Forever Leftenant Rundel (book 5 of 9 of the Rundel Series)

Benjamin Rundel is second leftenant aboard the Gadfly, which is under the command of the son of an M.P. who has bought his son’s commission. But the young captain is a frustrated actor who is addicted to opium and has no idea of the duties of captain. Ben must face charges of mutiny in order to safeguard the ship as he assumes the captain's duties. This is book 5 of 9 in Stark's Rundel series.