The term classic yachts invokes many images: long bow sprits, impeccable sheer lines and tiny transoms, teak decks, varnished trim, and sparkling brass. Some of the great sailboats come to mind: Altair, Lelantina, So Fong, and Ticonderoga, to name a few. But there are also the motor yachts such as Principia or the classic J boats Shamrock V and Endeavour. Some feel that classic yachts have to be at least fifty years old and built of wood, and while...