Chocks: Anti-Rolling Cargo Restraint and Load-Securing Controls

A Chock Prevents Rolling, Not Every Movement

The SSDER glossary defines CHOCK as a wedge-shaped piece placed against a wheel or rounded object to prevent movement. In procurement, the term covers a control for reels, drums, cylinders, vehicles, pipes and other rolling units. A chock resists a defined direction; it does not automatically prevent sliding, tipping, lifting or bouncing.

The RFQ should identify the cargo geometry, mass, support surface, slope, route, handling equipment and required standard. Ask the supplier or load planner to explain how chocks interact with friction, blocking, braces and lashings. A low-cost chock is not a saving if it fails under braking or becomes a trip hazard during unloading.

Specify Geometry, Material and Contact

Record the wheel or drum diameter, width, contact angle, chock height, length, material, fastener or attachment method and allowable load. Timber, polymer, steel and purpose-designed composite chocks behave differently under moisture, compression and repeated use. Avoid a specification that says only “wooden wedges” without grade and dimensions.

The chock must contact the cargo and base correctly. Gaps, rounded edges, oily decks, damaged corners or a soft floor can reduce resistance. If the cargo can move in both directions, use a paired or through-chock arrangement and add a positive restraint when the risk assessment requires it.

Use CTU and Securing Principles

The IMO CTU Code and CSS Code encourage a systematic approach to packing and securing: understand forces, distribute weight, prevent movement, protect packages and inspect the result. A chock should be selected within that plan, with the friction coefficient, acceleration assumptions and lashing capacity stated when an engineered calculation is needed.

For road or rail, check braking, cornering, vibration and shunting forces. For ocean, consider vessel motions, wet surfaces and the container or deck’s lashing points. The responsible loader must know the approved method and the carrier or terminal must be able to reject an unsafe arrangement before departure.

Inspect at Each Handoff

Photograph the chocks in position, including contact, fasteners, blocking, lashings, cargo marks and the container or trailer ID. Record condition and any shift at origin, terminal, cross-dock and destination. A photo taken after a chock has been removed is not evidence of loading condition.

Define what happens when a chock is wet, split, missing, crushed or incompatible with a replacement trailer. Stop and correct the load when the control is not effective. The supplier, carrier and warehouse should report the event with a reason code so recurring damage is visible in the scorecard.

Worked Example: Reels on a Wet Floor

A supplier loads three steel reels in a trailer using small timber wedges. Rain wets the floor, the wedges contact only a narrow edge and no longitudinal lashing is fitted. During braking, one reel moves and damages the sidewall. The carrier and supplier each claim the other owned the securing decision.

The corrected specification uses sized, paired chocks with a defined contact angle, dry friction surface, blocking and lashings. The loader records the material, condition and photographs; the carrier confirms acceptance; and the contract assigns the cost of a failed or substituted restraint. Procurement then tracks movement, damage and corrective-action closure.

Metrics and Governance

For cargo chocks procurement controls, measure both service and evidence quality. Useful indicators include first-pass acceptance, exception rate, response time, unplanned cost, document completeness, damage or discrepancy rate, and the percentage of shipments that follow the approved process. A dashboard should distinguish a supplier failure from a carrier, terminal, broker or internal master-data failure.

Review the metric trend with procurement, logistics, finance, quality and the responsible specialist. Use a monthly exception sample to test whether the control worked in a real transaction, not just whether a field was filled. Repeated exceptions should change the sourcing strategy, contract, lane design or supplier development plan.

Keep the control proportionate to risk. High-value, regulated, time-critical or safety-sensitive cargo needs stronger evidence and faster escalation than a routine shipment. Record the decision owner, approval date, source documents and follow-up action so the next buyer can understand the operating history.

Supplier and Carrier Questions

• Which CHOCK or related glossary condition is assumed in your quotation, procedure or service description?
• Which party owns each data field, physical handoff, inspection, document and exception?
• What evidence will be available before release, loading, movement, receipt, invoice approval or claim?
• What changes require advance notice, requalification, a revised price or a new risk decision?
• How will the supplier report incidents, delays, mismatches and corrective actions, and within what response time?

Implementation Sequence

Implement the control in a small, representative lane first. Capture the baseline process, test the required data and evidence, run a real transaction, and review every exception with the people who performed the work. Do not declare the control effective only because a supplier signed a procedure.

After the first three shipments or operating cycles, update the purchase-order clause, work instruction, scorecard and training. Scale the control to other suppliers only when the evidence is repeatable and the owner can explain what happens when the normal path fails.

Common Mistakes to Avoid

• Assuming a chock alone prevents sliding, tipping and vertical movement.
• Specifying material without cargo diameter, load direction, dimensions or contact requirements.
• Ignoring friction loss from oil, moisture, paint, dirt or an unsuitable floor.
• Using damaged, improvised or mismatched chocks without a risk-approved replacement.
• Failing to inspect and photograph restraints at loading and later handoffs.

Procurement Implementation Checklist

• Define cargo shape, mass, diameter, surface, route and movement forces.
• Specify chock dimensions, material, grade, attachment and reuse limits.
• Design the complete system: friction, chocks, blocks, braces and lashings.
• Train loaders on placement, contact, floor preparation and rejection criteria.
• Record condition, photos, IDs and exceptions at each handoff.
• Trend shifts, damage, restraint failures, substitutions and corrective actions.

Frequently Asked Questions

Related Kurums Guides

• Cargo Manifest Controls
• Billed Weight and VGM Controls
• Shipping Documents for Procurement
• Customs Documents for Procurement
• Container Types and Load Securing
• Freight Contracts and Parties

Standards and Authoritative Sources

• IMO — CTU Code
• IMO — Cargo Stowage and Securing Code
• U.S. FMCSA — Cargo Securement Rules
• U.S. FHWA — Freight Management and Operations

Glossary terms covered: CHOCK, chock, blocking, friction, lashing, rolling cargo, CTU Code