Crane Block Failures on IHI and IHI-WMMP Deck Cranes

Following the failure of a number of crane blocks on vessels loading logs in New Zealand in recent years, Maritime New Zealand has published a Safety Bulletin addressing the issue.

The incidents have involved crane blocks fitted to 30 tonnes Safe Working Load (SWL) IHI and IHI-WMMP deck cranes. It would appear it is possible for the crane block’s side (cheek) plate to be bent outwards at the bottom, releasing the trunnion pin to which the hook is attached via shackles. The damage could be caused either by catching the bottom of a cheek plate on the ship’s structure, or by swinging a block against, for example, the inside of the hatch coaming, such that the momentum of the load causes the cheek plate to be bent outwards.

Members with vessels fitted with IHI and IHI-WMMP 30t SWL deck cranes are advised to check whether their crane blocks may be susceptible to the type of failure detailed in IHI’s Service Bulletin on this issue, and if necessary, arrange for suitable modifications to the crane blocks to reduce the possibility of such damage occurring.

Members requiring further guidance are advised to contact the Loss Prevention department.