Anchor Catenary

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

An anchor chain behaves like a flexible cable that adopts a catenary shape under its own weight and the horizontal pull from the vessel. The curve is described by the hyperbolic cosine function, and its geometry determines the forces transmitted to the anchor.

The key geometric parameters are the horizontal distance from the vessel to the anchor (x), the water depth (h), and the total chain length (L). The difference between the actual chain length and the straight‑line distance, called the sag (s), controls the curvature of the catenary.

From the sag we can estimate the horizontal component of tension (H) and the total tension (T) in the chain. These tensions are critical for selecting an appropriate anchor and ensuring safe mooring under varying environmental loads.

s = L – sqrt{x^{2}+h^{2}}
s = sag (extra chain length beyond the straight‑line distance)
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Parameters
Result —
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Frequently Asked Questions
What is a catenary curve in maritime calculations?
A catenary curve describes the flexible cable shape of an anchor chain under its own weight and horizontal pull from the vessel.
How does the sag affect the anchor's performance?
The sag, or difference between actual chain length and straight-line distance, affects the forces transmitted to the anchor, impacting its holding power.
What is the significance of the horizontal distance in this calculation?
The horizontal distance from the vessel to the anchor determines the catenary curve's shape and influences the chain's sag.
How does water depth factor into the anchor chain calculations?
Water depth affects the total length of the chain that is submerged, which in turn impacts the catenary curve and forces on the anchor.
Can this calculator be used for different types of anchor chains?
Yes, the principles apply to various anchor chains, though specific material properties may influence results.
What is the hyperbolic cosine function's role in these calculations?
The hyperbolic cosine function describes the mathematical shape of the catenary curve formed by the anchor chain.
How do I interpret the results from this calculator?
The results provide the geometry and forces of the anchor chain, helping to assess the anchor's performance and potential holding power.

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