 New Jersey fired on coastal batteries and buildings at Kojo 16 April ; on railway track and tunnels near Hungnam 18 April ; and on gun emplacements around Wonsan Harbor 20 April , silencing them in five areas after she had herself taken several near misses . Songjin provided targets 23 April . Here New Jersey scored six direct 16 inch ( 406 mm ) hits on a railroad tunnel and knocked out two rail bridges . 
