Inputs
Choose simplified or detailed mode. Angles are in degrees.
Formula used
Each mooring line tension is converted to kN, multiplied by the dynamic factor DAF, then resolved into horizontal and vertical components using the vertical lead angle.
- Tdyn = T × DAF
- Th = Tdyn × cos(θv)
- Fz = Tdyn × sin(θv)
- Fx = Th × cos(θh)
- Fy = Th × sin(θh)
- ΣFx, ΣFy, ΣFz are summed across all active lines.
- H = √(ΣFx² + ΣFy²)
- R = √(ΣFx² + ΣFy² + ΣFz²)
- Design Load = R × SF
Angle notes
θh is the line’s horizontal lead angle. θv is the line’s vertical lead angle (up positive).
In simplified mode, the total spread is distributed evenly about the lead angle.
How to use this calculator
- Select a mode: Simplified for equal line tension, or Detailed for different lines.
- Enter DAF and SF based on your design basis.
- Provide line tensions and angles. Use realistic lead angles from layout drawings.
- Optionally enter bollard capacity to see utilization.
- Click Submit to show results above the form.
- Use the download buttons to export CSV or PDF reports.
Example data table
Example inputs and representative outputs (for illustration only).
| Scenario | Lines | T per line (kN) | Lead (°) | Spread (°) | DAF | SF | Design load (kN) |
|---|---|---|---|---|---|---|---|
| Along-quay breast + spring | 2 | 200 | 20 | 10 | 1.30 | 1.50 | ~770 |
| Three-line shared bollard | 3 | 180 | 35 | 20 | 1.50 | 1.60 | ~900 |
| Mixed tensions (detailed) | 3 | 250 / 200 / 150 | 15 / 25 / 10 | — | 1.40 | 1.50 | ~980 |
Use the calculator for exact values based on your geometry.