The OpenSeaMap project aims to create free nautical charts through a wiki-based map creation process based on the OpenStreetMap approach, and using the OpenStreetMap database. The goal is to record interesting and useful nautical information for the sailor such as beacons, buoys and other navigation aids as well as port information and repair shops. Similar to the start of OpenStreetMap, the efforts are getting their start in Europe, with nautical charts for the Baltic Sea and North Sea first to come online.
There’s a good overview of the project, including the unique challenges, in this story from Wired.
