To quickly determine a ship's total weight (displacement) at a given water level (draft), which specialized chart would you use?

To quickly determine a ship's total weight, known as its displacement, at a given water level, which is called the draft, you would use a ship's hydrostatic curves. Hydrostatic curves are a specialized chart, or set of graphs, that are unique to each individual vessel and graphically represent various hydrostatic properties of the ship plotted against its draft. To find the displacement, one would first locate the ship's current draft on the vertical axis of the hydrostatic curve chart. Then, by following this draft horizontally to intersect the specific displacement curve, and subsequently moving vertically or horizontally to the appropriate scale, the ship's total displacement can be read directly. Alternatively, some ships may be equipped with a displacement table, which is a tabular listing of the same data, allowing for a direct lookup of the ship's displacement corresponding to a given draft. Displacement refers to the total weight of the ship, including all its cargo, fuel, stores, and personnel, and it is numerically equal to the weight of the water that the ship displaces. Draft is defined as the vertical distance from the waterline, which is the surface of the water touching the ship's hull, to the lowest point of the ship's hull. The displacement values provided on hydrostatic curves or in displacement tables are typically calculated for a standard water density, such as that of saltwater, and a correction may be necessary if the ship is operating in water of a different density.