Kammala jumla mai zuwa: Jirgin ruwa na gaba na Duff shine 50-gun, wanda ya shiga a 1755. Ya shafe shekaru da yawa yana tafiya, ko dai a matsayin mai zaman kansa ko a matsayin wani ɓangare na babban jirgin ruwa, kuma a 1758 ya kasance wani ɓangare na tawagar Commodore Richard Howe wanda ke kare dakarun da suka yi yaƙi da St Malo,
Cherbourg da kuma St Cas. Ya zama babban jami'in karamin rundunar soji da aka kafa a Brittany a 1759, yana kallon rundunar sojojin Faransa a Morbihan, yayin da rundunar sojojin karkashin Edward Hawke ta kewaye Brest, Faransa. Duk da yake a cikin Quiberon Bay a ranar 20 ga watan Nuwamba, 'yan kallo sun ruwaito wani babban jirgin ruwa na Faransa a kudancin Belle Île. Duff ya hanzarta rundunarsa, wanda ya kunshi jiragen ruwa guda 50 da kuma jiragen ruwa guda hudu, zuwa teku yayin da Faransawa suka bi su. Kafin a kama su, babban jirgin ruwa a karkashin Hawke ya zo ya mamaye Faransanci, ya ci su a cikin yakin Quiberon Bay.