The colored man started the pumps, and the professor watched the gages that told the depth of the craft. The pointer should have begun to swing around in a few seconds after the tanks began to empty. Instead it remained stationary.
"Strange," said Mr. Henderson. "I wonder if anything is wrong with the machinery."
"More like the whale, or whatever it is, is on top of the boat, holding her down," suggested Andy.
There was no doubt of this a moment later, for there were several violent blows on the upper part of the Porpoise.
The crew of the submarine were held prisoners below the surface by the unknown monster!
For a few minutes the thought of the awful fate that would be theirs if the ship should be wrecked under the water made each one speechless. As they stood looking at each other, not knowing what to do, the attack was renewed on the port side.
The big fish, whale or whatever it was, kept pounding away.
"I have an idea!" cried Andy suddenly.
"What is it?" asked the professor quickly.
"Let me put a diving dress on," began the old hunter.