Crane Attachments and Rigging

Crane attachments and rigging are the items between a crane hook and the load. The Category covers hook blocks and overhaul balls, spreader bars and lifting beams, shackles, wire rope, chain and synthetic slings, master links, offshore container lifting sets, pipe grabs and load cells. Each item needs a readable identification mark and working load limit (WLL) that trace to its certificate.

How the rating chain works

Every component in a lift must carry its share of the load with the dynamic factor included. Sling angle changes that share. As the legs spread from vertical, each leg's tension rises, so a sling's WLL is quoted for an angle range. The marked rating on a multi-leg sling already allows for uneven loading between legs, so never add up the leg ratings.

Item types

Item	Common standards	First thing to check
Shackles	US Federal Specification RR-C-271, EN 13889	Pin straightness, jaw opening, thread
Wire rope slings	EN 13414-1	Broken wires, ferrule condition
Chain slings	EN 818-4	Link wear and stretch
Webbing and round slings	EN 1492-1, EN 1492-2	Cuts, heat damage, legible label
Container lifting sets	EN 12079-2, ISO 10855-2	Sized for the container's gross mass
Spreader bars and beams	Design calculation to class rules	Welds and pad eye holes

Hook blocks and overhaul balls belong to the crane and are certified with it. Pipe grabs are hydraulic tools certified as lifting attachments.

Key specifications

Parameter	Why it matters	Typical classes or units
WLL	The load the item may lift in service	t (short tons)
Design factor	Ratio of minimum breaking load to WLL	Ratio, by standard
Sling angle range	WLL applies only within it	degrees from vertical
Grade or material	Sets strength and temperature limits	Chain grade, rope class, polyester
Pin and bow size	Must suit the pad eye and hook	mm (in)

Standards and certification

New items come with a manufacturer's certificate stating the proof test. On classed units, DNV-ST-0378 and equivalent rules cover loose gear. Container lifting sets are designed and certified under DNV-ST-E271 (DNV 2.7-1), EN 12079-2 or ISO 10855-2, and periodically inspected under DNV-ST-E271 or ISO 10855-3 at intervals of no more than 12 months. In the UK sector, LOLER requires a thorough examination of lifting accessories at least every 6 months.

Failure modes and inspection

Shackles. Look for a bent or worn pin, spread jaws, thread damage and wear at the bow.
Wire rope slings. Look for broken wires, kinks, birdcaging, corrosion and cracked or moved ferrules.
Chain. Look for stretched, gouged, twisted or nicked links, and measure link wear.
Synthetic slings. Look for cuts, abrasion, heat or chemical damage and a missing label.
Hooks. Measure throat opening against the original, check saddle wear and latch function.
Spreader bars, beams and pipe grabs. Run magnetic particle inspection on welds and pad eyes, and function test pipe grab hydraulics.
Load cells. Check the calibration date and indicator function.

Documentation

Certificate for each item, linked by its identification number
Proof test record and material certificates for heavy items
Examination register showing the last thorough examination
Design calculations and drawings for spreader bars and beams

An item whose mark no longer traces to a certificate has no offshore value, however good it looks.

Integration and compatibility

Match shackle pin diameter to the pad eye hole, since a loose fit overloads the pin and the hole edge. Check that the shackle bow seats in the crane hook, and that the whole rigging arrangement fits under the hook with the headroom you have. Size container lifting sets to the gross mass of the specific container, not to the crane.

Refurbishment and recertification

Unused surplus shackles, master links and spreader bars in original packing with proof test certificates are often a good choice. Used slings rarely are, because their history is hard to prove. Spreader bars and beams can be recertified by inspection, NDT and a proof load test, and a bar without drawings needs its rating recalculated first. Crosby and Van Beest (Green Pin) are widely used shackle makers. See also deck cranes and offshore containers and baskets.

FAQ

Frequently asked questions

Is it safe to buy used lifting slings and shackles?

It can be, if each item is marked, traces to its certificate and passes a thorough examination. Unused surplus shackles with original certificates are a common choice. Used slings are harder to justify because their load and exposure history is rarely known.

What certificates do offshore container lifting sets need?

A lifting set needs a certificate showing it was made and proof tested to DNV-ST-E271, EN 12079-2 or ISO 10855-2, plus current periodic inspection records. It should be sized for the gross mass of the container it is fitted to, and its inspection date should cover your mobilisation.

Can a used spreader bar be recertified?

Yes. A competent person checks the design rating, inspects the welds and pad eyes with crack detection, proof load tests the bar and issues a new certificate. Without the original drawings and calculations, the rating has to be recalculated before the test.

How often do offshore lifting accessories need examining?

Under UK LOLER, lifting accessories need a thorough examination at least every 6 months, unless a written examination scheme sets otherwise. Container lifting sets are also inspected under DNV-ST-E271 or ISO 10855-3 at intervals of no more than 12 months.

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