On most cargo ships, the heavy work on deck is done by hydraulics. Hydraulic pumps and motors drive the deck cranes, mooring winches, windlasses, hatch covers, steering gear and ramps. When a hydraulic pump or motor fails, a crane stops working or a winch cannot heave, and the vessel can lose time in port. Knowing which parts wear, and what to order, helps you get the right unit on board quickly.
Where hydraulic pumps and motors are used on board
- Deck cranes: a power pack of one or more axial piston pumps drives the hoisting, luffing and slewing motors.
- Mooring winches and windlasses: low-speed, high-torque radial piston motors, or high-speed motors with a gearbox.
- Hatch covers and ramps: pumps and cylinders that open, close and lock the covers.
- Steering gear: pumps that drive the rams or rotary vane actuator.
- High pressure tools and test units: air-driven pumps used for bolt tensioning and pressure testing.
The parts that wear first
- Pistons, slippers and the cylinder block in axial piston units, which wear and leak internally, so output and pressure drop.
- Valve plate and swash plate, which score when the oil is dirty or the unit runs hot.
- Bearings and shaft seals, the usual cause of noise and external oil leaks.
- Control valves and compensators, which cause unstable pressure or slow movements.
- Seal kits and O-rings, small items to order with every overhaul.
Most failures start with the oil. Water, dirt or overheating damage the precision parts, so change the filters and check the oil condition before you fit a replacement unit.
Used, reconditioned or new: which to choose
Used pumps and motors are original maker units removed from a vessel, inspected and tested. They are the fastest and lowest-cost option, and often the only exact fit for older crane and winch models.
Reconditioned units are stripped, measured and rebuilt with new bearings, seals and any worn rotating parts, then tested on a test bench. They give close to new performance at a lower price.
New units and spares, either OEM or quality equivalents, suit wear parts such as seal kits, bearings and piston sets, or a unit that runs every day.
Common makers on board
Ship hydraulics often use Bosch Rexroth axial piston pumps and motors (such as the A4VSO, A2F and A6VM series), Kawasaki pumps and Staffa motors, Hägglunds radial piston motors, and units from Kayaba, Nachi and Sauer-Danfoss. Many of these models have been updated over the years, so check the full type code before you order.
What to send your supplier
- A photo of the nameplate with the full type code and serial number
- The machine it serves, for example deck crane, winch or hatch cover, and the crane or winch maker
- Shaft and flange details, or a photo of the mounting side, if the nameplate is missing
- Quantity, vessel name or IMO number and the delivery port
- Whether you want used, reconditioned or new, or prices for all three
How AMAF Marine can help
AMAF Marine supplies marine hydraulic pumps and spares, hydraulic motors such as the Rexroth A6VM 160, air-driven high pressure pumps and deck machinery spares. We offer used and reconditioned original maker equipment, as well as new spares (OEM and quality equivalents). Used and reconditioned units are tested before dispatch and ship from our warehouse to any port.
Send us your nameplate photo and we will quote within 48 hours.
