Wind Load Calculator
Calculate wind forces on project cargo
Wind Load Calculator
Calculate wind forces on project cargo using Bernoulli's equation. Determine lashing requirements and assess operational risks for maritime transport.
Wind Pressure
118 Pa
Wind Force
6.20 kN
Beaufort Scale
Force 5
Risk Level
Low Risk
Projected area perpendicular to wind direction
Fresh Breeze
Moderate waves, many white horses
Wind Pressure
118
Pa (N/m²)
Wind Force
6.20
kN
Low Risk
Standard lashing sufficient
Lashing Force Required
SF = 1.5x0.00 kN
Friction contribution: 1581%
Used for friction calculation
Wind load is the force exerted by moving air on structures or objects. For maritime cargo, wind load is a critical factor in securing cargo on deck, particularly for project cargo and out-of-gauge shipments.
The force depends on wind speed, air density, the exposed surface area, and the shape of the cargo. Using Bernoulli's equation, we can calculate the wind pressure and resulting force on cargo.
P = ½ × ρ × v²
F = P × A × Cd
Wind Speed
Force ∝ speed² (doubling speed = 4× force)
Surface Area
Larger area = more wind force
Shape Factor
Cd ranges from 0.35 to 1.28
Apparent Wind
Ship speed affects actual wind
Flat Plate/Square
Cd = 1.28
Highest drag
Large flat panels
Cube/Box
Cd = 1.05
Standard cargo
Containers, crates
Vertical Cylinder
Cd = 0.82
Moderate
Tanks, silos
Horizontal Cylinder
Cd = 0.60
Lower drag
Pipes, logs
Sphere
Cd = 0.47
Low drag
Pressure vessels
Angled Surface (45°)
Cd = 0.75
Reduced drag
Angled structures
Streamlined
Cd = 0.35
Lowest drag
Aerodynamic shapes
Complex Structure
Cd = 1.20
Variable
Machinery, equipment
Apparent wind is the wind experienced by a moving vessel, combining the true wind with the effect of the ship's own motion through the air.
Key Principles:
- • Headwind: Apparent wind speed increases
- • Following wind: Apparent wind speed decreases
- • Beam wind: Direction shifts toward the bow
- • Faster ships = greater apparent wind effect
Example Calculation
- •Account for worst-case weather along the route
- •Consider apparent wind from ship speed
- •Use rubber mats to maximize friction benefit
- •Apply minimum 1.5x safety factor for lashings
- •Calculate for both true and apparent wind
- •Include gust factors in calculations (typically 1.2-1.5x)
- ✗Ignoring the squared relationship of wind speed
- ✗Not accounting for ship speed effect on apparent wind
- ✗Using incorrect shape factor for cargo geometry
- ✗Assuming constant wind direction throughout voyage
- ✗Neglecting gust effects and weather variations
| Force | Description | Speed (knots) | Cargo Operations | Securing Level |
|---|---|---|---|---|
| 0-3 | Calm to Gentle Breeze | 0-10 | Normal operations | Standard |
| 4-5 | Moderate to Fresh Breeze | 11-21 | Normal with caution | Enhanced |
| 6-7 | Strong Breeze to Near Gale | 22-33 | Restricted operations | Maximum |
| 8-9 | Gale to Strong Gale | 34-47 | Suspended | Shelter required |
| 10-12 | Storm to Hurricane | 48+ | Dangerous | Delay departure |