GeoGarage Marine is a Google Map that includes a number of marine maps from different international hydrographic services.
The map includes marine chart overlays from NOAA (US), DHN (Brazil) and Linz (New Zealand). Marine GeoGarage's web interface also gives subscription members access to all private charts from the UKHO (UK), CHS (Canada), SHN (Argentina) accessible via some monthly 'Chart Premium' subscription (9.9 €/month).
GeoGarage Marine is not only a seamless chart viewer, overlaying charts at different scales on aerial and satellite imagery from Google Maps, but also allows the user to plot waypoints and to prepare navigation routes. These can be saved and uploaded to GPS (in gpx format or directly to Garmin GPS via its Communicator web plugin).
More than 3,000 marine charts are available on GeoGarage Marine and more are on the way.