Calculate the recommended anchor rode length - for all-chain or rope-and-chain rodes, in metric or imperial units. Includes tide, bow height, scope ratio, and a catenary visualization.
Enter the water depth to start the calculation.
Scope is the ratio of deployed rode length to effective depth (water depth + tide + bow height). An anchor holds best when the pull arrives horizontally at the seabed. Chain forms a catenary curve under its own weight and absorbs gusts; rope hangs nearly straight. Classic rules of thumb like 5:1 or 7:1 give too little rode in shallow water and unnecessarily much in deep water. The formula "50 ft (15 m) + 2 × depth" (all chain) or "50 ft (15 m) + 4 × depth" (rope + chain) compensates for this and is designed for winds up to about 30 kn. Above that, the calculator applies a surcharge: ×1.25 up to 40 kn, ×1.5 up to 50 kn, ×2 in storm conditions. In poor holding ground, let out even more.
All values are non-binding recommendations without guarantee. Safe anchoring remains the skipper's responsibility – always consider the holding ground, weather development, swinging room, and manufacturer guidance.
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