"Cape Horn marks the spot where the Pacific and Atlantic Oceans meet in one writhing mass. The weather is usually atrocious." That's how maritime historian and diver Charles Lagerbom describes the waters off the southern tip of South America. He knows from experience. He's been to the Horn studying shipwrecks. Among his many interests are Maine-built ships and Maine seafarers who doubled the Horn, or were lost battling the Horn, taking a prominent place in the maritime history of Maine, the nation, and the world.