Robert Michael Ballantyne 
Martin Rattler (Annotated) [EPUB ebook] 

Mischievous young Martin Rattler is desperate for a life at sea. When he finds himself on board the 'Firefly' he can’t quite believe his luck, and soon falls in with young Barney O’Flannagan. There is trouble ahead however, and when the 'Firefly' is attacked by pirates the pair must make a hasty escape. They wash up in the Amazon, where they discover new plants and animals, meet new people, and have plenty of daring adventures together. A swashbuckling tale from much-loved author R.M. Ballantyne.