No registration. No downloads. Right from web page. Any exercise area across the world. Real terrain.
Recent Firefox, Chrome, IE, Opera are OK. For Opera, enable WebGL in opera://flags. Safari only from Linux. Same style GMDSS and navigation signs simulators are possible. Your comments and bug reports are very welcome.
Correction of SRTM HGT files to account for seabed depths and accurate waterbody lines. Download of
generated CAD STL files for modified Earth terrain geometry. Any area of 1 square degree within 60°S and 60°N of latitude range.