Aids to Navigation Principal Findings Report: The Effect of One-Side Channel Markings and Related Conditions on Piloting Performance.

Abstract : This experiment is one of a series done to quantify the relationship between variables related to aids to navigation and piloting performance in narrow channels and, potentially, safety in such channels. This is one of several experiments restricted to visual piloting, and further to buoys only. It was performed on a simulator built for the U.S. Coast Guard. The variable conditions evaluated were: (1) Straight channel markings (buoy configurations were: gated, on one-side inside relative to the turn, on one-side outside relative to the turn, and staggered); (2) Turnmarkings (two-buoy and three-buoy turns); (3) Buoy height above the water (10-foot and 17-foot buoys); (4) Spacing (buoys spaced at 5/8 nm and 1-1/4 nm); and (5) Visibility (at 3/4 nm and 1-1/2 nm). The constant conditions were a 500-foot wide channel with a 35-degree noncutoff turn run during the day with wind and current varying over the scenario. The ship was a 30,000 dwt tanker with the bridge 75 feet forward from the center of gravity, and pilots were instructed to keep transit speed at 6 knots. The findings of the experiment are presented as the means and standard deviations of crosstrack position of transits under each condition. These are interpreted in terms of their implications for the design of channel markings.