Crane block failures on IHI and IHI-WMMP deck cranes

Published on November 9th, 2012, back to: News

Maritime NZ has issued a Safety Bulletin to draw attention to a number of recent crane block failures on IHI and IHI-WMMP deck cranes on log ships and to make available advice from the manufacturer as to the correct operation of the cranes and their recommended remedial action.

There have been a number of failures of crane blocks on 30 tonne IHI deck cranes on log ships in New Zealand over the past year. Fortunately there have been no serious injuries as a result of these failures to date, but any crane failure is potentially very serious.

The crane manufacturer IHI Corporation has proposed a modification to the blocks on this type of crane, as detailed in the attached bulletin (IHI ref. NGO-6185, 22 June 2011), to eliminate or reduce the incidence of such failures.

IHI suggests that at least some of these failures may have been attributable to slewing loads without lifting first, resulting in damage to the blocks due to side loading and subsequent failure over time.

However, no independent evidence has been presented to support this view, and there may well be other factors involved in the failures. While Maritime New Zealand (MNZ) is providing a copy of IHI's bulletin to highlight safety issues with the cranes, MNZ is not in a position to endorse IHI's views as regards the mode of failure.


  • Crane operators and ship operators should check, as a matter of good practice, before cargo handling commences, that all crane components are in good condition and there is no sign of damage or excessive wear to crane blocks
  • Ship operators should take note of the crane manufacturer's recommendations for modifications to crane blocks and undertake remedial action as they see fit
  • Competent persons and ship operators should ensure that if, after consideration of the manufacturer's recommendations, modifications to crane blocks are carried out (either permanent or temporary modifications or any repairs), that this work is appropriately certified. Standards for testing, inspection and examination of cranes on ships are covered by Maritime Rules Part 49: Ships' Lifting Appliances. In undertaking any testing, inspections, repairs or modifications of
    ships' cranes, the requirements of Part 49 must be adhered to
  • Crane operators should ensure that they adhere to the crane manufacturer's specified operating parameters and loading limit s at all times, and be aware of the potential for failure caused by incorrect lifting

Source: Maritime NZ

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