Device for reading directly from a chart the heading to be followed by an air or sea-going vehicle

A device for directly reading from a chart the heading to be followed by an air or sea-going vehicle, comprising a disk having at its periphery a rotatable circular coaxial graduation of the "compass card" type rotatable with respect to the disk so as to be able to be oriented with respect to the North, this disk being itself mounted for rotation about a fixed shaft integral with a support, through a rotary fitting with offset adjustable in modulus as a function of a value representative of the wind or current speed/proper speed of the vehicle ratio and in orientation along the direction of the wind or of the current, said disk further comprising at least one scale for determining the modulus of the offset, as well as a first reference mark for indicating the orientation of this offset on the circular graduation, said scale being graduated in successive values representative of said wind or current speed/proper speed of the vehicle ratio, the heading to be followed being indicated on the circular graduation by a straight line oriented along the geographical heading or course and passing through said axis, wherein said support comprises a rectilinear edge adapted for alignment with a geographical heading plotted on the chart, an axis (VS) parallel to said edge and passing through said fixed shaft, and means for reading the flight or navigation time as a function of a distance between two points on the chart, the proper speed of the vehicle, the scale of the chart and a correction ratio of the flight or navigation time, said axis forming with an edge of said disk an intersection point having a position which determines said correction ratio.