Use this sailing calculation as a planning or educational cross-check for navigation, wind and current, rig loads, stability, anchoring, tides, visibility, performance, or recovery under explicitly stated conditions.

Boat speed (m/s)

Boat speed through the water.

Keel area (m²)

Projected keel area.

Lift coefficient

Section lift coefficient between zero and two.

Compute the hydrodynamic lift generated by a keel from boat speed, keel area, and a lift coefficient. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Keel lift (N)

Hydrodynamic lift force on the keel.

• Actual conditions change with vessel design and loading, sea state, wind, current, tide datum, weather, chart accuracy, equipment, crew, regulations, and safety margins. Simplified formulas do not replace seamanship, approved stability data, or current navigation information.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Cross-check official charts, tide and weather services, instrument data, vessel manuals, and collision regulations; maintain conservative margins and a safe alternative plan.

• Wind Pressure on Sail Calculator

  Compute aerodynamic force on a sail from dynamic pressure using 0.5 times air density times wind speed squared times sail area times lift coefficient.

• Leeway Angle Calculator

  Estimate leeway angle with the empirical relation leeway = K times heel divided by boat speed squared. Calibrate K for the hull, keel, and knot-based speed data in use.

• Mooring Windage Load Calculator

  Compute the wind load on a moored vessel from wind speed, windage area, and drag coefficient.