This the only ENC displayer on the Mac platform as of now. I'm very thankful that it exists. ENC charts are nautical chart database made available for free to the public by NOAA. These databases are the basis of vector charts that's becoming increasing popular (as oppose to raster charts). There are many PC nautical charting softwares but precious few for Mac, let alone one that can display ENC files. There is much room for improvement but it's a very good initial effort.

The sample chart included is for a very small region, you can go to noaa's website: http://chartmaker.noaa.gov and download ALL the charts for every major U.S. port (~300 MB). The demo version happily reads them in.

I'd give 5 stars for this unique and very useful program, but the performance is a little too slow on my iBook G4 (800 MHz), so I have to give it 4 stars.