Roman numeral depth markers on stern end of the historic Balclutha sailing ship - Stock-Fotografie

Balclutha is also known as Star of Alaska. It was built in 1886. It's a cargo ship that transported cargoes such as coal, wine, and grain. She's a U.S. National Historic Landmark now moored at Hyde Street Pier of the San Francisco Maritime National Historic Park, San Francisco, California. She was added to the National Register of Historic Places on November 7, 1976.