ie, crowding close to the lad lying on the
locker. "What's that you're saying about the 'U-13'?"

"I say 'Look out for it,' that's all!"

"No, it isn't all!" protested the boy. "Take another drink of this coffee
and then brace up and tell us what you know! How did you get here and
what and who and where and why is this 'U-13'?"

Frank smiled as he struggled to a sitting posture.

"If you'll rub the cramp out of that leg, boys, I'll 'fess up'
everything," he began. "That leg feels as if some one were trying to pull
some teeth out of it by the roots. A cramp is fierce."

Two lads began massaging the offending member.

"If I'd known it was you swimming to us, I'd have lowered a boat myself
and come to your assistance!" declared Jimmie.

"And if I'd known you were on board this schooner," replied Frank, "I'd
have left that ship long before I did!"

"Why, what's the matter on that ship, Frank?" asked Ned.

"Oh, nothing, only it's one of these 'work-houses' just exactly like we
have read of. The captain is a hard nut and the mates are both of the
'bucko' type. There isn't a man aboard who hasn't got a mark from one or
the other of the mates. They're a tough crowd!"

"I'll bet you didn't just fall overboard, then!" shrewdly guessed Jimmie.
"You missed your footing purposely! You know you did!"

"How do you know?" grinned Frank, nursing his cramped leg.

"I was watching through the binoculars," answered Jimmie. "But go ahead
and tell us something. We're dying from curiosity!"

"Well," began Frank, "you know I wasn't quite satisfied to be left behind
when you four lads left in chase of the fellow who had stolen the Panama
plans. I wanted to go along in the Grey Eagle."

"We know that, and we're sorry we didn't take you!" cried Ned.

"I went to see Mr. Bosworth about following you," continued young Shaw.
"He was opposed to that plan, but you know I usually get my own way
somehow. I put together a kit and started out. I had little difficulty in
securing passage on a ship loaded with miscellaneous cargo for England.
The vessel was a British tramp--a 'bucko' ship.

"We got close to Land's End after a rather uneventful voyage across the
Atlantic. I was dreaming of getting ashore in a short time and then
hiking across the channel into France to hunt you up.

"One fine morning we were all startled to hear a hail from the lookout
informing the deck that a submarine was approaching. We hove to at the
command of the sub