I'm guessing that incorporating ENC charts would be a lot of work on the part of the maemo mapper developer because they are vector-based, not raster based. That is, the ENC chart is really just a very complicated list of coordinates. AFAIK, the maps that maemo mapper currently support are all basically regular images with positioning information included to tell you how to piece them together.

To support ENC charts, mapper would have to parse out the file and actually draw everything on the screen. I'm a programmer with a software company that sells hydrographic survey and dredge software so I've wrangled with ENC charts--not a heck of a lot of fun...

A more likely solution would be conversion of ENC charts to pngs at various resolutions in the directory structure mapper supports.

would be cool though.