Sharpe's Trafalgar by Bernard Cornwell

This is the best I've encountered in the Sharpe's series - very enjoyable. PW A guttersnipe who has risen through the ranks of the British army, Ensign Sharpe is sailing home to England from his latest campaign against Napoleon. Anticipating an uneventful voyage, the dashing young maverick discovers the intriguing and very married Lady Grace Hale on board the Calliope. But just as he wins his way into her heart, the ship is fired upon and, suddenly, he finds himself in the thick of one of history's most spectacular incidents: the Battle of Trafalgar.