Who is Captain Peculiar Cromwell from Sharpe's Trafalgar: Richard Sharpe and the Battle of Trafalgar, October 21, 1805 and what is their importance?

Captain Peculiar Cromwell is the captain of the "Revenant." He is an experienced seaman with a good reputation. When the ship encounters pirates, however, Cromwell makes poor decisions, which allow the ship to be captured. It is later learned that Cromwell had plans to turn the ship over because he believed it was in his own best interests.