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.

True wind from (°)

Direction the true wind blows from.

Layline side

Side of the wind for the opposite tack layline.

Close-hauled angle (°)

Angle between the boat's close-hauled course and the true-wind direction; the full tacking angle is twice this value.

Calculate the bearing of the opposite tack layline by offsetting the true wind direction by the tacking angle to the chosen side of the wind. 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]

Opposite layline bearing (°)

Bearing of the opposite tack layline.

• 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.

• Opposite Tack Course Calculator

  Calculate the corresponding course on the opposite tack by reflecting the current course across the true-wind direction.

• Tacking Angle Calculator

  Calculate the tacking angle using tackingAngle = 2 * closeHauledAngleDeg from the close-hauled angle off the wind.

• Anderson Turn Course

  Calculate the return course reached by an Anderson turn, which rotates the heading two hundred forty degrees toward the chosen turn direction to bring the vessel back along its original track.