Bang! bang! bang! Destroyer and troopship guns, up near the head of the line, had suddenly begun blazing away.

Half a dozen periscopes showed short lengths, briefly, above the water, but the number of faint streaks across the sea showed that other enemy submarines were attacking without first taking periscope sights.

“It’s the general attack on the fleet, that we expected!” Dave Darrin shouted from the bridge. “Stand by! Remember that fractions of seconds count in carrying out orders now.”

Then Lieutenant Beatty caught sight of a periscope above the water, some eight hundred yards away. One of the “Logan’s” forward guns spoke in sharp challenge. The biggest submarine sea fight of all was now on!

[CHAPTER X—THE HOTTEST WORK OF ALL]

From the troopship line, as the “Logan” dashed away, Darrin could hear the guns of the transports that were coming up and near enough to take part in the fight. Wherever a periscope showed itself it was bound to invite fire from half a dozen gunners in almost the same instant.

“Sorry, but you soldiers will all have to go inside and remain there,” ordered Lieutenant Dan Dalzell. “We have no room for any one on deck except our crew.”

To most of the soldiers it seemed hard to be deprived of a view of the only thing that interested them, but Navy officers, in issuing orders, have a way of speaking that does not admit of doubt as to their meaning.

“There goes the ‘Castle City’ by the bow,” called a lookout, but Dave Darrin, his eyes searching for a torpedo trail, took his word for it and did not turn to look.

“Torpedo wake, sir, three points off port bow!” sang out a lookout.