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.

Depth (ft)

Water depth at anchor.

Freeboard (ft)

Height of the bow chock above the water.

Rode length (ft)

Length of rode deployed.

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

Scope ratio

Ratio of rode length to depth plus freeboard; seven is standard for overnight.

• 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.

• Anchor Circle Radius Calculator

  Estimate the maximum anchor-to-bow radius from water depth and rode scope. Add the vessel length when checking the full area swept by the stern.

• Anchor Rode Length Calculator

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

• Comfort Ratio Calculator

  Compute Ted Brewer's motion-comfort ratio from displacement, waterline length, and length overall. When LOA is omitted, it is assumed equal to LWL.