Tug Bollard Pull Required
Estimate tug bollard pull needed for a given displacement based on Henn & Dunlop empirical rule used in major ports.
Displacement-based BP
80t
Wind lateral force
771.8kN
Wind-only BP (1.5× margin)
118.0t
Formula, assumptions, and limits
$$BP \approx 60 \cdot \tfrac{\Delta}{60000} + 0.2, \quad BP_\text{wind} = 1.5 \cdot \tfrac{F_\text{wind}}{g}$$
Port-authority rules of thumb: typical large tanker needs 1× BP per 100,000 dwt; bulker 1× per 80,000 dwt; box-ship 1× per 60,000 dwt. Use the larger of the displacement-based BP and wind-force BP for the controlling design case.
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $Δ$ | Ship displacement | t | loading computer |
| $A$ | Exposed side area above water | m² | GA plan |
| $V$ | Design wind speed | m/s | port rules |
| $BP$ | Bollard pull required per tug | t | result |
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