A correction method for shallow-water effects on ship speed trials
Aug 5, 2022
In 2021, the International Towing Tank Conference accepted a new procedure to correct ship speed trial results for limited effects of shallow water, under the name ‘Raven shallow water correction’. This method is also included in the 2022/2023 revision of ISO15016 “Guidelines for the assessment of speed and power performance by analysis of speed trial data”. It thus replaces Lackenby’s formula, which was used so far.
The new procedure has been derived from physical modelling and extensive computational work at MARIN. For most validation cases, mainly from full-scale trials in several water depths, it has been found to give 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 validations done and that could be found in the literature. The background, limitations and possible refinements of the method are also reviewed.