Berthing Energy Calculator

Inputs

Formula Used

This calculator applies a coefficient-based berthing energy model used in preliminary fender design checks.

• Cm: added mass factor accounting for entrained water.
• Ce: eccentricity factor representing rotational effects at contact.
• Cs: softness factor reflecting compliant contact and damping.
• Cc: configuration factor for approach and berth arrangement.
• SF: safety factor for uncertainties and design margin.

How to Use

1. Enter displacement for the expected berthing condition.
2. Set approach velocity based on pilotage and site limits.
3. Choose coefficients to match berth layout and vessel behavior.
4. Apply a safety factor for uncertainty and risk tolerance.
5. Review design energy and required rated fender energy values.
6. Export CSV or PDF to document assumptions and results.

Example Data Table

Professional Guide

1) Purpose of Berthing Energy Checks

Berthing energy is the work that a fender system must absorb when a vessel contacts the berth. In marine and coastal construction, this value supports preliminary fender selection, spacing decisions, and risk screening. Higher energies typically require larger fenders, stronger fixings, and careful structural detailing at the berth face.

2) Key Input Data and Sources

Start with reliable displacement for the expected berthing condition (ballast, part‑load, or fully loaded). Approach velocity should reflect pilotage procedures, local current and wind exposure, and any operational speed limits. Coefficients should come from design guidance, comparable terminals, or project standards, then documented for traceability.

3) Approach Velocity Benchmarks

Energy scales with the square of velocity, so small speed changes can dominate results. Controlled berthing often falls around 0.05–0.20 m/s, while harsher sites, tight basins, or limited tug assistance may justify conservative values. Use scenario testing in the form to compare “normal” and “adverse” operations transparently.

4) Displacement and Effective Mass

The calculator converts displacement from tonnes to kilograms, then applies an added mass factor (Cm) to represent entrained water moving with the hull. For many vessels, Cm can range roughly 1.5–2.0. This effective mass drives kinetic energy and is a practical way to capture hydrodynamic amplification without complex modelling.

5) Understanding Coefficients (Ce, Cm, Cs, Cc)

Eccentricity (Ce) increases energy when contact is offset and rotational effects occur. Softness (Cs) reduces energy when compliance and damping dissipate motion. Configuration (Cc) adjusts for berth arrangement, approach angle, and operational layout. Together, these factors help align the simplified energy model with real berthing behaviour.

6) Safety Factor and Design Margin

A safety factor is commonly applied to cover uncertainties in velocity, vessel mass, coefficient selection, and operational variability. Values near 1.0 suit well‑controlled conditions with strong data, while 1.2–1.5 can be appropriate where exposure is higher or information is limited. Record the rationale in your project files.

7) Using Results for Fender Selection

The design berthing energy (in Joules and kN·m) is a target for the fender system to absorb. The calculator also estimates required rated fender energy by dividing by efficiency, recognizing that not all theoretical energy is absorbed as rated performance. Always verify final selection against manufacturer curves and allowable reaction loads.

8) Reporting and Quality Control

Documenting assumptions is as important as the number itself. Use the CSV export for quick comparison across scenarios, and the PDF export for approvals and design records. Check units, confirm inputs, and review sensitivity to velocity and coefficients. Consistent reporting reduces disputes during procurement and construction handover.

FAQs

1) What displacement should I use?

Use the displacement for the most demanding expected berthing condition, often fully loaded or a defined design case. If operations vary, run multiple scenarios and retain the governing case for design documentation.

2) Why does velocity matter so much?

Because kinetic energy is proportional to V². Doubling approach velocity increases energy by four times. Even small speed changes can outweigh coefficient adjustments, so choose velocity carefully and justify it with operational controls.

3) What does the added mass factor represent?

Added mass accounts for water moving with the vessel during lateral motion. It increases effective mass and therefore kinetic energy. Typical preliminary values can be around 1.5–2.0, but use project guidance when available.

4) How should I pick the eccentricity factor?

Ce reflects off‑center contact and rotational effects at the berth face. Use design guidance, comparable berth layouts, and vessel characteristics. If uncertain, run a conservative Ce and document the assumption clearly.

5) What is fender efficiency in this calculator?

Efficiency represents the usable portion of design energy absorbed as rated performance. It helps translate theoretical energy into a practical rated energy target. Use manufacturer information and consider installation, aging, and operational conditions.

6) Are results suitable for final design?

This tool supports preliminary design and scenario screening. Final design should confirm coefficients, approach conditions, fender performance, and berth structural capacity using applicable standards, manufacturer curves, and project engineering review.

7) Why export CSV and PDF?

Exports improve auditability. CSV is useful for comparing cases and creating a design register. PDF is convenient for approvals, submittals, and handover records, keeping inputs and results tied to a dated report.