Which ship characteristics are considered in preliminary design calculations?

In the preliminary design stage of naval architecture, the primary objective is to develop a feasible and economical vessel that meets specific owner requirements, such as cargo capacity, speed, and cruising range. To achieve this, naval architects perform calculations based on several key ship characteristics:1

• Principal Dimensions: The designer selects initial values for the ship's length, breadth, depth, and draft.12
• Displacement and Weight: The total displacement must equal the sum of the deadweight (cargo, fuel, and stores) and the lightship weight (hull, machinery, and equipment).32
• Hull Form: Architects determine hull coefficients to define the shape, which must be appropriate for the intended speed and stability requirements.12
• Powering: Calculations are made to estimate the shaft horsepower required to achieve the specified trial and sea speeds.12
• Strength and Scantlings: Preliminary longitudinal strength calculations are used to determine the necessary scantlings, which dictate the weight of the hull steel.12
• Stability and Trim: Designers ensure the centre of gravity is positioned to provide satisfactory trim and stability, often checking these against international regulations.42