Harry Collingwood was the pseudonym of William Joseph Cosens Lancaster who went to sea at 15 but had to abandon his naval career due to severe myopia. He went on to write 23 nautically based novels, of which this, first published in 1895, tells the story of a young midshipman's adventures on a British warship patrolling the waters off the west coast of Africa in a bid to prevent slave traders heading for Cuba.