By Evan_Yao    Photo：CANVA

In international heavy-lift cargo transportation, OOG (Out-of-Gauge) cargo refers to shipments that exceed the external dimensions of a standard container in length, width, or height. Such cargo must usually be transported using Flat Rack (FR) containers.

A Flat Rack has no roof or side walls, only a base and two end walls, making it ideal for over-length, over-width, over-height, and irregular heavy cargo. Due to its open structure, compliance of lashing and securing directly determines whether the cargo will be accepted by the port, loaded smoothly, and transported safely by sea.

Taking the operational requirements of Ningbo Port as an example, this article summarizes the standards for OOG/Flat Rack lashing, road checks, port restrictions, and common NG (rejection) reasons for frontline operations reference.

1. Core Lashing Standards for OOG / Flat Rack at Ningbo Port

Lashing requirements at Ningbo Port comply with port regulations and international maritime standards.

All lashing and securing must be completed before port entry; on-site modifications are not allowed.

1.1 Dimension and Weight Limits

• Over-height (from the base of the Flat Rack to the highest point of the cargo, including dunnage and supports):
  • Routine approval limit: ≤ 250 cm
  • Special approval required: 250–290 cm (subject to shipping line confirmation, vessel stowage, and vessel/route restrictions)
  • Hard limit: ＞ 290 cm (extremely difficult to approve; multi-party coordination required; final approval subject to road transport and vessel stowage)
• Single-side over-width (extension beyond the Flat Rack base): ≤ 120 cm
• Single-end over-length (extension beyond the Flat Rack end): ≤ 200 cm
• Total weight (cargo + Flat Rack tare weight, excluding chassis): ≤ 50 tons

(Overweight cargo requires confirmation of crane capacity, vessel load, and road transport. Always check the container’s MGW plate – never exceed the manufacturer’s rated weight.)

1.2 Lifting Points & Corner Casting Protection (Critical Rejection Items)

• Covering the 4 corner castings with cargo or lashing materials is strictly prohibited.
• A clearance of ≥ 30 cm must be maintained between cargo and end walls; otherwise, port cranes cannot operate safely.

1.3 Mandatory Lashing Requirements

• Steel wire rope diameter: ≥ 16 mm
• Wire rope clips: 3 pieces per set, spaced 5–10 cm apart, nuts facing the same direction
• Steel wire ropes must be tensioned with turnbuckles
• Nylon lashing belts must use ratchet fasteners
• Plastic edge protectors must be used at all contact points; cartons or cloth are not allowed
• Shaft and coil cargo must be protected with plastic sleeves to prevent abrasion

1.4 Center of Gravity & Load Distribution

• Cargo center of gravity must be centered and evenly distributed; unilateral eccentricity is prohibited.
• High-center-of-gravity cargo must be lowered or supported.
• Each lashing point: ≤ 5 tons; concentrated loading on single points is prohibited.

1.5 End Walls & Dunnage Requirements

• Both end walls must be erected or lowered simultaneously; one-up-one-down is forbidden.
• If end walls are lowered for over-length cargo, ensure they do not exceed road width limits and are securely fixed to the chassis.
• Wooden dunnage must be used for anti-slip; nails are not allowed to secure dunnage.
• Supports must be installed between cargo and end walls to prevent longitudinal movement during sea transport.

2. OOG Admission & Inspection Process at Ningbo Port

Ningbo Port applies a strict triple-check mechanism:

1. Written Application by Shipping Line

Submission of container details, stowage plan, CoG & lifting point diagram, lashing plan, and transport method.

2. On-site Port Inspection

Non-compliant cargo may be rejected directly.

3. Third-Party Inspection (Mandatory for Selected Routes)

Required for routes to India, Pakistan, Southeast Asia, etc., with certification issued before gate-in.

Over-sized cargo also requires a multi-party coordination meeting and vessel release approval before gate-in.

3. Top 5 Common NG (Rejection) Reasons at Ningbo Port

According to port operational feedback, over 60% of OOG delays or rejections are caused by:

1. Incomplete or inaccurate documentation

Missing CoG drawings, loading diagrams; vague dimensions/weight such as “approx.” without precise figures.

2. Offset center of gravity or unbalanced loading

Causes excessive structural stress at sea and is classified as high-risk.

3. Blocked corner castings or insufficient clearance

Cargo too close to end walls, covered corner castings, or clearance < 30 cm.

4. Overloaded lashing points

All force concentrated on 1–2 points, risking frame deformation or damage.

5. Missing or substandard protection

Using cartons or cloth instead of professional plastic protectors, leading to damage and hazards.

4. Key Points for OOG / Flat Rack Road Check

A “road check” is a pre-loading on-site verification to ensure compliance. Key items:

• Actual dimensions and total weight within port limits
• Both end walls in synchronized position
• Even and balanced center of gravity
• All corner castings fully exposed; clearance ≥ 30 cm
• Properly distributed lashing points within load limits
• Steel wire ropes, clips, protectors, turnbuckles meet standards
• Wooden dunnage without nails, adequate support
• Full photos and videos recorded for inspection and record-keeping

Conclusion

When handling OOG / Flat Rack cargo at Ningbo Port, acceptance and smooth shipment depend

not on whether the cargo “fits”, but on whether it is properly secured in accordance with maritime standards.

Strict compliance with port requirements and thorough pre-loading road checks will minimize rejection, detention, and rolling risks, ensuring cargo safety, schedule stability, and avoiding extra costs and delays.

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