This novelette (it's only about 75,000 words long) uses a tired old trope thought up by the Victorians - the distraught wife disguising herself as a man to run off to sea and find her husband/lover. Certainly women DID dress up as men and serve in Nelson's navy, but the usual motivation was a desire for adventure combined with freedom from the socially limited options then available to the female gender.
However, in spite of the premise, this is a really good novel, a definite page-turner. It's well written and it's historically very accurate. The mores and attitudes of the time are correctly portrayed, and yet this is done in a way that still makes it accessible to a modern reader, which is a very difficult thing to do. Moreover, Beryl Kingston does not make the mistake of overcooking the ingredients. Our heroine and hero do typical rather than extraordinary things. They come into contact with the famous and the powerful occasionally, rather than those people being totally beholden to them. It's a fundamentally optimistic book too, showing the good rather than the bad in people. It is, in the classic meaning of the term, a true romance.
The speech patterns of the characters are particularly well done. Strong accents are interesting and help to identify characters and time periods. They are also notoriously difficult to pitch correctly. Too little and the period feel dissipates. Too much and the characters become unintelligible. The author has them just about perfect here. Read it. You will not be disappointed.