The operator's manual that should come with every boater's GPS receiver or chart plotter.

From the National Education Officer of the U.S. Power Squadrons, here is the operator's manual that should come with every boater's GPS receiver or chart plotte

GPS For Mariners is a comprehensive guide for recreational boaters to learn how to operate and effectively use today's GPS systems in everyday navigational situ

Many books on celestial navigation take shortcuts in explaining concepts; incorrect diagrams and discussion are often used for the sake of moving the student al