Course Correction Calculator

Tide charts, current charts and calculations are useful as a starting point in navigation but actual currents are hard to predict. To maintain the proper heading, frequent changes in the direction of the course steered is to be expected. Go To Tidal Height Page

The following three steps are used to determine the Course to Steer in order to maintain a desired heading or track. This calculation is often done by hand or can be computed by a calculator (button link to the right):

	First, draw a line to represent the desired course or heading. This line is called the "track" or the "course to make good".
	Next, draw a line representing the current vector whose length is proportional to the speed of the current and angle corresponds to the direction of the current.
	Finally, draw a line representing the power vector of the sailboat, the length of the line is proportional to the speed of the craft on the water (as determined by the tachometer or knotmeter- The instrument on a sailboat which measures distance and is used to compute speed is called a "log" ). This line is drawn between the end of the current vector and the line representing your track. The speed of the Course to Make Good is called the Speed of Advance.

The power vector now represents the Course to Steer by and the Course to Make Good corresponds to the desired heading or track. Remember, if you cannot determine an accurate course, keep the heading up current or upwind from you destination. This will allow you an easy approach in case of an error, otherwise you may be sailing up current or against the wind.

Another correction of the Course to Steer, is to account for leeway or a sideway's drift of your craft. Leeway is most pronounced in a high wind and of a close-hauled point-of-sail. In medium size sailboats, 30', leeway may account for as much as a 10 degree course deviation. The Course to Steer adjusted for leeway is called the Course Made Good Through Water.

On a navigational chart, the above track or Course to Make good would be identified using lines and plotting symbols. These symbols are beyond the scope to this course but are described in a number of manuals on coastal navigation. An excellent one is available through US SAILING.

Track: The desired heading or the Course to Make Good.

The Course to Steer: The direction you must steer the boat to stay on Track.

Course Made Good: The direction the boat actually traveled.

Speed Made Good: The speed the boat actually traveled (Speed of Advance).