"You're crazy!" cried Andy. "You can't do it!"
"Just you watch," spoke Frank calmly. "I can't stand by and see a lad drown like that. Have we a spare line aboard?"
"Yes, plenty. It's up forward in the port locker under the deck."
"Good. Now I'm going to tie a line around my waist, and go overboard. I'll swim to that chap and get a good hold on him. Then it will be up to you to pull us both in, if I can't swim with him, and I'm afraid I can't do much in this sea. Can you haul us in, and manage the boat?"
"I've just got to!" cried Andy, shutting his teeth in grim determination. "The boat will ride all right out here. The wind isn't quite so bad now. Take care of yourself."
"I will. Shake!"
The brothers clasped hands. Frank well knew the peril of his undertaking, no less than did Andy. They stood on the heaving, sloping deck of the Gull, and looked into each other's eyes. They understood.
"Watch close, and pull when you see me wave to you," ordered the older lad, as he fastened the rope about his waist.
"All right," answered Andy, in a low voice.
With a quick glance about him, noting that the wounded lad was still struggling feebly in the water, Frank dived overboard. He disappeared beneath the green waves with their crests of foam, and for a moment Andy anxiously watched for his brother. Then he saw him reappear, and strike out strongly toward the other youth. Frank was an excellent swimmer.