The USS Zenith (SP-61) was an armed motorboat built in 1917 by the Mathis Yacht Building Company in Camden, New Jersey. Designed by Bowes and Mower of Philadelphia, the vessel was originally constructed as a yacht for Charles Longstreth of Philadelphia, a prominent yachtsman and Commodore of the Corinthian Yacht Club. The design received approval from naval authorities, with the potential for reserve service, and the vessel was turned over to the Navy just before its completion. This made Zenith the second vessel owned by Longstreth to serve in the U.S. Navy, following USS Arawan II (SP-1). Constructed for speed and agility, Zenith was powered by two 400-horsepower, eight-cylinder Duesenberg diesel engines, allowing an estimated maximum speed of approximately 30 miles per hour. Her dimensions, armament, and crew complement reflected her role as a patrol vessel; she was equipped with one 3-pounder gun positioned forward and two machine guns mounted aft, with a crew of nine men. Commissioned into the Navy on 23 April 1917 and designated SP-61, USS Zenith was assigned to section patrol duties within the 4th Naval District, which covered the coastlines of Pennsylvania, Delaware, and southern New Jersey. Her primary mission was to conduct surveillance patrols aimed at safeguarding harbors and estuaries from potential enemy threats, including submarines and minelaying operations, during World War I. USS Zenith served diligently until the end of hostilities on 11 November 1918. She was decommissioned shortly afterward on 21 November 1918, and her name was struck from the Navy list the same day. The vessel was then returned to her owner, marking the end of her brief but active service in wartime patrol operations. Her service exemplifies the rapid conversion of private yachts into naval patrol vessels during World War I, highlighting her maritime significance as a swift, agile defender of U.S. coastal waters during a critical period.

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