stern slipped the amazing mechanism which contained a steel sh.e.l.l. It was adjusted to go off automatically at a depth of thirty feet. Nothing within a hundred feet of the point of its explosion could escape being shattered.

b.u.mp! came a heavy explosion. The "Logan" herself shook and plunged as a column of water shot up astern.

Instantly Dave ordered the ship about, for the dropping of another bomb, in case the first had failed.

No need, though, for the spreading of oil on the surface of the water showed how effective a hit had been made.

"Now, for more of the pests!" uttered Dalzell, gleefully. "We must beat our record of yesterday."

Darrin did not reply. Outwardly calm, but with muscles set and every nerve tensed to the tingling point, he stood almost on tip-toe, grasping the forward rail, peering ahead and to either side.

But at least one German captain had caught him, so far out of line, for, from the starboard watch, forward, came the brisk warning:

"Torpedo, sir, on the starboard bow!"

In the same instant Dave had seen it. The trail was racing to meet the "Logan" well forward.