ISO-socket, double, Type: D92B
The MacGregor D92B is a double‑socket ISO‑rated mooring winch that can be equipped with hydraulic or electric drive and up to three interchangeable drums, delivering up to 500 t brake holding capacity for heavy anchoring and offshore mooring applications.
Inspector Detail
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Common issues
- Brake band lining wear reducing holding capacity below the rated value
- Hydraulic leaks at swivel joints, motor seals or valve blocks
- Clutch (drum disengagement) slipping or failing to engage/disengage cleanly
- Wire rope/drum spooling misalignment causing uneven layering and rope damage
- Load cell or tension-monitoring sensor drift giving inaccurate line tension readings
- Corrosion of the brake drum surface affecting braking consistency
- Control system faults on the local or remote station, particularly on electric-drive variants
- Gearbox bearing wear from sustained high-load mooring operations
Inspection checklist
- Visual check of brake band lining thickness and drum surface condition
- Function test of brake apply/release and emergency release
- Verify brake holding capacity against the last class-witnessed render test record
- Check hydraulic oil level, condition and for external leaks
- Inspect clutch engagement/disengagement and drum freewheel operation
- Check mooring wire/rope condition and correct spooling on the drum
- Test local and remote control stations, including emergency stop
- Verify load monitoring/tension display against a known reference if fitted
- Check foundation bolts and structural mounting for looseness or cracking
- Test warping head/capstan operation if fitted
Service intervals
| Brake band lining inspection | annually, or per maker/class requirement |
| Hydraulic oil sampling / analysis | every 6-12 months |
| Brake holding capacity (render) test | at each class survey cycle, typically 5-year renewal with intermediate checks |
| Gearbox oil inspection/change | inspection annually, change per maker interval (often 2-5 years) |
| Wire rope inspection and lubrication | monthly to quarterly depending on trading pattern |
| Load cell/tension sensor calibration | annually |
Typical wear limits
| Brake band lining thickness | renew at roughly 50% of new thickness or below the maker's stated minimum - confirm against the maker's manual |
| Brake holding capacity | must not fall below the rated value confirmed at class-witnessed render test, commonly required at a set percentage of the mooring line's minimum breaking load |
| Drum/rope groove wear | assessed visually for grooving that could damage the wire rope; no universal dimension applies |
Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.
Critical spares
- Brake band lining/friction material
- Hydraulic motor seal kit
- Clutch friction plates/lining
- Hydraulic control valve or solenoid assembly
- Load pin/load cell sensor
- Gearbox bearings
- Mooring wire (drum-length replacement)
Safety
- Stored energy in a loaded mooring line - snap-back zones must be respected during operation and maintenance
- Never test or adjust the brake with personnel in the bight or snap-back zone
- Hydraulic system under pressure - isolate before opening lines or components
- Uncontrolled drum release under load is a crush/struck-by hazard
- Brake holding capacity below the rated value is a mooring-line-parting and personnel-injury risk
Class survey
Brake holding capacity is typically verified by a class-witnessed render/no-render test at survey (commonly linked to the 5-year renewal cycle), checked against a percentage of the mooring line's minimum breaking load. Records of brake tests and lining renewals should be retained for survey.
Components & Design
Component data being added…
Technical Data
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Common failures & inspection points
Conduct brake rendering test using Brake Testing Kit or torque spanner method. Accept only if PRIMARY brake holds min. 60% of ship design MBL. Test after every brake lining renewal, before delivery, within 30 days takeover, and annually. Adjust lining if wear exceeds 40% residual thickness.
Measure link diameter at wear points - maximum 12% reduction allowed by class rules. Inspect for cracks, distortion, corrosion pitting, especially under gypsy where crevice corrosion occurs. Monitor for abrasion from rocks/sand. In saltwater, check galvanized steel for oxidation; in stainless, examine for crevice attack in oxygen-starved spots.
Check hydraulic lines and piping monthly for leaks, tightness, proper valve function. Inspect hydraulic fluid condition (contamination, moisture, oil breakdown). Oil, moisture, or heavy rust on brake lining/drum can reduce holding capacity up to 75%. Temperature monitoring on hydraulic pipelines indicates lubrication issues.
Inspect brake lining thickness regularly - renewal required when residual thickness drops below 50-60% of original (e.g., 8mm original -> replace at 4-5mm). Check for discoloration, scorching, unevenness, rough spots. Replace upper AND lower linings simultaneously. On non-tank vessels, renew at every drydock regardless of condition.
Test hydraulic-operated chain stopper self-locking release capability under FULL DESIGN LOAD. Verify proper engagement/disengagement cycles. For Pusnes EFCS: check eccentric mechanism for wear, hydraulic pressure (motor protection integration). For Hatlapa roller stopper: inspect roller wear, high-pressure hydraulic motor function. Examine for leaks, cracks, corrosion on stopper pins/bushings.
Examine foundation bolts, welds, support frame before and after heavy anchoring/mooring operations for stress cracks, corrosion pitting, galvanic corrosion at dissimilar metal joints (fairlead/deck interface). Verify no settlement or deformation. In rough weather operations, monitor for fatigue cracking under excessive loads. Apply protective coatings where needed (zinc-rich primer + topcoat).
Type-general inspection and maintenance points for this equipment category — not model-specific.
Service & Maintenance
Brake lining inspection every 6 months. Gear oil change every 2 years. Wildcat measurement during docking. Motor insulation test annually.
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