The tried-and-true boat shoe is proving to be irresistible to designers, who cannot stop tinkering with the classic loafer and its white rubber sole. The latest versions are direct descendants of the original Sperry Top-Siders, created in 1935 by Paul Sperry. After watching his dog run over ice without slipping, Sperry developed a grooved rubber sole similar to his dog’s paws. Today’s boat shoes are as practical as ever but feature an array of design elements and colors that also make them a weekend wardrobe essential. From top: Ralph Lauren’s boat shoe ($325 per pair, www.ralphlauren.com) reflects the designer’s classic American style; Gucci’s tricolor leather shoe and neutral-suede loafer (both $480 per pair, www.gucci.com) bear the brand’s signature horse-bit hardware; Bally’s tricolor shoe ($450 per pair, www.bally.com) adds a penny-loafer detail; Tod’s blue boat shoe ($425 per pair, www.tods.com) is a trimmer version of the classic.