Marine & Navigation

Anchor Scope & Holding Calculator

Check required scope and estimate holding confidence for anchoring setup.

Last validated: 2026-02-14

Anchor Scope & Holding Calculator checks whether deployed rode meets scope requirement and estimates a holding confidence score from scope, wind, and bottom type. It is useful for quick anchorage setup review when selecting rode length and judging relative holding robustness. The score is a planning heuristic, not a certified holding-force calculation. Use it to support anchoring decisions and combine with local seamanship practice and watchkeeping.

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Input Pattern

Enter values in the left panel, keep units explicit, run the calculation, then copy or share the result. Invalid fields are highlighted immediately.

Anchor Inputs

Result

Required rode: 50.00 m

Rode margin: 5.00 m

Recommended scope for wind: 7.0:1

Scope requirement met: Yes

Holding score: 45.2/100

How to use this tool

Enter depth, bow roller height, desired scope ratio, and deployed rode length.
Add wind speed and select seabed type, then run assessment.
Confirm scope requirement status and review holding score before final anchor setup.

Worked Example

Auto-generated from the tool's current default or entered inputs.

Example Inputs

Depth m: 8.0
Bow roller height m: 2.0
Scope ratio: 5.0
Deployed rode m: 55.0
Wind kn: 22.0
Bottom type: sand
Required rode m: 50.0
Rode margin m: 5.0

Expected Outputs

Depth m: 8
Bow roller height m: 2
Scope ratio: 5
Deployed rode m: 55

Interpretation

Depth m is 8.0. Use this as a decision input, not as a standalone conclusion.
Bow roller height m is 2.0. Use this as a decision input, not as a standalone conclusion.
Scope ratio is 5.0. Use this as a decision input, not as a standalone conclusion.
Cross-check the result against one alternate input set to validate sensitivity.

Scenario Compare (A vs B)

Use this to compare two input sets and quantify change in key outputs.

Scenario A

Depth m

Bow roller height m

Scope ratio

Deployed rode m

Wind kn

Bottom type

Required rode m

Rode margin m

Scenario B

Depth m

Bow roller height m

Scope ratio

Deployed rode m

Wind kn

Bottom type

Required rode m

Rode margin m

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Anchor Scope & Holding Calculator

Input Pattern

Anchor Inputs

Result

How to use this tool

Worked Example

Example Inputs

Expected Outputs

Interpretation

Scenario Compare (A vs B)

Scenario A

Scenario B

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