Definition
Measured westward from the Greenwich meridian from 0 to 360 degrees, GHA is tabulated hourly in the almanac and interpolated with the increments and corrections pages using minutes and seconds of GMT. For stars, GHA is found by adding the Sidereal Hour Angle of the star to the GHA of Aries. Local Hour Angle is GHA minus west longitude or plus east longitude, again normalised into the range 0 to 360 degrees.
Want to apply this on the water?
Ask Saily out loud for an example, a scenario or a simpler explanation.
Talk to Saily