What lashing equipment is used? A guide to chain, wire rope, turnbuckles and web lashings

Selection starts with the forces the cargo will experience at sea, so the weight, dimensions, centre of gravity and securing points of the cargo must be known. Two items of the same weight, one a compact machine and the other a long girder, may call for completely different equipment.

The cargo surface also matters. Painted or coated surfaces may favour web lashings over chain, while steel products with sharp edges may require chain or wire because webbing can be cut. The ship's portable securing devices and their characteristics are listed in the Cargo Securing Manual.

Chain is widely used for heavy units, vehicles, construction machinery and steel products because of its high strength and low elongation. It is normally combined with a lever tensioner or a turnbuckle and fitted with hooks at the ends.

Links must be free of stretching, cracks, bending and heavy corrosion. A hook whose throat has opened up may indicate overloading. Running chain over a sharp edge can reduce its strength, so suitable protection at corners is advisable.

Wire rope offers a flexible solution for long lashings and large, irregular cargo. Eyes are usually formed with thimbles and secured with wire rope grips, and the lashing is tensioned with a turnbuckle.

Fitting the grips the right way round and in sufficient number, and terminating the wire correctly, are among the most critical points. The number and spacing of grips should follow the manufacturer's instructions and the ship's Cargo Securing Manual. Wire with broken strands, crushing, kinks or corrosion should not be used.

A securing arrangement is only as strong as the small fittings that connect it to the ship and the cargo. The weakest link sets the capacity of the whole system.

Polyester web lashings are light, quick to apply and gentle on cargo surfaces. They are common on crated machinery, cases, painted parts and medium-weight items. Each web should carry a legible label showing its rated capacity; webs without a readable label should be rejected.

Webbing is easily cut on sharp edges, so edge protectors should be standard practice. Webbing also stretches differently from chain and wire. Mixing materials of different elasticity in the same direction means the stiffer lashing picks up the load first, leading to uneven load sharing.

The service life of equipment depends heavily on how it is stored. Chains, turnbuckles and shackles should be kept dry and sorted by type and rating. Turnbuckle threads should be kept clean and greased; seized or rusted turnbuckles should be repaired or withdrawn before use.

Web lashings should be kept away from sunlight, chemicals and heat, and never stowed away wet. After discharge, released equipment should be counted and damaged items tagged and set aside. For the ship's own portable securing devices, inspection and maintenance records are kept as required by the Cargo Securing Manual.

The maximum securing load (MSL) is the highest load a securing device may be subjected to in service. It is not the breaking load; it includes a margin of safety. When assessing a securing arrangement, each component's MSL is used, and the lowest-rated item in the chain is decisive.

That is why equipment should be marked, certified and undamaged, visually checked before use, with doubtful items set aside. Karan Gözetim provides lashing and cargo securing services from Gemlik; the scope regarding equipment and execution is agreed at the quotation stage.