Anchor Holding Power

MARITIME – ANCHORING & MOORING CALCULATOR Anchor Holding Power A precise tool.
📖
What is the Anchor Holding Power & How does it work?

Anchor holding power is the ability of an anchor‑seabed system to resist the forces that try to pull a vessel away from its mooring point. It depends on the anchor’s geometry, its weight, the type of seabed, and the amount of chain or rope deployed (the scope).

The interaction between the anchor and the seabed can be expressed with empirical coefficients that reflect how well the anchor bites into sand, mud, clay or rock. A larger fluke area or a heavier anchor generally increases the resisting force, while a softer seabed reduces it.

Designers use a simple formula to estimate the holding power and compare it with the vessel’s displacement and environmental loads. This helps ensure a safe margin before setting anchor.

H = C \cdot W^{0.5} \cdot S \cdot F \cdot \frac{L}{D}
H = Holding power (kN)
C = Empirical constant (≈0.5)
W = Anchor weight (kg)
S = Anchor size factor (m)
F = Seabed coefficient (dimensionless)
L/D = Scope ratio
⚙️
Parameters
Result —
❓
Frequently Asked Questions
What is anchor holding power?
Anchor holding power is the force required to pull a vessel away from its mooring point, influenced by anchor design, weight, seabed conditions, and chain length.
How does seabed type affect anchor holding power?
Different seabed types like sand, mud, clay, or rock require different anchors. Harder surfaces generally provide better holding power than softer ones.
What is scope in anchoring?
Scope refers to the ratio of chain length to water depth when a vessel is anchored. A common recommendation is 7:1 for safety and stability.
How does anchor weight impact holding power?
A heavier anchor typically provides more holding power because it can penetrate deeper into the seabed, creating better grip.
Why is it important to calculate anchor holding power?
Calculating anchor holding power ensures that a vessel remains securely moored in various weather conditions and prevents drifting or running aground.
What empirical coefficients are used in the calculation?
Empirical coefficients account for how well different anchors bite into various seabed types, such as sand, mud, clay, or rock.
How do I determine the right anchor size for my vessel?
Select an anchor size based on your vessel's weight and intended anchoring conditions. Larger vessels generally require anchors with greater holding power.

Results are for informational purposes only and do not constitute professional advice.