“Aye, aye, sir.”

“My compliments to Mr. Hastings, and ask him to crowd the speed of the boat gradually.”

“Aye, aye, sir.”

The “Dodger” had been moving down the bay at a ten-knot pace.  Suddenly she gave a jump that caused Midshipman Dave Darrin to wonder.  Then the submarine settled down to a rushing sixteen-knot gait.”

“I didn’t know, sir,” ventured Farley, “that submarines could go quite so fast.”

“The old types didn’t,” Lieutenant Jack answered.  “However, on the surface a capable submarine must be able to show a good deal of speed.”

“For getting away, sir?”

“Oh, no.  Naturally, when a submarine is pursued she can drop under the surface and leave no trail.  But suppose a single submarine to be guarding a harbor, unaided by other fighting craft.  A twenty-or twenty-two knot battleship is discovered, trying to make the harbor.  Even if the battleship steams away the submarine should be capable of following.  The engines of the ‘Dodger,’ in favorable weather, can drive her at twenty-six knots on the surface.”

“She’s as fast as a torpedo-boat destroyer, then, sir,” hazarded Dan.

“Yes; and the submarine needs to be as fast.  With the improvement of submarine boats the old style of torpedo boat will pass out altogether.  Then, if the destroyer is retained the submarine must be capable of attacking the destroyer on equal terms.  Undoubtedly, after a few years more the river gunboat and the submarine torpedo boat will be the only small fighting craft left in the navies of the leading powers of the world.”

Even while this brief conversation was going on the speed of the “Dodger” had begun to increase again.  Ensign Hasting’s head showed through the opening in the conning tower.

“We’re going now at a twenty-knot clip, sir,” Hal reported.  “Do you wish any more speed?”

“Not in Chesapeake Bay; navigating conditions are not favorable.”

“Very good, sir.”  Hal vanished below.  Never very talkative, Hal was content to stand by his engines in silence when there was no need of talking.

From time to time, as the craft sped on down the bay, Lieutenant Benson glanced at the chronometer beside the deck wheel.

“You don’t have the ship’s bell struck on this craft, sir?” inquired Midshipman Darrin.

“Only when at anchor or in dock,” replied Lieutenant Jack Benson.  “A submarine’s natural mission is one of stealth, and it wouldn’t do to go about with a clanging of gongs.  Now, let me have the wheel, Mr. Darrin.  You gentlemen go to the conning tower and stand so that you can hear what goes on below.”

While the three midshipmen stood as directed the speed of the “Dodger” slackened.

Then, after a space of a full minute, the submarine returned to her former twenty-knot speed.

“Did you hear any clanging or jangling of a signal bell or gong when the speeds were changed?” questioned Lieutenant Benson.