es were secured.

Rick and Scotty paddled the boards to the extreme length of the lines,
then separated as much as the lines allowed. They were about thirty feet
apart and a hundred feet behind the boat.

They waved their readiness to Tony, who relayed the go-ahead to Zircon.
The boat started slowly.

Rick moved forward on his board, and the weighted board tilted down. It
acted as a hydrofoil, its forward motion pulling it deeper into the
water. Rick waited until he was only ten feet from the bottom, then
shifted his weight back again. Obediently the board tilted upward and
raced for the surface. Rick moved forward again just in time to keep
from breaking through the surface. By adjusting his weight, he could
keep the board level, or go up or down. It wasn't easy and he had to
fight the board level almost constantly.

Bubbles rose from the regulator between his shoulder blades as he
breathed rhythmically. The lung performed effortlessly, giving him as
much air as he needed. He felt the pressure on his ears as he steered
the board toward bottom, and there was an instant of pain before his
ears adjusted.

The bottom was sandy. To his right he saw the wall of the reef, and once
a startled snook shot out of his way. To his left he could see Scotty.
Before he knew it the boat had throttled down, a signal that they were
at the southern end of the reef. He tilted upward and surfaced.

Tony called, "How is it?"

"Great!" Rick called back. "But we'll need lots more line. It was
shallow on the way down, but if we try to go any deeper the angle of the
line will make the boards come up."

"You should try it," Scotty said. "Honestly, Tony, it's wonderful!"

"I'll try it a little later," Tony promised. "I'm giving you all the
line we have, about three hundred feet each. If you can't make it,
surface. We'll have to splice the two lines together and use just one
board."

Zircon came to the stern and bellowed, "You forgot these!"

He tossed in two fishing floats and coils of line. Those were in case
they found the wreck. Whoever spotted it was to drop off his board,
secure the line to the wreck, and let the float rise to the surface. In
that way, they would have a guide.

Each boy took one of the units and fastened it to his weight belt.

"We're off!" Zircon called. "Ready?"

The boys yelled that they were. Rick fitted his mouthpiece and checked
the seal of his mask. Scotty did the same, then both tilted their boards
a