USS Avenger (SP-2646) was an armed motorboat that served in the United States Navy as a patrol vessel in 1918. The second Avenger, a wooden-hulled screw yacht designed by J. Murray Watts and built in 1917 by Clement A. Troth of Camden, New Jersey, was inspected by the Navy on 11 January 1918 and acquired by the Navy in May 1918 under free lease from Philips J. Wunderle of Glenside, Pennsylvania, for service in the 4th Naval District. Assigned the identification number SP-2646, Avenger was commissioned on 29 May 1918 while she lay alongside Pier 19, North Wharves, Philadelphia, Pennsylvania, with Chief Boatswain's Mate Philips J. Wunderle, USNRF (her peacetime owner "called to the colors"), in command. Service history Completing the initial phases of her fitting out by the second week of June 1918, Avenger got underway for League Island on the morning of the 10th. She did not go far before she ran aground in shoal water near the back channel. With low water prevailing, her sailors prepared to wait for the incoming tide to refloat Avenger, but three vessels unexpectedly arrived on the scene and offered assistance. With their help, Avenger was soon waterborne and proceeded to League Island. However, since she was shipping water due to two damaged tanks in her bottom, the yacht proceeded thence to Camden, New Jersey, for hull repairs at the boatyard of Quigley and Dorf on 11 and 12 June. After receiving new planking and a coat of paint on her bottom, she returned to Pier 19, North Wharves, the next day, 13 June. A week later, the vessel got underway at 1000, "Captain" Wunderle at the helm, and headed back toward League Island, where she took on board her main battery, a three-pounder gun, and installed it the next day. Further provisioning and outfitting alongside Pier 19 followed: there, she received the balance of her armament, a pair of machine guns and four mounts, on 5 July. She obtained signals equipment and a large searchlight on the 11th and left Pier 19 the next day for Fort Mifflin, where she took on ammunition. Later that same day, Avenger got underway for New Castle, Delaware, reaching her destination that evening, and tarried there for the night. Pushing on the next day, Avenger reached Cape May, New Jersey, her assigned section base, on the 13th, via Reedy Island. The following morning, the erstwhile