Provision Crane

What sets this type apart

A provision crane is built for occasional, light lifting rather than the sustained duty cycle of a cargo crane. Its structure, wire rope and hydraulic or electric power pack are sized around stores drums, pallets, spare parts crates and the occasional engine component, not repeated cargo hold cycles through a working day. On many ships it is the only crane fitted, since deck cargo is handled by shore cranes or the ship carries no cargo cranes at all, which makes its availability for provisioning and ship's spares handling more important than its lifting capacity.

Main components

Boom and slewing structure

A single hydraulic luffing boom, often telescopic, reaches from a fixed pedestal out over the ship's side or down into a stores hold. Slewing is powered, usually hydraulically, through a limited arc rather than a full 360 degrees on many installations.

Wire rope and hook block

A single-fall wire rope runs from the winch drum through the boom head sheave to a hook block; the SWL marked on the crane assumes the rope and sheaves are in the condition recorded at last inspection, not as-new.

Hydraulic power pack and winch

An electrically driven hydraulic pump supplies the luffing, slewing and hoisting cylinders and motors; a local control station and often a remote pendant let the operator work from a position with a clear view of the load.

Limit switches and overload protection

Slew limit, luffing limit and hoist upper-limit switches prevent the boom driving into the ship's structure or two-blocking the hook against the boom head; an overload cut-out stops hoisting or luffing before the rated SWL is exceeded.

Selection and sizing

Sizing follows the heaviest single item routinely handled, such as a full drum of lubricating oil, a spare turbocharger cartridge, or a loaded pallet, plus margin, rather than an average provisioning load.

Regulations and class

Lifting appliances including provision cranes fall under class and flag lifting gear survey requirements, with annual thorough examination and periodic proof-load testing at a multiple of SWL, carried out by an approved surveyor. The crane's test certificate and load chart must be kept on board and available for port state control inspection, and a crane operated past its due proof-load date is a common detention item.

Typical faults

• Wire rope corrosion from weather exposure - reduced breaking strength not visible without close inspection, especially at the socket and drum anchorage.
• Hydraulic seal leakage - slow load drift or loss of luffing hold, often first noticed as the boom creeping down under a static load.
• Limit switch drift or failure - boom driven into structure, or hook two-blocked against the head sheave.
• Corroded pedestal bolting - a structural item easy to miss under paint, checked at survey but worth a visual check before use in exposed locations.
• Overload cut-out bypass or failure - loss of the one safeguard against exceeding SWL, usually found only when tested.

What to look for in a supplier

• Spare hydraulic seals, limit switches and wire rope matched to the specific crane model rather than generic equivalents.
• Willingness to support the proof-load test and thorough examination cycle rather than only selling parts.
• Clear load charts covering the full outreach range the crane is actually used across on board.

Check the proof-load test date on the crane's certificate before every provisioning operation that involves a heavier-than-usual item - a crane rated for stores duty has little reserve capacity if pushed toward its SWL with an aged wire rope.