This mystery is set aboard a Royal Navy ship during a post-Revolutionary French-English conflict, but Patrick O'Brian it's not. Donachie is a competent but not inspired author whose work never rises above the level of cliche. Privateer Harry Ludlow encounters Oliver Carter, the captain who caused him to be cashiered from the service; when his brother James is accused of murder, Harry must investigate in the face of Carter's animosity. Carter's villainy is so firmly established at the beginning of the book that his partial redemption at the end is totally unconvincing. Despite the numerous "oh, nobody really minds" references to shipboard homosexual activity (too many; it has an air of protesting too much), the ending has a distinctly anti-gay tone.
What do You think about The Devil's Own Luck (1993)?