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.

Ballast weight (lb)

Weight of the ballast keel.

Displacement (lb)

Total displacement of the vessel.

Compute a sailboat's ballast ratio using ballastRatioPercent = ballastWeightPounds / displacementPounds * 100. 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]

Ballast ratio (%)

Ballast weight as a percentage of displacement.

• 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.

• Wave Making Resistance Ratio

  Compute the wave making share of total hull resistance using wavemakingRatioPercent = waveResistanceNewtons / totalResistanceNewtons * 100.

• Anchor Rode Length Calculator

  Compute the anchor rode length needed from water depth, freeboard, and scope ratio.

• Anchor Scope Ratio Calculator

  Compute the scope ratio from the deployed rode length and the total height to the bow chock.