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A correction method for shallow-water effects on ship speed trials

Aug 5, 2022
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In 2021, the International Towing Tank Conference accepted a new procedure to correct ship speed trial results for the limited effects of shallow water, the so-called ‘Raven shallow water correction’. This method is also included in the 2022/2023 revision of the ISO15016 “Guidelines for the assessment of speed and power performance by analysis of speed trial data”. It thus replaces Lackenby’s formula, which had been used until now.

The new procedure has been derived from physical modelling and extensive computational work at MARIN. For most validation cases, which mainly result from full-scale trials in several water depths, it gives a much better estimate of the true water depth effects on the speed achieved.

A report has now been published that collects the main information from several previous papers by the same author; adds new checks and comparisons; and discusses all the validations done and that could be found in the literature. The background, limitations and possible refinements of the method are also reviewed.

The new report is freely downloadable: H.C. Raven, ‘A correction method for shallow-water effects on ship speed trials’, Report 98800-1-RD, MARIN, June 2022