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.

Sail area (m²)

Gennaker area projected to the wind.

Wind speed (m/s)

True wind speed at sail height.

Estimate the tack line load of a gennaker using tackLoadNewtons = 0.06 * windSpeedMs^2 * sailAreaM2 with a documented gennaker load 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]

Tack load (N)

Tensile load on the gennaker tack line.

• 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.

• Mooring Windage Load Calculator

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

• Sail Drag Force Calculator

  Compute aerodynamic sail force from forceNewtons = 0.5 * 1.225 * windSpeedMs^2 * sailAreaM2 * dragCoefficient.

• Post-Tack Acceleration Time

  Estimate how long a boat needs to recover full speed after a tack from the speed deficit and the acceleration rate.