The afternoon is overcast, the ocean churning, between Port Fairy and Warrnambool, on the Shipwreck Coast of Victoria, Australia. A man and woman carry shovels and a metal detector along the beach. I ask if they are looking for Warrnambool’s notorious wreck, the Mahogany Ship. Without hesitation, the man answers: “I’ve been searching for the Mahogany Ship for 15 years.” The Shipwreck Coast is a dramatic 80-mile stretch of jagged cliffs and deep gorges, limestone formations and towering dunes. It is estimated that nearly 700 ships wrecked along this coastline…