This practical manual is based on the graphical approach which encourages the solution of navigational problems by drawing lines on a chart - the method which is considered best suited to yachts because, unlike the alternative mathematical method, most of the errors that can be made are apparent to anyone with common sense. The book is published primarily in response to a demand from people studying the Yachtmaster Offshore Certificate syllabus, for a manual that eliminates all traces of excessive theory which can be confusing to beginners.