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.

Apparent wind (kt)

Apparent wind speed driving the code zero sheeting angle.

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

Code zero TWA (deg)

Target true wind angle for the code zero.

• 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.

• Upwind TWA Guide

  Guide the upwind target true wind angle as forty five degrees minus half the wind speed, clamped between thirty and fifty five degrees.

• Heel Target Guide

  Guide the upwind heel angle as eight tenths of the wind speed in degrees, clamped between five and thirty degrees.

• Downwind AWA Guide

  Guide the downwind target apparent wind angle as one hundred fifty degrees plus three tenths of the wind speed, clamped between one hundred thirty five and one hundred seventy degrees.