A real-time ship simulation investigation of the proposed designs for deepening and narrowing the navigation channel for Grand Haven Harbor, Michigan, was conducted. The purpose of the study was to determine if the navigation channel could be deepened from 21 to 27 ft and narrowed from the existing 300 ft to 225 ft and maintain adequate safety. A numerical model of the existing channel from Lake Michigan to the supper limit of the maintained channel was developed. The numerically generated currents were validated independently by two test pilots from the study area since no recorded current velocities exist. They independently reached the same conclusion that the currents should be approximately 1.1 mph. The pilots tested the existing 300-ft channel and two different 225-ft channel proposals. Testing was performed on the U.S. Army Engineer Waterways Experiment Station Ship simulator. These tests demonstrated that either of the 225-ft channel proposals would be acceptable at a 27-ft depth the channel through the jetties should be centered between the jetties, and range markers should be provided.