It presumably means "new to the singer". But it seems unlikely that, whatever his age, he has only just discovered the supposed consolations of alcohol. I really can't think that will do as an explanation. The DT version, under somewhat odd title of "Drive Sorrows Away", altho it attributes to the Coppers, begins differently: "You see we poor sailors", rather than "The time passes over" [although another crux in that version would be how sailors, presumably at sea while singing, would be found "at home"!]. But I agree that the lyric as a whole doesn't furnish much clue as to what the "new act" might be. I can't think of any which sailors or landsmen would only just have "found".

~M~