# AFTER RAKE

The angle beyond vertical of the vessel's overhanging stern structure.

## Related Terms

The divergence of the air stream in a horizontal or vertical plane after it leaves the outlet.

### BUMPKIN

The spar projecting from stern of ship

### HARMONIC FUNCTION

Any real function that satisfies a certain equation. In its simplest form, as used in tide and tidal current predictions, it is a quantity that varies as the cosine of an angle that increases uniformly with time

### GREENWICH HOUR ANGLE

Angular distance west of the Greenwich celestial meridian; the arc of the celestial equator, or the angle at the celestial pole, between the upper branch of the Greenwich celestial meridian and the hour circle of a point on the celestial sphere, measured westward from the Greenwich celestial meridian throug

### GRID RHUMB LINE

A line making the same oblique angle with all grid meridians. Grid parallels and meridians may be considered special cases of the grid rhumb line.

### GRID MAGNETIC ANGLE

Angular difference in direction between grid north and magnetic north. It is measured east or west from grid north. Grid magnetic angle is sometimes called GRID VARIATION or GRIVATION.

### GYROSCOPIC DRIFT

The horizontal rotation of the spin axis of a gyroscope about the vertical axis

### HEAVE

The oscillatory vertical rise and fall, due to the entire hull being lifted by the force of the sea. Also called HEAVING

### HORIZONTAL DANGER ANGLE

The maximum or minimum angle between two points on a chart, as observed from a vessel, indicating the limit of safe approach to an off-lying danger.

### HEIGHT OF TIDE

Vertical distance from the chart sounding datum to the water surface at any stage of the tide. It is positive if the water level is higher than the chart sounding datum. The vertical distance from the chart sounding datum to a high water datum is called RISE OF TIDE.