The Rosinco was a notable diesel-powered luxury yacht with a rich history spanning construction, military service, and maritime exploration. Built in 1916 by Harlan and Hollingsworth in Wilmington, Delaware, she measured approximately 95 feet in length and featured a steel hull constructed with seven watertight compartments divided by six bulkheads, enhancing her seaworthiness and safety. Her hull included a vertical through-plate keel measuring 0.5 inches thick, merging under the machinery, with upper decks fashioned from narrow white pine planks edged by mahogany. Powered originally by a Southwart-Harris 240 horsepower diesel engine—an innovative feature at the time—she could accelerate from a cold start in ten seconds and shift from full ahead to full astern in five seconds. The engine, equipped with four cylinders each 9 inches in diameter with a 13-inch stroke, allowed rapid maneuverability and was complemented by a 3-kilowatt electric generator. Her propeller was 4 feet in diameter with a 60-inch pitch, and her fuel capacity was 1,070 gallons of crude or fuel oil. Initially named Georgiana III, she was designed for use on the Delaware Bay and launched on 20 May 1916, representing one of the finest examples of motor yacht construction of her time. She was registered with U.S. Official Number 214160 and served as the third yacht for William G. Coxe. Her interiors featured mahogany-paneled deckhouses, a main salon with oak paneling and English tapestry, and a grand stateroom equipped with a 3/4 bed, Pullman bed, and dressing facilities, emphasizing her luxury status. During World War I, the yacht was acquired by the U.S. Navy under a free lease, commissioned as USS Georgiana III (SP-83), and served in the 4th Naval District. Her duties included harbor entrance patrols at Cape May, Delaware Bay, and escorting ships with underwater listening gear. After decommissioning in late 1918, she returned to civilian ownership, renamed Whitemarsh in 1918, and later Rosinco in 1925, when she was fitted with a Fairbanks-Morse Model 35 diesel engine. Her final voyage in September 1928 ended tragically when she struck a raft of wooden beams on Lake Michigan near Kenosha, Wisconsin, rupturing her hull and sinking rapidly. The wreck, lying upright at 190 feet beneath the lake's surface, remains well-preserved in the cold freshwater environment. Recognized for her historical significance, the Rosinco wreck was added to the National Register of Historic Places in 2001, and she continues to be a subject of archaeological research and maritime heritage preservation.

This description has been generated using GPT-4.1-NANO based on the Vessel's wikidata information and then modified by ShipIndex.org staff.