Navigation aid

Claim 2

A navigation aid for determining the magnetic compass heading to reach a destination from a departure point comprising, a base having a surface, means defining an axis of rotation extending from substantially the center of the surface perpendicular thereto, a chart about said axis of rotation and rotatable with respect to the surface, a compass rose concentric with said axis and rotatable thereon with respect to the surface, an index on the surface for the compass rose, a magnetic variation index on the chart and a magnetic variation scale on the compass rose, and means providing course lines overlaying the chart, whereby the chart and compass rose are independently rotatable on the axis, the index on the chart aligning with a reading of the scale to account for magnetic variation when and a course line is in registration with the departure and destination points on the chart, so that the index on the surface designates the magnetic compass heading on the compass rose to reach the destination from the departure point.

Claim 3

A navigation aid as in claim 1 wherein, the overlay with course lines is a transparent sheet attached to the surface along one edge of the sheet and pivotal about said edge.

Claim 4

A navigation aid as in claim 1 wherein, the overlay of course lines slides along a track along one edge of the surface.

Claim 5

A navigation aid as in claim 1 wherein, a holder is provided for the chart and the index on the chart is fixed to the holder.

Claim 6

A navigation aid as in claim 4 wherein, the chart is mounted to the holder and the holder is rotatable on the axis thereby rotating the chart on the axis.

Claim 7

A navigation aid as in claim 5 wherein, the compass rose is between the chart holder and the surface, a magnetic variation scale is included inside the compass rose, and the magnetic variation index on the holder is adjacent said scale.

Claim 8

A navigation aid as in claim 6 wherein, the aid is so constructed that, the holder is positioned on the compass rose with the magnetic variation index at the magnetic variation on the scale, which is the magnetic variation for the chart in the holder, and then the compass rose and holder are rotated on the axis together to place a course line from the overlay coincident with destination and departure points on the chart, whereby the index on the surface indicates the magnetic compass heading on the compass rose for a course from the departure point to the destination point.

Claim 9

A navigation aid for determining the magnetic compass heading to reach a destination point from a departure point comprising, a rotatable flat piece containing on one surface thereof a chart and a compass rose in fixed relationships to each other, the compass rose defining a rotation axis transverse to the surface of the piece, the chart being oriented with the north magnetic variation line thereof aligned with north on the compass rose, a transparent flat piece overlaying the rotatable piece surface and having parallel course lines stationary thereon, means for holding the rotatable piece adjacent and parallel the overlay so that the course lines are superimposed on the chart and the rotatable piece is rotatable on said axis relative to the overlay, and an index on the overlay for the compass rose, whereby, upon rotating the rotatable piece to place the same course line over both a departure and a destination point on the chart, the magnetic compass heading for the course from said departure to destination is indicated by the index on the compass rose.

Claim 10

A navigation aid for determining the magnetic compass heading to reach a destination point from a departure point comprising, a rotatable flat piece containing on one surface thereof a chart and a compass rose in fixed relationships to each other, the compass rose defining a rotation axis transverse to the surface of the piece, the chart being oriented with the north magnetic variation line thereof aligned with north on the compass rose, a transparent flat piece overlaying the rotatable piece surface and having parallel course lines stationary thereon, means for holding the rotatable piece adjacent and parallel the overlay so that the course lines are superimposed on the chart and the rotatable piece is rotatable on said axis relative to the overlay, and an index on the overlay for the compass rose, whereby, upon rotating the rotatable piece to place the same course line over both a departure and a destination point on the chart, the magnetic compass heading for the course from said departure to destination is indicated by the index on the compass rose.

Claim 11

A navigation aid as in claim 8 wherein, the course line overlay is one side of an envelope into which said rotatable flat piece of compass rose and chart is inserted and rotatably positioned therein on said axis, and the index which designates compass heading on the compass rose may be on the overlay or the other side of the envelope.