Keywords: Mark 87 gun fire control system optical unit on USS Ready (PG-87) in 1974.jpg The optical unit of the Mark 87 gun fire control system in use aboard the U S Navy patrol gunbaot USS Ready PG-87 during a missile-firing exercise 9 July 1974 Official U S Navy photo http //www history navy mil/our-collections/photography/numerical-list-of-images/nhhc-series/nh-series/NH-88000/NH-88424 html NH 88424 from the U S Navy http //www history navy mil Naval History and Heritage Command 1874-07-09 U S Navy PD-USGov-Military-Navy USS Ready PG-87 |