High variations near west africa

Archie2009
12th February 2012, 22:54
Hi,
The magnetic compass of our vessel was created after a compass swing post refit in Spain(max deviation after corrections 1 degree) Every time the vessel crosses the magnetic equator on her way south to west Africa, the deviations are way off, unto 15 degrees at times. Any way to correct this other than making a new deviation card when the ship is around the magnetic equator.