Advances in technology have made the ability to cross oceans safely within reach of more mariners than ever. GPS chart plotters can keep you within yards of your intended course. Until they fail. Not just your equipment, but the entire GPS network. Which happens with more regularity every year. Then what? What you will learn from this course and an inexpensive Mark 3 sextant will give you the skills to find your way home or to your next port.

Boater U’s “Celestial as a back up to GPS” course provides a means of learning and executing a position fix at sea when a vessel has lost its GPS navigation. Using the inexpensive plastic Davis Mark III sextant and David Burch’s text on it’s use, mariners will have a solution that is compact and inexpensive, using tables and procedures that are easy to learn and use.