TURNING WITH A CONSTANT RADIUS IN BUILDER'S SPEED-TRAILS

The Authors, of AG Weser and the Hochschule fur Nautik (Bremen) respectively, describe how AG Weser's measured-mile trials of the two 53,000-ton (gross) container-ships Table Bay and City of Durban were run in Boknfjord. A procedure was employed in which the ship followed a course of constant radius when turning at each end of the several speed-measurement runs, thereby avoiding excessive use of the helm, minimising the loss of speed when changing course, and saving time. The procedure for the two ships differed in some respects because City of Durban was equipped with a rate-of-turn indicator for her trials in Jan. 1978, whereas Table Bay, which ran trials in Sept. 1977, was not so equipped. It is mentioned that the constant-radius turning procedure appears to be unnecessary for ships with a gross tonnage below about 20,000. Order from BSRA as No. 49,506.