Are available at:
http://nauticalcharts.noaa.gov/staff/charts.htm
If you have these charts aboard, you will be considered in compliance
with USCG regulations and the NOAA electronic charts are now considered
fully compliant with SOLAS standards.
(I need to research whether having the charts available as an
electronic file, only, without a printed copy generated from the file
qualifies. I know the commercial ships now print their own "official"
charts as they approach a region, so this leads me to believe these may
have to be printed out to be in compliance. Anybody know for an
absolute fact?)
Value-added providers, (firms that take these charts, add additional or
peripheral information, and then repackage them for resale) will need
to conform to a set of NOAA-specified practices for the raster charts
to maintain their "official" status.