Intermediate shaft damage and Babbitt white metal bearing of a vessel owned by a reputed shipping company were reported. RA Power Solutions deputed a team of two technicians along with an onsite grinding and polishing machine to Port Lavgan dockyard Ratnagiri India.
The major technical details of the Intermediate shaft are as follows:
| S. NO | Intermediate shaft Details | |
| 1. | Engine Make | Bergen |
| 2. | Engine Model | 15054 |
| 3. | Intermediate shaft Diameter Standard | 280 mm |
| 4. | Intermediate Bearing Width | 275 mm |
| 5. | Place of execution of Intermediate repair | At Port Lavgan dockyard Ratnagiri. |
Inspection of Intermediate shaft and repair planning:
- The intermediate shaft having a standard diameter of 280 mm and bearing width of 275 mm was inspected for dimensions, taper & ovality. Excessive ovality ranging from 0.36 mm to 0.72 mm was observed.
- Due to the failure of Babbitt’s white metal bearing the white metal was badly stuck on the diameter. It was removed by our technicians.
- As a routine inspection, the crack detection test by the MPI method was undertaken. Surface cracks on an entire diameter and bearing width were observed. The cracks were minor.
- The hardness was in general observed within limits and in the range of 182 HB scale (minimum) to 343 HB scale (maximum). Few hardened spots were observed.
- Due to the failure of Babbitt white metal bearing, deep scoring marks were observed on the intermediate shaft diameter.
- The intermediate shaft bearing area was observed to be rough with a surface finish of 0.90 RA value which is observed to be poor.
Action taken by RA Power Solutions for successful repair of the Intermediate Shaft
- The grinding of the intermediate shaft bearing sitting area was undertaken in different steps, as the objective was to remove the ovality and bearing line marks by reducing the intermediate shaft diameter to the minimum.
- After undersizing the diameter by 1.0 mm i.e. 279.00 mm the ovality and damage were still observed. It was decided to undertake further grinding.
- Finally, the diameter was reduced by 1.40 mm, maintaining a final diameter of 278.60 mm.
- The intermediate shaft bearing sitting diameter was polished after grinding.
- The following tolerance was maintained:
- Taper & ovality was maintained within 0.02 mm.
- The surface finish was improved & maintained less than the 0.15 mm RA value.
Grinding of Intermediate Shaft Bearing sitting diameter having no radius:
The onsite repair of the damaged intermediate shaft diameter was a challenge as it didn’t have any radius fillet. The companies based in Europe have an old design and outdated equipment as they take reference of radius fillet to undertake grinding. In this case, RA Power Solutions used equipment that doesn’t take any reference of radius fillet as the machine designed and owned by RA Power Solutions is a replica of a bench-type crankshaft grinding machine. By using this special-purpose machine, the repairs were executed successfully.
We have been regularly executing on site crankshaft repairs and crankshaft grinding in Dubai, Oman, Saudi Arabia, Qatar, Abu Dhabi, Sharjah, Ajman, Umm Al-Quwain, and Fujairah, Bahrain, Kuwait, Iraq, Antigua and Barbuda, Belize, Dominica, Dominican Republic, Grenada, Guyana, Haiti, Jamaica, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Trinidad, and Tobago, etc.
For more details on the crankshaft polishing machine, and main journal polishing please email us at rajshahani@rapowersolutions.com, info@rapowersolutions.com, or call us at +91 9582647131, +91 9810012383.
