Running Surface

The running surface is the part of a boat’s hull that actually supports and contacts the water while underway. On a planing powerboat it is mainly the after, flatter sections of the bottom, including chines, strakes and any wetted area near the transom. On displacement craft, the effective running surface is the immersed hull shape moving through the water.

Its shape and condition directly affect speed, grip, trim, stability and Fuel Consumption. A clean, fair running surface reduces drag, while damage, fouling or poor weight distribution can cause porpoising, chine walking, slamming or loss of control in rough Sea State. It is closely related to Hull design and how the boat transitions onto the plane.

For passage planning, expected wind, waves and load help determine whether the running surface will operate efficiently or be overpowered. PredictWind wave forecasts and Power Routing can help power boaters choose speeds and routes that suit the hull form and reduce uncomfortable impacts.