Displacement

Displacement is the weight of seawater a vessel pushes aside when floating, which is equal to the vessel’s actual weight in that condition. It is usually stated in tonnes and changes with fuel, water, crew, stores and cargo. A displacement hull relies primarily on buoyancy rather than planing lift, so it moves through the water instead of skimming over it.

For boaters, displacement affects stability, motion, speed potential, fuel use and safe loading. Adding weight increases Draft, lowers Freeboard and changes the Waterline, which can influence shallow-water clearance, comfort in a seaway, and compliance with loading limits.

In passage planning, an accurate displacement helps estimate realistic boat speed and power requirements. PredictWind Weather Routing, Power Routing and AI Polar can produce better results when vessel settings reflect the boat’s loaded cruising condition, not an empty brochure weight.