Rubuta ci gaba ga wannan sakin layi - alƙawari na gaba na Lockhart ya kasance zuwa 66-gun a watan Afrilu 1747. "Devonshire" shi ne babban jirgin ruwa na Rear-Admiral Peter Warren, wanda Lockhart ya yi aiki a yakin farko na Cape Finisterre
a ranar 3 ga Mayu, 1747. Daga nan sai aka nada shi zuwa kwamandansa na farko, na fireship, wanda ya ga aikin tare da rundunar jiragen ruwa na Sir Edward Hawke a yakin na biyu na Cape Finisterre a ranar 16 ga Oktoba, 1747. Ɗaya daga cikin kyaftin din a cikin yakin, Thomas Fox na 64-gun, daga bisani ya sauke daga umurninsa bayan rikice-rikice game da ayyukansa a cikin yakin, kuma an ba Lockhart umurnin wucin gadi na "Kent" a wurinsa. A lokacin 1748 Lockhart shi ne na farko na Portsmouth guardship, kuma a cikin 'yan shekaru masu zuwa ya kasance a kan rabin biya a Scotland. A watan Janairun 1755 an nada shi na farko a cikin bindigogi 90 tare da Kyaftin Charles Saunders, kuma a ranar 22 ga Afrilu 1755 an daukaka shi zuwa kwamandan jirgin ruwa mai bindigogi 8, wanda aka haɗe a cikin shekara zuwa jirgin ruwa na yammacin da ke karkashin jagorancin Sir Edward Hawke ko Mataimakin Admiral John Byng.