AIDS TO NAVIGATION PRINCIPAL FINDINGS REPORT: RANGE LIGHT CHARACTERISTICS AND THEIR EFFECT ON PERFORMANCE

The experiment described here is one of a series done for the U.S. Coast Guard 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 was performed on a simulator built for the U.S. Coast Guard at Eclectech Associates in North Stonington, Connecticut. The variable conditions evaluated were: (1) sensitivity ranges (high lateral sensitivity at K is approximately 4.5 or low lateral sensitivity at K approximately 0.5), (2) designated track (with the objective to stay either on the centerline or on the right quarterline), and (3) angle of turn (15-degree or 35-degree noncutoff turn). The constant conditions were a 500-foot channel with two 1.3 nm straight legs joined by a bend. Each straight leg has a range light marking the centerline of the legs and these were the only aids available. The scenarios were run at night with wind and current varying through the transit. 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 nots. 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. (Author)