En fait, non, tu ne fais pas de confusion... Il me semble que SeaMap est la version dédiée android pour Smartphones, si j’en crois leur documentation ci dessous :
Description
SeaMap shows nautical information on a map. This includes beacons, buoys and other navigation aids. This information is obtained from OpenSeaMap which is part of the OpenStreetMap project. It mainly covers parts in Europe, like the Baltic Sea and the North Sea. But more regions are covered like for example areas in Australia.

Michel