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Lashing Force Calculator

Calculate cargo securing requirements

Free Tool
Maritime Safety
CSS Code Compliant
IMO Standards

Lashing Force Calculator

Calculate required lashing forces for project cargo securing based on IMO CSS Code standards. Analyze ship accelerations, select appropriate equipment, and ensure compliance with maritime safety regulations.

5 Ship Types
11 Equipment Types
CSS Code Formulas
47
Lashings Required
624.3 kN
Total Force
4.33
Safety Factor
SAFE
Compliance
Cargo Parameters
Enter cargo dimensions and weight

Height of CoG from base of cargo

Vessel Configuration
Select ship type and deck position

Large vessel for bulk commodities like grain, coal, or ore

Exposed to weather, highest forces

Longitudinal
0.5g
Transverse
0.7g
Vertical
1g
Calculation Parameters
Adjust friction coefficient and lashing angle
0.1 (Steel on Steel)0.400.7 (Rubber on Steel)
15°45°75°

Optimal angle: 45° (balanced horizontal/vertical restraint)

Lashing Results
Calculated lashing requirements

Longitudinal

245.3

kN

Transverse

343.4

kN

Vertical

490.5

kN

Total Lashing Required

47 lashings

624.3 kN

Equipment: Wire Rope 20mm

Safety Factor: 4.33

Compliant with CSS Code

Friction Contribution57%

Friction reduces required lashing force by 57%

45°
Lashing Angle
✓ Optimal
0.40
Friction Coeff
✓ Good friction
Quick Reference
Minimum safety factor: 1.5 (CSS Code)
Optimal lashing angle: 45° from horizontal
Heavy weather routes: Use SF 2.5-3.0
Always use certified lashing equipment
What is Lashing?

Lashing is the process of securing cargo to prevent movement during transportation by sea, road, or rail. It involves using various securing equipment like wire ropes, chains, webbing straps, and turnbuckles to restrain cargo against forces generated by vehicle or vessel motions.

For project cargo and heavy lift shipments, proper lashing is critical for safety and regulatory compliance. Incorrect lashing can lead to cargo damage, vessel instability, and serious accidents.

Forces on Cargo

Longitudinal (Fore/Aft)

0.3-0.5g depending on ship type

Transverse (Athwartship)

0.5-0.8g - most critical

Vertical

0.6-1.0g - affects friction

Safety Factors
  • 1.5: Minimum per CSS Code
  • 2.0: Standard practice (recommended)
  • 2.5-3.0: Heavy weather conditions
  • Always use SWL (Safe Working Load), not MBL
Friction Coefficients Reference
Common material combinations for cargo securing

Steel on Steel (dry)

0.1-0.2

Lowest

Steel on Steel (oily)

0.05-0.1

Avoid

Steel on Wood

0.4-0.5

Good

Steel on Rubber

0.6-0.7

Excellent

Wood on Steel

0.3-0.4

Standard

Wood on Wood

0.3-0.5

Common

Concrete on Steel

0.4-0.5

Good

Rubber mat

0.6-0.8

Best

Pro Tips
  • Use rubber mats to maximize friction benefit
  • Optimal lashing angle is 45° from horizontal
  • Always protect lashings from sharp edges with edge protectors
  • Re-tighten lashings 24 hours after initial tensioning
  • Document the lashing plan with photos and measurements
Common Mistakes
  • Using MBL instead of SWL for calculations
  • Ignoring the effect of lashing angle
  • Over-tensioning causing equipment damage
  • Not accounting for heavy weather routes
  • Lashing to structurally weak points on cargo
Frequently Asked Questions