A simple explanation would be great. I am reading a manual for digital compass and there is a paragraph with the following words:
The SpeedPuck automatically detects when a sailor is trimmed to a heading then provides the header/lift indication. When the device detects that the sailor is trimmed at a heading the trim angle is set. Then header/lift indication is given off of that trim angle. Once a tack or a jibe is detected the indicator resets and nothing is indicated until another trim angle is set. Each bar segment represents 3 degrees of wind shift.
I don't really understand what header/lift indication is. If only someone could explain plain simple words, that would be great!