Comprehensive information. NAVIGATION: GPS, LORANC, RDF, radar, depth sounder. COMMUNICATIONS: VHF, SSB, CB, EPIRB, HAM. Includes procedures, rules, tips, and problem solving. Marine electronics are vital to the safety and enjoyment of your boat. This card removes any confusion about the proper use of the electronics. Concisely written and easy to understand. - Clyde Kirlin, marine electronics consultant.