Use this sailing calculation for planning or education when the vessel, units, reference directions, environmental conditions, and assumptions are explicitly known.

Close-hauled angle (deg)

Required number in deg. Close-hauled angle off the wind, between 10 and 80 degrees.

The cited overview of Sailing supplies background for the terminology and domain context used by this tool.^[1]

Calculate the tacking angle using tackingAngle = 2 * closeHauledAngleDeg from the close-hauled angle off the wind. Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.

Tacking angle (deg)

Returned number in deg. Total angle between the two tacks.

• Vessel design and loading, sea state, wind, current, tide datum, weather, chart accuracy, equipment, crew, and safety margins can make real conditions differ from a simplified result.
• Close-hauled angle must be at least 10.
• Close-hauled angle must be no greater than 80.
• Use finite inputs in the displayed units, preserve source measurements and assumptions, and independently verify consequential decisions.

Cross-check current charts, tide and weather services, instrument data, vessel manuals, and applicable navigation rules, and retain a conservative alternative plan.

• Opposite Tack Layline Bearing

  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.

• Code Zero Wind Angle

  Estimate the true wind angle for a code zero using codeZeroTwaDeg = round(50 + apparentWindKt * 0.3), clamped to 40 through 70 degrees.

• Reefing Wind Speed Calculator

  Calculate the apparent wind speed at which to reef using reefWindKt = designWindKt * reefFactorPercent / 100.