In a moment more young Somers was in the conning tower, and Jack,
sounding line in hand, was out on the platform deck, where Lieutenant
Danvers followed him.

Eph knew, by this time, what was wanted of him. Hal, in the engine
room, was, as yet, ignorant of the game, but all Hal had to do was to
obey engine room signals promptly.

Sending the submarine craft ahead at very slow speed, Eph steered as
close to the bobbing masthead as the young captain deemed safe. Jack
shouted his orders back as he and Lieutenant Danvers crouched over the
nose of the boat.

In the rough sea that was running their work was doubly hard. But Eph
kept the searchlight all the time turned in the direction of the top
of the bobbing mast stump. In a circle they went around it, barely
thirty feet from the broken mast, Jack heaving the sounding lead.

At last he felt it rest on the deck of the sunken derelict. The distance
below was six fathoms--thirty-six feet.

"Now, we've got the line of the hull," called Benson to the lieutenant.
"Our next job is to find how far back this hull runs under the water."

This knowledge, also, was gained, at last. Then Jack Benson, rising,
hastened back to the conning tower, followed by Danvers. Jack himself
closed the manhole, while Eph still trained the searchlight through the
darkness of the night. Stormy weather was threatening.

"Now, hustle below, Eph, and get that loaded torpedo into the tube,"