Agree with the other answers. Except that I think most compass deviation cards would show a value for 045 degrees, which would be even more relevant in this example than the 090 degrees which tacpot mentioned - the desired Hdg(M) would then be roughly half way between two headings on the deviation card, so you should average the two deviation readings.. .. .Although, to tell the truth, it's so long since I've looked at a compass deviation card, I might be talking crap!. .. .FFF. .-----------. . . . <small>[ 21 March 2002, 10:01: Message edited by: FlyingForFun ]</small>