Cargo Lashing Methods Explained: Blocking, Lashing and Locking

Securing cargo for road, rail or sea is a discipline with defined methods, not improvisation. Understanding the three securing principles — and the lashing types within them — is the difference between a load that stays put and one that shifts. Here is the clear breakdown.

The three securing methods

All cargo securing reduces to three approaches, usually used in combination:

1. Blocking

Blocking uses wedges, chocks and bracing to physically stop a unit from moving against other cargo, the vehicle structure, or container walls. When a unit cannot slide because something solid is in its way — and its centre of gravity sits below the top of the blocking — it is prevented from both sliding and tipping. Blocking is the first line of defence: remove the room to move.

2. Lashing

Lashing uses straps, web lashings, chains or ropes under tension to hold cargo down or in place. There are two main types (below).

3. Locking

Locking mechanically locks the cargo to the load carrier — the clearest example being the twist locks that secure containers to a ship or chassis. The cargo and carrier become one rigid assembly.

Two kinds of lashing: top-over vs direct

This distinction is where most people get lashing wrong.

• Top-over lashing (friction lashing): the lashing passes over the top of the cargo and presses it down onto the load bed. It does not restrain the cargo directly — it works by increasing the friction between the cargo and the surface. The downward pressure plus the friction stops sliding. Effective only if there is enough friction to begin with.
• Direct lashing (loop lashing): the lashing attaches directly to the cargo and to anchor points, applying straight-pull tension to stop movement in a specific direction (lengthwise, sideways). It restrains the cargo directly, not just through friction.

Web (textile) lashing is the most common equipment, frequently used as a top-over lashing.

Where unit-level securing fits

Blocking, lashing and locking all operate at the vehicle or container level — they secure units to the transport. But they assume each unit is already stable. A lashing over a pallet whose load was never strapped to its base just presses down on a stack that can still shift within itself.

That is why securing is layered:

1. Unit level: each pallet's load strapped to its pallet base at consistent tension — so the unit is solid. Calibrated machines such as the ErgoPack 726X, GO and 700 make this repeatable.
2. Transport level: the solid units then blocked, lashed and/or locked to the vehicle or container.

Skip the unit level and the transport-level lashing has nothing solid to hold. See how to load a shipping container and how to load a truck trailer.

Cargo securing checklist

• Blocking: voids filled, chocks/wedges stop sliding and tipping
• Lashing: correct type — top-over for friction, direct for restraint
• Locking: twist locks / mechanical locks where applicable
• Lashings rated and tensioned to the load
• Each pallet/unit already strapped to its base (the layer underneath)
• Securing matched to the journey (road/rail/sea forces)

Secure in layers — solid units first, then blocked, lashed and locked to the transport — and the load arrives exactly where it started.