frequently promised but not yet realized joint family vacation.

The craft was equipped with twin gravitex stabilizers, mounted one on
each side of the hull. These gave it amazing smoothness even when
plowing through rough seas. They were adaptations of a device Tom had
invented for his space kite and _Cosmic Sailer_.

"Oh, what a gorgeous day for a sail!" Phyl said, aglow with enthusiasm.

The sky was a cloudless blue. Under a hot summer sun, a brisk breeze was
ruffling the lake into tiny whitecaps. The two couples cast off eagerly
and were soon scudding out across the water under full sail.

Tom and Bud wore swimming trunks under their slacks. Unfortunately the
girls had forgotten to bring their suits. When the _Sunspot_ reached the
center of the lake, the boys hove to, stripped down to their trunks, and
dived overboard. Meanwhile, the girls sun-bathed on deck. Soon it was
time for the picnic lunch, and all four ate with healthy young
appetites.

"Jeepers!" Sandy whispered to Phyl with a giggle. "After a feast like
this, we'll have to go on a diet!"

"Don't say it," Phyl warned, "or Tom and Bud will use that as an excuse
for never taking us out ag--"

She broke off with a gasp.

"What's wrong?" Tom asked.