There is a webinar tonight with some good content on this low cost but powerful smart phone/iPad navigation aid.
"https://navionics.zoom.us/webinar/register/56e7ed529d2174d47c24e00bf0acd2b8
Join me tonight at 7pm for a Navionics Webinar with Jessica Anderson discussing Diving South Florida Shipwrecks by clicking on the link above and registering."