Heading, Course, and Bearing
This post is made with the bias of a small sailboat coastal sailor. Its main purpose is a reference for me. Your nautical milage will vary.
I use a Garmin GPSMAP86 for electronic navigation on my J70 Escape. Getting caught in the fog off the coast of Santa Barbara has taught me that it is essential to have a GPS on board that is not dependent on externalities such as downloading maps as you go. Also, having a unit that allows me to set waypoints from a web page and having satellite communications is a big plus.
As a first-time user, Course and Bearing get confusing, so here are some definitions.
Heading is the direction that your bow is pointing and sailing towards. It different than course over ground (COG), which takes into consideration such as current and slippage. It is the actual
Bearing is the direction to your destination. As a sailor, it is the direction to a course mark or destination. This changes if you are not sailing towards your destination. This is important to me because it gives me a line-of-sight direction to where I want to go.
Course is good, but not too useful as a small boat sailor/racer. It is the direction of a vector or line from one waypoint to another. So, if you round a mark, it gives you the direction to your next mark. It is quite easy to get off course in open water sailing.