From Polar Navy:
PolarView NS is a complete user friendly on-board marine navigation system. It is available for Apple Mac OS X, Microsoft Windows and Linux operating systems. PolarView NS combines free marine chart planning, tides and weather with live GPS navigation and AIS capabilities. It supports ENC charts in S57 format (available from NOAA), raster charts in BSB format, as well as world wide standard S63 vector charts. PolarView includes Tides and Currents display, using the industry-standard TCD tide database format. PolarView is a fully-featured GRIB weather viewer supporting wind, isobaric pressure, wave contours, temperature. PolarView includes a free built-in GRIB download service with GRIB data based on NOAA NCEP GFS and NWW3 models. World basemap is included. Routes and waypoints can be edited directly on the chart and imported/exported to GPX and CSV files.