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.

Boom attachment distance (m)

Distance along the boom from the mast to the vang attachment.

Mast attachment height (m)

Height on the mast where the vang attaches above the boom.

Compute the vang angle in degrees as atan of the mast attachment height over the boom attachment distance. 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]

Vang angle (deg)

Angle between the vang and the boom.

• 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.

• Spinnaker Pole Height

  Compute how high the outboard tip of a spinnaker pole sits above the mast attachment using pole length times the sine of the elevation angle.

• Mast Rake Calculator

  Compute mast rake from the horizontal masthead offset and the vertical distance between the masthead and the lower measurement point.

• Rudder Correction Angle Calculator

  Compute the rudder correction angle from correctionDeg = degrees(atan(lateralDriftMs / forwardSpeedMs)).