From bilge to beauty"" during one of those lakeside summers, but better than most because of the crisp dialogue. At fifteen Tomboy Terry would rather fight than switch and it takes most of July to change her outlook. The old gang's drifted to other shores and renters are notoriously hard to take; even cockier is Carl Larson, inveterate womanhater and determined skipper without a crew. A Miss America type next door breaks the barrier with Carl while Terry makes a deal with shorter, lighter and younger Norman for the dance. ""I look like a double lime popsicle on two sticks. Melting,"" says Terry, in her first attempt at femininity. But she sticks it out, has it out with Carl, and is not the belle of the ball. Fewer exclamation points than usual, and more good humor.