Anchor Rode Length Calculator
Calculate the recommended anchor rode (scope) for safe holding based on water depth, freeboard, and sea conditions.
Results
What is it?
Anchor scope is the ratio of anchor rode (chain + rope) paid out to the total vertical distance from bow roller to seabed. A higher scope keeps the anchor chain more horizontal, which improves holding dramatically. Scope 5:1 is acceptable in calm weather; 7:1 is the cruising standard; 10:1 or more in heavy weather.
How to use
1. Enter the water depth at your anchoring spot in feet. 2. Enter your bow freeboard (height of your bow roller above the waterline) in feet. 3. Select your conditions to get the recommended scope. 4. The calculator shows how much rode to deploy for each scenario.
Example scenario
Anchoring in 15 ft of water with a 4 ft freeboard. Total depth = 19 ft. At normal scope (7:1): 19 x 7 = 133 ft of rode. At storm scope (10:1): 190 ft. Always allow extra chain to pay out if conditions deteriorate overnight.
Pro tip
All-chain rode requires less scope than rope because the chain weight creates a catenary curve that absorbs shock loads. With all-chain, 4:1 scope in calm weather is often sufficient. Rope-and-chain combinations need closer to 7:1. Add a snubber to reduce shock loading on the windlass in any conditions.