“That’s not as bad as it might be, is it?” queried Hastings, as soon as they were back on board the “Farnum.”

“We’re on probation,” smiled Jack.  “It’s all we can expect, I suppose.”

In due time the section of naval cadets came on board.  Mr. Mayhew was also thoughtful enough to send a naval machinist to take the place of Sam Truax in the engine room.  Thus Hal had two men to look after the motors and other machinery under his direction, leaving Eph at Jack’s more personal orders.

“The lieutenant commander sends you word, with his compliments,” reported Ensign Trahern, “that, after leaving the bay, the formation will be as usual.  The signal to halt and be ready for the tour of instruction will be given when we are about ten miles off the coast, due East.”

“Mr. Trahern, will it not be a good idea to have the midshipmen manage the deck wheel and engine room signals, each in turn, on the way out and back?” inquired the young submarine skipper.

“Excellent, I should say,” nodded the ensign.  “But that is as you direct, Mr. Benson.  I am not here to interfere with your acting in full charge of the instruction tour.”

Six of the cadets, of the engineer division, being below in the engine room, there were but ten on the platform deck.  Jack selected one of the latter, ordering him to the deck wheel.

“You will take charge, Mr. Surles,” instructed Jack.  “Assume all the responsibilities of the officer of the deck.”

When the starting order came from the gunboat, just before the “Hudson” glided ahead in the lead, Mr. Surles gave the order to cast loose from moorings.  The engine room bell jangled; Surles, for the first time in his life, was watch officer of a submarine torpedo boat.

As they left the bay behind, the young man gave up his temporary post to a comrade.  In all, five of the midshipmen commanded, briefly, before the laying-to signal was given out at sea.

Hal Hastings now appeared on deck, gravely saluting.

“Captain Benson,” he stated, “I have inspected all the submerging machinery, the tanks, the compressed air apparatus, and all, and find everything in good order.  We can go below the surface at any moment.”

Two or three of the naval cadets smiled broadly at hearing the title bestowed on a boy younger than many of themselves.

“No levity, gentlemen,” broke in Ensign Trahern, rather sternly.  “Mr. Benson is captain to his own chief engineer.”

Jack waited until he saw the signal flags break out at the foretop of the “Hudson.”  It was an inquiry as to whether he was prepared for diving.

“Yes,” signaled back the “Farnum’s” flags.

“Dive at will, but keep to a due east or west course.  Be careful to avoid collision with the sister craft,” came the next order from the parent boat.

“All below!” ordered Benson, crisply.

Ensign Trahern waited until the last of the cadets had filed below, then followed them.  Last of all came Jack Benson, after having lowered the short signal mast and made other preparations.  Now he stepped inside the conning tower, swiftly making all fast.  Then he called Midshipman Surles up the stairway to the tower wheel.