While traditional navigation has been largely superseded by GPS, traditional navigation remains a valuable skill, an enjoyable pastime and necessary for some navigation and training courses. This handy, splash-proof, on-the-water reference guide is an aide memoire of those calculations frequently needed (but often forgotten) for traditional coastal and offshore navigation and other equations and formulae which can be useful afloat. Each topic has worked examples, and there are frequent diagrams to illustrate the process. You may be surprised by the simplicity and elegance of some of the calculations included. The book finishes by listing the main conventions used in nautical calculations and providing conversion factors which may be useful on board. Even the most dedicated GPS navigator could find this little book handy to keep on board, just in case. They may even find themselves dipping into it when they don’t actually need to.