Usage Instructions: it is highly recommended to download nautical basemap in order to see the maps regardless of detailed map presence. Nautical charts are provided as a map and a special style, to switch style in OsmAnd please use the menu item 'Configure Map' on the map screen.
Nautical Chart is a detailed graphical representation of oceans, seas, coastal areas and rivers.
Nautical Charts are made for people who drive any kind of vehicle on water: from professional sailors to people who rented a boat to make a tour over city canals. The charts can contain various information like sailing routes, navigation lights, dangerous areas, areas where it's allowed or not allowed to sail or dock, etc.
All the professional sailors are obliged to have official nautical charts on their ships. These charts are published by authorized agencies and cost quite some money. Agencies are investing a lot in keeping the charts up to date. They release updates for the charts on regular basis, but because of the fact that reviewing the information and processing the updates takes quite some time the nautical charts are never completely up-to-date.
Nautical charts of OsmAnd are based on the data from OpenSeaMap project. The idea of the project is to build the detailed map by people how actually use it. Every user of the map can contribute by adding changes to it making it more detailed and more accurate.
While OpenSeaMap charts at the moment cannot compete with official nautical charts, they can be used by recreational sailors for orientation or route planning.