Powder Monkey: The Adventures of Sam Witchall by Paul Dowswell
Sam is desperate to leave his sleepy Norfolk village and see the world. He seizes the chance to join a merchant ship, but soon discovers that a life at sea is harsh and often short, especially when his ship is attacked by a French privateer. About to be boarded, they fear all is lost, but the privateers are driven off by the appearance of a Royal Navy ship. Sam's relief is short-lived. Soon after, another Navy ship sends over a press gang, and he is forced to join the frigate Miranda. War with France and Spain is raging and Sam is caught in the middle with a dangerous job as a powder monkey in the company of a brutal crew. This is an amazingly well-researched adventure giving a glimpse of one boy's incredible life at sea.