While Barton & Gray Mariners Club is my personal go-to for yacht charters, Dom Pérignon and chef Masa Takayama are making a splash with their custom cruises aboard an 88-foot San Lorenzo yacht around the waters of Sag Harbor and Montauk. More popular charters are Valkyrie Sailing, Yacht Kelpie and Shagwong Marina. B & G and Dom dock at various locations. 51 Division Street, Sag Harbor, N.Y., 11963. 51 Bay Street, Sag Harbor, N.Y. 11963. 219 Three Mile Harbor Road, East Hampton, N.Y., 11937.