High Quality Content by WIKIPEDIA articles! The USCGC White Alder (WLM/WAGL-541) was the former Navy lighter, YF-417. The United States Coast Guard acquired a total of eight of these former Navy YF-257-class lighters between 1947-1948 for conversion to coastal buoy tenders. They were needed to complement the larger seagoing buoy tenders in servicing short-range-aids-to-navigation, typically those placed in coastal waters and harbors.