Sharpe's Trafalgar by Bernard Cornwell
The seventeenth Sharpe novel sees Sharpe returning from India to London to join the newly formed Green jackets. Sharpe, though a little more comfortable with his new officer rank, is sure that this new unit is of lower status, and that he has failed. His ship home is shipwrecked: he is captured by pirates but fighting free with a few companions, finds himself on a British Navy ship heading to join Nelson's fleet. And there, in October 1805, he finds himself involved in the great sea battle, and discovers new skills in fighting on sea.