, is joined to the shaft of the engine by a coupling, or
sleeve. If you take two lead pencils, and thrust an end of each into
each end of a hollow, brass pencil holder, you will get an idea of what
I mean. One pencil will represent the shaft to which the propeller is
fastened, and the other the engine shaft. The brass holder is the
coupling, or sleeve. In order that the shafts will be held rigidly
together, turning at the same time, set screws in the sleeve are tightly
turned down on the shaft, binding both in the sleeve.

It was the set screws on the propeller shaft that had loosed, allowing
the sleeve to slip uselessly around, that had caused all the trouble.
With a wrench Russ tightened the screws. He tested them, and, finding
them firm, started the engine. A moment later the _Ajax_ was moving over
the waves under her own power.

"Hurray!" cried Mr. Sneed. "This is great!"

"And we don't need this any longer," Russ said, hauling in the drag
anchor. Then, able to mount the waves, the motorboat was in much better
condition for fighting the storm.

On and on she rushed. Hour after hour passed, but the gale showed no
signs of abating. The two young men were weary and disheartened, when,
as there came a little rift in the clouds Russ, who stood up to look
about, gave a yell.

"What is it now?" asked Mr. Sneed. "More trouble?"

"No!" cried Russ. "I see a steamer. Help at last! I'm going straight for
her!"

CHAPTER XXIV

A SIGNAL OF DISTRESS

Russ had been running the motor at moderate speed, for he did not know
just how long the supply of gasoline would last, and he did not know as
yet what might be before him and his companion in distress. But the
sight of the steamer gave him hope, and he turned on full speed.

The _Ajax_ was a powerful craft, though even a mighty steamer would not
have found it easy to make headway in that sea and in that gale. The
motor craft responded gallantly, and shot up on the crest of each wave,
sliding down the opposite side as though she were going to investigate
the uttermost depths of Father Neptune's caverns.

"Steamer! I don't see any steamer!" exclaimed Mr. Sneed, as he looked in
the direction toward which the face of Russ was turned.

"You will when we both come on top of a wave at the same time," was the
answer. "You see we lie so low in the water she can't see us, and we
can't glimpse her until we're both on a crest together. She's off to the
east there. Watch and