West of England P&I Club Loss Prevention Safety Alert
The West of England P&I Club has issued new Loss Prevention Safety Alert regarding wire damage and failure of pedestal cargo cranes.
Signs of crane wire damage include worn or broken strands in the hoist or luffing (topping) wires, or deformed wire that has stretched or kinked. This may lead to delay and off-hire disputes between owners and charterers as replacing the wire requires the crane to be taken out of service. If not, the crane wire may fail, possibly with catastrophic results. Hoist wire failure may cause hook blocks, cargo handling equipment and cargo to be dropped. Luffing wire failure may lead to the jib head falling on to the deck or quay or into the hold. In some cases the jib itself has buckled and collapsed. All incidents of this type may damage the load, stowed cargo, ships gear or stevedoring equipment, together with the risk of someone being injured, possibly fatally.
Causes of Damage
Using cranes to pull or drag cargo from the wings and ends of the holds by slewing the crane and/or hoisting loads when the wire is at an angle to the vertical can impart huge side forces. Cranes are not designed for this purpose and using them in this way is a common cause of wire and jib problems. Trying to place cargo in a difficult area by swinging the load towards it is also unacceptable as this may damage the hoist wire; the wire should always be vertical when the load is landed. Moreover, the side forces imparted during such a practice can cause the wire to be pulled off the jib head sheaves and become jammed.
If anchored in an exposed position, the movement of the vessel due to wind and wave action may produce dynamic loads in the crane, increasing the magnitude of any side forces. The same effect may be experienced by vessels with a list. As far as practicable, vessels should always be kept as near to upright as possible when using their own cranes.
In order to gain access to the extremities of a cargo hold, the hook block is often placed underneath the hatch coaming. This may result in the hoist wire chafing along the edge of the coaming and sustaining mechanical damage. Similarly, raising the hoist wire when it is lying alongside the hatch coaming will increase the risk of the hook block becoming caught underneath. This may damage the block or hoist wire and cause them to fail.
If a crane block is lowered at high speed and lands heavily, the shock may cause the hoist wire to jump off the sheaves at the jib head and become jammed as it suddenly slackens off. Ridingturns may also form on the hoist drum, damaging the wire underneath.
Recommendations
During cargo operations the duty officer should watch out for any signs of poor crane driving, particularly if the vessels cranes are being operated by stevedores or other third parties. If improper crane handling is observed, the duty officer should stop the crane immediately and explain their concerns to the foreman and the crane driver. If a critical situation appears to be developing it may be necessary to activate the cranes emergency stop, but only if it is safe and practicable to do so. Should the vessels cranes continue to be operated in an unsatisfactory manner in spite of such measures, the Master should issue a Letter of Protest to everyone concerned. The vessel should also try to take photographs and/or video footage of cranes that are being operated in an unacceptable manner in order to mitigate any related claims that may arise.
Cranes should never be used to drag the load to a better position before hoisting, either inside the holds or on the quay. When discharging, if the cranes hook cannot be plumbed vertically, suitable stevedoring equipment such as fork lift trucks, bobcats, payloaders, wheel loaders or excavators should be used to move the cargo into the hatch square so that it can be lifted straight out of the hold.
Cargo should always be hoisted slowly and smoothly to avoid snatch and shock loads which may damage the wire. Should damage to the crane or wire occur while handling cargo, the load should be lowered to a safe area at the earliest opportunity. If any wires appear to have jammed, the crane should be positioned to minimise the risk of personnel, the vessel or property being harmed should the wire suddenly part or break free.
Crane jibs are sometimes fitted with a bar running across the head block to prevent slack wires jumping off the sheaves and jamming. If not already fitted, Members may wish to consider equipping their cranes with this simple device.
Limit switches fitted to crane jibs to restrict luffing should never be overridden to expedite cargo handling. The only occasion when limit switches may be overridden is when stowing or unstowing the jib. At all other times the keys for overriding the limit switches should be protected from unauthorised use and should not be left in the crane cab. To prevent tampering with the limit switch, consideration should be given to fitting protective measures over the limit switch key slot.
Illustrative notices may be placed inside crane cabs to caution against unsatisfactory practices such as dragging loads and running hoist wires against hold steelwork.
Source and Image Credit: West of England P&I Club
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