Crankpin & Main Bearing Journal on a Bergen BRG/M8 Crankshaft

In this case study, we delve into a challenging scenario faced by a large marine vessel, which encountered problems shortly after a long refit period and a regeneration program.

With alarm issues triggering concerns, the client sought the expertise of a specialist engine overhaul provider. Their assessment revealed that rectification was necessary for the machined crankpin journal.

Seeking an accurate evaluation, the client came to us for our marine engine and in-situ crankshaft repair expertise. Our role involved re-confirming their initial findings, conducting a comprehensive assessment, and providing recommendations for rectification. Read on to discover how our commitment to delivering top-quality services got this vessel's engine ship shape again.

Inspection Findings: Crankpin & Main Bearing Journal

During our inspection of the #5 crankpin journal, our expert team noted several factors rendering it outside the required OEM specification. These included but were not limited to a flatness below 90% and high areas on the outer edges, with a dip toward the centre of the crankpin.

We also observed issues with the fillet radii and undercut intersection, an incorrect blending of the oil hole radius with the diameter of the crankpin journal, and visible marks from the previous superfinishing process. In addition, we inspected main bearing journals #5 and #6, discovering significant corrosion on main bearing journal #5, requiring grinding to the next undersize bearing increment. However, only some small areas of decay were found on the main bearing journal #6, which we rectified by machine polishing.

Our Solution

Based on the inspection findings, our team adapted our high-end bespoke equipment to meet the vessel's needs and quickly mobilised back to the vessel to undertake the crankshaft repairs and main bearing journal repair works.

With our expertise and knowledge base, we accurately machined the crankpin journal (270mm), achieving a further 1.00mm undersize and restoring all fillet and oil hole radii, flatness, taper, and ovality to OEM specification. Additionally, we re-ground the main bearing journal (290mm) to the first undersize of -1.0mm in diameter, restoring all areas to OEM specification, including parallelism of the crankpin to the shaft axis. Our focus on delivering top-notch service is reflected in our quality checks, which showed final flatness checks at 95% and surface finish at 0.23 Ra UM.

Positive Results

Our commitment to quality is reflected in our efficient turnaround time and prompt response, with all works being completed on time and signed off by the client and specialist engine overhaul company - resulting in a successful result.

With expertise in industrial onsite machining repair and our advanced, custom-made, and mobile equipment enabled our expert engineers to identify these issues promptly and deliver solutions that significantly reduced the vessel's downtime while saving costs.

We minimised the vessel's downtime, allowing it to resume operations quickly. At the same time, our focus on cost-effective solutions resulted in significant cost savings for the client by rectifying the issues with the crankpin and main bearing journals.

International Onsite Crankshaft Repairs by In-Situ Machining Solutions

At In-Situ Machining Solutions, our commitment to delivering high-quality offshore marine repair is second to none. As an industry-leading provider of industrial machinery repair, we have a great deal of experience with offshore and marine repair solutions, as explained in our other case studies, such as:

In summary, we successfully identified and rectified issues with the HMS Protector's engine, resulting in reduced downtime and significant cost savings for the client. Our dedication to continuous training and development ensures that our highly skilled engineers deliver top-notch service.

We invite you to experience the benefits of In-Situ services firsthand. Our adaptable onsite machining service adaptability which enables us to serve clients worldwide. Contact us today for a bespoke solution that meets your requirements.

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