3. Cargo Securement: Understanding Movements and Forces in Road, Rail, and Sea Transport
Every day, millions of containers are shipped worldwide. Yet, a large portion of transport incidents result from improper cargo securing.
👉 25% of road accidents involving trucks are caused by inadequate load securing.
👉 66% of ocean accidents are due to poor packaging or load restraint.
If we need a seatbelt, then our cargo does too.
⚠️ What We Want to Avoid
Damaged or crushed products
Danger when opening container doors
Time loss due to re-palletizing or repacking
Delays and financial losses
A single container can travel by sea, by road, and by rail — it must therefore be secured for the worst-case scenario.
🚛 Road Transport: Sudden Stops and Direction Changes
We’ve all experienced a sudden stop at a red light when our laptop or bag slides forward, or a turn where a pack of cigarettes shifts across the dashboard.
These are the same forces of inertia acting on every cargo load during acceleration, braking, or turning.
Downward: 1G (gravity)
Forward/backward: up to 0.8G
Sideways: up to 0.5G
➡️ Without proper load securement solutions, cargo will inevitably move.
🚢 Maritime Transport: Roll, Pitch, and Heavy Pressure
At sea, there are no sudden stops — but continuous right-left and up-down movements.
Ocean swells can generate forces up to 2G.
This means a 500 kg pallet exerts a 1-ton pressure on the one below.
Cargo experiences:
Roll and pitch movements
Vertical shocks due to waves
Constant vibration and inertia
Proper securing is essential to prevent sliding, crushing, or collapse.
🚂 Rail Transport: High Longitudinal Shocks
In rail freight, shunting accelerations can reach 4G.
These longitudinal forces are the most abrupt.
Airbags are commonly placed along the container’s length to absorb impacts, often supporting the weight of multiple pallets — up to ten or more.
⚙️ The Physics Behind Cargo Securement
According to Force = Mass × Acceleration, the acting force depends on cargo weight and acceleration levels.
These are clearly defined in the CTU Code (freely accessible).
Retaining forces come from:
Gravity – ever-present but insufficient alone.
Friction – static friction between surfaces (wood-on-wood ≈ 45%).
Friction decreases with water, ice, or oil.
Use anti-slip mats to increase the coefficient of friction.
Lashing systems – tensioned straps, floor lashings, or nets providing securing in all four directions.
🔩 Professional Cargo Securement Solutions
1. Dunnage Airbags
Absorb impacts and fill void spaces
Suitable for sea, rail, and road
Withstand pressures up to several tons
Avoid right and left movements in containers
2. Floor Lashing Systems
Use the strongest container anchor points
Provide up to 10 tons of securing force
Limited only by the anchor point MSL
Avoid front and back movements in containers
✅ Conclusion
Cargo will always try to move — we must create equal or greater opposing forces to balance it.
When gravity, friction, and lashing are combined properly, equilibrium is achieved — and cargo stays safe throughout the journey.