Abstractthis paper containsa description of the Norden marine course computer and its sea evaluation aboard the S. S. Pioneer Ming. The computer provides a course control signal to a gyropilot as it estimates position and performs a number of other computations. It was designed to be a building block for partially automated ships and has been specified for AGS type ships. The device was successfully tested and found to be a reliable, accurate navigational aid. A standard error of only 4.5 miles results 12 hours after position fix—after 36 hours the error will be 7.8 mile