Reinforced Polyurethane Foam (R-PUF): Y-HF-M-120
Reinforced Polyurethane Foam (R-PUF): Y-HF-M-120 by Jiangsu Yoke Technology Co.,Ltd. DNV TA certificate TAK0000264.
Inspector Detail
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Common issues
- Seal leakage at rotor vanes leading to internal or external hydraulic oil loss
- Hydraulic oil contamination with water or particulates degrading seal and valve life
- Vane and stator liner wear increasing internal leakage and reducing rudder response speed
- Rudder feedback linkage or transmitter misalignment causing rudder angle indication errors
- Relief valve setting drift allowing pressure loss under load
- Sticking non-return or changeover valves affecting hand/emergency steering changeover
- Foundation or mounting bolt looseness from vibration over time
Inspection checklist
- Check hydraulic oil level, colour and water/particulate content
- Inspect for external oil leakage at rotor shaft seals and pipe connections
- Verify rudder angle indicator reading matches actual rudder position at both hard-over limits
- Test changeover between main and auxiliary/hand steering power units
- Check relief valve setting against approved value
- Inspect mounting bolts and foundation for looseness or cracking
- Test follow-up and non-follow-up steering control response
- Run both power units in turn and confirm equal performance
Service intervals
| Hydraulic oil sampling | every 3 months or per maker's PMS |
| Hydraulic oil change | typically every 2-3 years or on condition, confirm against maker |
| Seal and leakage inspection | annual |
| Relief valve setting check | annual |
| Steering gear function and changeover test | before departure / weekly per SOLAS drill requirement |
Typical wear limits
| Hydraulic oil cleanliness | commonly maintained around ISO 4406 18/16/13 or cleaner for rotary vane steering hydraulics - confirm against maker's spec |
| Rudder carrier bearing clearance | typically a small fraction of a millimetre for this size class and increases with running hours - confirm exact limit against the maker's manual |
Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.
Critical spares
- Rotor/vane seal kit
- Relief valve
- Non-return and changeover valves
- Hydraulic pump shaft seal
- Rudder angle transmitter
- Solenoid control valves
Safety
- High-pressure hydraulic oil injection injury during leak tracing or fitting work
- Unexpected rudder movement during maintenance or testing - isolate control power first
- Confined or poorly ventilated steering gear compartment
- Hot hydraulic oil on running system
Class survey
Steering gear is safety-critical class machinery under SOLAS Ch.II-1; class expects records of the required daily/weekly changeover tests, annual function tests of main and auxiliary gear, and confirmation that rudder angle indication and bridge communication remain correct after any maintenance.
Components & Design
Component data being added…
Technical Data
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Maritime Network →DNV type approval
Verified against the DNV Approval Finder — the certificate below is issued by DNV, not by us.
- Certificate
- TAK0000264
- Approved as
- Insulation Materials for Gas Carriers · Non-metallic Materials
- Certificate holder
- Jiangsu Yoke Technology Co.,Ltd (China)
- Valid until
- 2027-10-30