Under the Jolly Roger by L.A. Meyer

Ah-hoy! Jacky is back. Jacky Faber has made her way back to London by working on a whaleship. She'll do whatever it takes to get back to her beloved Jaimy. But, due to a misunderstanding -- so common for our Jacky -- her reunion with Jaimy is a disaster. And it leads to poor Jacky being pressed into service on a war ship. She is sure she will be released as soon as it is discovered that she is a female but Jacky just doesn't have that kind of luck. She finds herself as a midshipman on a ship with a cruel captain with none so pleasant plans for her. Through her cunning and a little bit of good luck, Jacky finds herself the captain of her own ship. But, good things never seem to last for Jacky. And what of poor Jaimy?