The transportation of heavy or bulk cargo that is very large and irregular in dimensions is not easy as they cannot be transported in standardised containers. They require special containers called flat rack containers. These containers enable the cargo to be loaded from the top or sides. Majorly used for transporting cargo like machinery, pipes, boats, construction equipment, cranes, etc. that does not fit into standard containers.
Flat racks are available in standard 20ft or 40ft sizes and have numerous lashing rings fixed in the side rails, floor, and corners of the container to provide flat rack lashing to the cargo. Apart from the dimensions of flat racks being different in length, the width and height are often similar. They also come in two different forms: Fixed end flat racks or non-collapsible flat racks and collapsible flat racks.
· Non-collapsible Flat Rack: A flat rack that has fixed ends on the short sides of the container. They are stronger in construction so can endure greater top loads.
· Collapsible Flat Rack: The sides of the flat rack can be collapsed so the empty container can be easily shipped and stored more efficiently.
A few guidelines that need to be followed to secure cargo on flat racks before transportation are:
• Positioning of Cargo
The cargo should be positioned on the flat rack to ensure suitable weight distribution, both along the length and width, so that the centre of gravity of the cargo is as close to the centre of the flat rack.
• Weight Distribution
Flat racks are designed to carry heavier and more concentrated loads than standard equipment. As the strength of a flat rack lies in the two bottom rails the cargo must either rest on these rails or ensure suitable weight distribution both along length and width. Even though a maximum payload is marked on the flat rack, the maximum weight that can be carried is dependent on the length of the cargo resting on the rails.
• Anti-slip Material
Wood dunnage or anti-slip material like rubber mats should be used to avoid any contact of metal to metal surfaces. They should be placed between metal cargo surfaces and the flat rack bottom rails. The usage of anti-slip material helps to generate high friction thus decreasing the quantity of lashing required.
• Lashing
Cargo must be secured in the flat rack container by using materials that are suitable for the size, construction, and weight of the shipment.
A few points that need to be followed during flat rack lashing are:
• Avoid usage of different lashing materials on the same cargo or at least for securing in the same lashing direction
• Web lashings require edge protection on sharp corners.
• Different lashing materials have different elasticity and create unequal lashing forces
• Avoid knotting in web lashings as their breaking strength would be reduced by at least 50 percent
• Turnbuckles and shackles should be secured properly to avoid them from opening during transit
• For chains and web lashings the maximum securing load is considered to be 50 percent of the breaking strength
