Winch repair to support vessel project

Identifying the route cause of the fault and repairing the winch allows safe return to service


  • Route cause of fault rectified: the repeated failure of the hydraulic motor safety coupling will not reoccur
  • Equipment returned to service: winch repaired (hydraulic motor replaced) inclusive of dynamic pull test and brake test before re-installation


  • Bosch Rexroth referred the client to Sparrows, with the vessel due into Aberdeen harbour
  • The client was reporting repeated failure of the safety coupling on a Hagglunds Viking 64-series hydraulic motor, which was fitted to a 15t tow winch on-board
  • Sparrows mobilised a hydraulic supervisor to the vessel on a Sunday to investigate the issue., The winch initially operated smoothly, however after a period of time operation became very erratic
  • The case of the motor was found to be dry / air released on breaking into the motor drain line
  • The client required the winch back in service urgently for a project.


The winch was removed from the vessel and taken to Sparrows hydraulic workshop in Aberdeen. A spare hydraulic motor was provided by the client to fit in place of the existing hydraulic motor

In order to rectify the issue of the motor case emptying, a check valve was retrofitted on the case drain line to keep the motor case full of oil. In three and a half days, the following work was completed:

  • Strip down of winch/removal of old hydraulic motor
  • Reassembly of winch/installation of new hydraulic motor
  • Supply and retrofit check valve on motor drain line
  • Spool fibre rope off the winch and re-spool back on under back tension (on review of the winch manual, it was discovered that the rope should have been overwound, not underwound)
  • Installed the winch to our test bed and completed: no-load function/speed checks, observing for any abnormal noise, heat build-up etc; stall test against the brake; dynamic pull test up to proof load (1.25 x SWL); and pull test against the brake up to SWL
  • Removed the winch from our test bed and prepared for shipment
  • Delivered the winch to site

As soon as the winch was delivered, Sparrows mobilised a hydraulic supervisor and inspector to site to complete the commissioning and testing on board the vessel, inclusive of:

  • MPI welds associated with the winch mounting pads
  • Check torque of winch hold down bolts
  • Function test to ensure satisfactory operation

On completion of the scope an MPI report and Report of Thorough Examination were issued

In total, the scope was successfully completed in four days allowing the vessel to commence with their project.


Integrated solution

  • Fault finding and repair


  • Maintenance/servicing/refurbishment
  • Inspection/testing
  • Fluid power/hydraulics.

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Winch repair to support vessel project

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