BEARING ALIGNMENT RESTORED IN-PLACE
Misaligned or worn bearing housings cause catastrophic crankshaft and bearing failures if left uncorrected. Conventional repair means complete engine disassembly, crankshaft removal, and workshop re-machining. That is weeks of downtime and serious cost.
OSM International's portable line boring equipment allows precision re-boring of main bearing saddles and associated bearing housings directly in the engine room, with the engine in place. Stern tube and rudder bores are line-bored with the relevant shaft withdrawn, on-site or in drydock. Our CNC-controlled boring bars achieve alignment tolerances of ±0.01mm across bore lengths exceeding 10 meters.
Every line boring job is completed with full dimensional documentation and a certified inspection report, accepted by DNV, Lloyd's Register, ABS, Bureau Veritas, NK, and RINA.
Applications
- Main bearing saddle restoration and alignment
- Stern tube bearing re-boring
- Rudder pintle and gudgeon bearing seats
- Camshaft bearing housing re-bore
- Connecting rod big-end bore restoration
- Crosshead pin bearing alignment
- A-frame and bedplate structure bores
- Pump and compressor bearing housings
Technical Specification
Bore diameter range
50-2,500mm
Alignment tolerance
±0.01mm
Roundness tolerance
±0.008mm
Bore length capability
up to 12,000mm
Drive system
CNC electric / pneumatic
Report acceptance
DNV · LR · ABS · BV · NK · RINA
HOW WE WORK
4-STEP PROCESS
01
Alignment Survey
Optical or laser alignment of the bore centerline. Measurement of all bearing clearances and housing dimensions. Identification of wear patterns and required metal removal.
02
Boring Bar Installation
Precision mounting of portable CNC boring bar on the engine frame. Alignment to the bore centerline within ±0.005mm. Cutting tool selection based on bore material and surface finish requirement.
03
Precision Boring
Computer-controlled boring pass to final diameter. Continuous measurement and adjustment during machining. Single-point or multi-point boring depending on bore configuration.
04
Inspection & Report
Final bore diameter and roundness measurement. Alignment verification to ±0.01mm. Certified inspection report with full dimensional data accepted by classification societies.
PROJECT GALLERY
WORK PHOTOGRAPHY
COMMON QUESTIONS
LINE BORING, ANSWERED
What is line boring on a ship?
Line boring re-machines main bearing saddles, stern tube bores, or other aligned bearing housings back to their original diameter and centerline after wear. A portable boring bar mounts across all saddles and machines them in a single continuous pass, restoring crankshaft alignment and bearing clearances without removing the engine or crankshaft.
Can line boring be done without drydocking the vessel?
Yes. OSM International's portable boring bar mounts directly to the engine frame or bearing housing structure in the engine room, allowing full precision line boring at the dock, at anchorage, or at berth. No drydock or engine extraction is required. We achieve alignment tolerances of ±0.01mm in field conditions.
What bore diameters and lengths can you machine?
Our portable equipment covers bore diameters of 50-2,500mm and bore lengths up to 12,000mm. That spans small auxiliary engine bearing saddles, large two-stroke main engine housings, and full stern tube assemblies. Contact us at +1.800.903.1509 to confirm your specific configuration.
Are line boring inspection reports accepted by classification societies?
Yes. All dimensional inspection reports produced by OSM International are accepted by DNV, Lloyd's Register, ABS, Bureau Veritas, NK (ClassNK), and RINA. Reports include full bore diameter measurements, alignment data, roundness readings, and supporting material documentation.
How long does line boring take?
Most line boring jobs are completed in 1 to 4 days on site, depending on the number of bearing saddles and the bore length. We mobilize within 24 to 48 hours of your call, so a typical main-bearing realignment is back in service within days, with no drydock.
GET STARTED
REQUEST LINE BORING
Tell us about the bore, engine type, and vessel location. We respond within 2 hours with a mobilization plan.
24/7 EMERGENCY LINE
REQUEST SERVICE
We respond within 2 hours. Emergency? Call +1.800.903.1509