By Steve Gorman

Nov 11 (Reuters) - Famed ocean liner SS United States, the largest passenger ship ever built in America and the world's fastest, headed for the sea floor near Florida on Wednesday in a deliberate sinking designed to transform the vessel into the world's biggest artificial reef.

The finale to a ‌yearlong process preparing the ship to meet its destiny, 75 years after it was first launched at sea, was presented in a livestream with aerial views of ‌the once-grand vessel's rusted hulk, stripped of its two smokestacks, quietly, slowly settling into calm waters of the Gulf of Mexico before succumbing to the deep.

The ship, measuring nearly 1,000 feet (300 m) from stem to stern, was ​surrounded by onlookers and safety crews aboard dozens of tugboats and recreational vessels that accompanied the ocean liner as it was towed out to sea for its final voyage.

By then, work crews had...