“And a good line,” moaned Tubby.

“What are you kicking about?” demanded Merritt.  “It’s a lucky thing the beast didn’t start some plank of the boat when it charged; but as far as I can see, the Flying Fish stood the shock all right.”

“It felt like an earthquake,” murmured Hiram, whose face was white and eyes frightened.

“Well, I suppose we’d better head for home,” said Tubby at length.  “Those bluefish will go fine for supper.”

“Spoken like a Tubby,” laughed Merritt.  “All right, I’ll start up.  Hullo—­” he looked up with a puzzled face from the reverse lever.  “I can’t get her on the forward speed.”

“What’s the matter?” gasped Hiram.

“I don’t know.  Something’s stuck.  Shut off that engine, will you, Tubby, while I see?”

Tubby promptly shut down the motor, and Merritt struggled with the refractory lever.  It was all in vain, however; he could not get it on the forward speed.

“I’ve got to investigate,” puffed the perspiring corporal; “something must be wrong with the reversible propeller.”

“Well, whatever you are going to do, hurry up about it,” spoke Tubby, with unwonted sharpness in his tones.

“Why, what’s the—­” began Merritt.

Tubby checked him with a finger on his lips.

“Don’t scare the kid,” he whispered, leaning forward, “but we’re in for a storm.”

He pointed seaward.

Rolling toward them was a spreading wall of heavy clouds traveling at seemingly great speed, while below the wrack the water darkened ominously and became flecked with “white horses.”

CHAPTER XVI

LOST IN THE STORM

“The trouble’s in the reversible propeller.  I always told Rob he was foolish not to have a regular reverse gear on the shaft itself and a solid wheel,” said Merritt.

“Well, never mind that now,” urged Tubby anxiously.  “I’ll shift all the cushions and stuff up in the bow, and Hiram and I will get as far forward as we can.  That will raise the stern and you can hang over and reach the wheel.”

When the stout lad had done as he suggested there was quite a perceptible tilt forward to the Flying Fish, and Merritt, hanging over the stern, could feel about the propeller better.

“Just as I thought,” he shouted presently.  “That shark when he came astern fouled that heavy line on the propeller.”

He got out his knife, and in a few minutes succeeded in cutting the entangling line free.

It was not any too soon.  From far off there came a low sound, something like the moaning of a large animal in pain.  It grew louder and closer, and with it came an advancing wall of water crested with white foam.  The sky, too, grew black, and air filled with a sort of sulphurous smell.

“It’s a thunder squall,” shouted Tubby, as Merritt shoved over the lever and started the engine.