Block coefficient verification (sea trial)

Block-coefficient verification on a sea trial confirms the as-built fullness of the hull from the trial draft survey, comparing the measured displacement at the surveyed drafts against the value the block coefficient Cb predicts for that waterline. Cb equals the displaced volume divided by the box L x B x T, so a draft survey at trial gives an independent check on the lines and the loading-computer hydrostatics. A divergence flags either a draft-reading error, a trim effect, or a deviation between the as-built hull and the design offsets, all of which propagate into the speed/power analysis through the displacement term.