Weight estimate

A weight estimate is the engineering rollup of a ship’s mass and its center of gravity, summed from the structural, machinery, and outfit weight groups plus margins. It produces the lightship weight and its LCG, VCG, and TCG, which set the displacement available for deadweight and feed every stability and trim calculation. Early in design the groups come from parametric formulas and database ratios against length, beam, and depth; by detail design they are built bottom-up from plate takeoffs and equipment lists. A weight and KG margin is carried through construction, and the estimate is closed out by the inclining experiment, which measures the as-built lightship displacement and KG to confirm or correct the estimate.