GMDSS (Global Maritime Distress and Safety System) and VHF (Very High Frequency) radiotelephone are integral components of the worldwide marine radio communications system. Nearly six million U. S. and Canadian recreational sail- and powerboats carry VHF radios. Endorsed by the U. S. Coast Guard and written by a navigation VHF-DSC radio trainer, this userfriendly guide gets boaters quickly up to speed on both analog and digital VHF radiotelephone usage. Its straightforward, nontechnical coverage, "Geek-speak" boxed definitions, quick reference chart, and more make it easy for readers to quickly master and get the most out of their radios.