[shiandow]

OsmAnd has a nautical map plugin you can enable.

[jboss10]

The plugin is just part of why OsmAnd is good for nautical use, there is also an alternate view in the configure map menu for nautical use.

[RobotToaster]

For some reason osmAnd was the only GPS map that would work on a flight for me.

[ihatehn]

OM and CoMaps should also work, though you might need to wait awhile for a GPS fix and be near a window. Google's main hiccup will be an internet connection for the maps.