Anchor Scope Explained
Why scope ratio matters for holding and how much rode to use.
Author: OceanCalc Editorial Team · Publisher: Albor Digital LLC
Scope is the ratio of anchor rode length to water depth. More scope (e.g. 7:1 instead of 5:1) lowers the angle at the anchor and usually improves holding. All-chain rode can use 5:1 to 7:1 in normal conditions; rope or mixed rode often needs 7:1 to 10:1. In strong wind or waves, increasing scope helps. Always allow for swing room.
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Frequently Asked Questions
What scope for all chain?
In calm conditions 5:1 is often sufficient. For stronger wind or overnight anchoring, 7:1 is safer. In storm conditions, more scope (up to 10:1 if room allows) improves holding.
Do you include freeboard in scope?
Scope is calculated from water depth to seabed. When deciding how much rode to pay out, add the height of your bow above the water so the anchor sees the correct angle; the ratio is still depth to rode length.