




18° 61,23' N  061° 13,76'W. Are these coordinates plausible ? 











With the Mercator projection 











When using Mercator projection one measures distances on 











The unit used at sea for distances is the Nautical Mile which represents 











A variation of 5°W is indicated on the navigational chart. The helmsman affirms he is following a 135° course. What do I trace on the chart ? 











After having calculated a course of 180° I want to give indications to the helmsman. The variation in the area is 10°W. What do I tell the helmsman ? 











The variation of the area is to be found 











The height of the water in the harbour is 5,5m. How much water will I have on a sounding of 2,5 underligned ? 











When taking a compass bearing I will have to take into account 











All the points on the same Latitude form the 








