Hydraulic retrofit for aft starboard capstan on diving support / well intervention vessel

Retrofitting new hydraulic equipment to the system provided a cost-effective solution


  • Redundant / obsolete equipment removed from the system
  • Cost-effective solution
  • Reduced down-time with work completed in-between port calls
  • More efficient than replacing the entire system.


  • The client came to us with a work scope for a hydraulic retrofit as we've completed a variety of hydraulic activity for them over the past 10 years
  • The anchor winch / capstan systems use a common hydraulic power unit (HPU). With the anchor winch decommissioned, a large part of the hydraulic system was redundant. All redundant hydraulic components were to be removed
  • Due to the age of the system (mid 1980s), a large part of the hydraulic system was obsolete
  • Budget constraints due to market conditions.


  • During a scheduled vessel stop in Aberdeen Harbour, we mobilised a hydraulic supervisor to survey the system with a view to; confirming the as-built status of the hydraulic system and witness function testing of the capstans to fault-find the reported historical operational issues
  • On completion of the survey, a hydraulic review of the system was carried out to determine which components required replacement due to obsolescence / performance issues (or both) and which components required removal due to being redundant (part of the anchor winch system). The following scope of work was recommended to the client:
    • Replace pbsolete A4V250 pump with modern equivalent A4VG250
    • Due to differences between the A4V250 and A4VG250 pump A&B port interface, a custom manifold was to be designed and manufactured to re-use the existing hot oil strip manifold (close-coupled to the pump)
    • Replace cartridge valves in the hot oil strip manifold
    • Due to differences between the A4V250 and A4VG250 pump, retrofit new external boost filter
    • Remove the hydraulic control / brake release manifolds and send to our Aberdeen workshops for strip down, inspection, clean-up, replacement of valves / blank-off redundant and testing
    • Replace obsolete 4TH8 hydraulic joystick with modern equivalent 4TH6
    • Replace obsolete 4WEH32...NZ5L DCV with modern equivalent 4WEH32 DCV with NG32 blanking plate
    • Replace obsolete Viking MK63-16300 motor with modern equivalent MK64-16300
  • On agreeing the scope of work with the client, all parts were ordered and kept in stock ready for destruct / installation to commence during the next scheduled vessel stop in Aberdeen
  • Revised hydraulic schematic and parts list completed
  • Destruct, installation and commissioning procedures completed
  • Working together with the vessel crew, the retrofit was completed in two phases in-between port calls:
    • Destruct / installation
    • Commissioning


Integrated solutions

  • Fault finding and repair
  • Hydraulic system management

Capabilities / services

  • Multi-discipline engineering / design
  • Maintenance / servicing / refurbishment
  • Inspection / testing / rope access
  • Fluid power / hydraulics
  • Site surveys
  • Training / coaching

Equipment rental

  • Rigging / lifting equipment
  • Mechanical handling equipment
  • Spare parts / components.
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