The non-operation of two auxiliary engines stranded the vessel. Considering the urgency of the situation, RA Power Solutions deputed two technicians along with a specially designed onsite crankshaft grinding machine capable of grinding crankpins with small diameters and narrow widths.

In the case of the MAK 6M20 auxiliary engine, the standard diameter of the crankpin is only 152.00 mm, with a bearing width of 71 mm. The design of our onsite crankshaft grinding machine is such that it can be mounted on the crankpin diameter through the inspection window, and grinding is executed in situ.

The details of the engine are as follows:

Upon arrival on board the vessel, our technicians conducted an initial inspection of all crankpins. They found excessive ovality in all six crankpins of the MAK 6M20 engine.

We have provided a copy of the preliminary dimensional inspection report below.

All other parameters, including hardness, MPI, and deflection, were within acceptable limits. We jointly decided to grind all the crankpins, and RA Power Solutions machined them to a final size of 151.00 mm (1.00 mm undersize) as per the above dimensions.

During the stay of our technicians on board the vessel, the crankshaft of Auxiliary Engine #02 was also inspected. We detected excessive ovality showing the same pattern observed in the crankshaft of Auxiliary Engine 01.

The preliminary dimensional inspection report is provided below:

SIZE OF CR Pins Before Grinding of A/E 02
	A	Aa	C	Cc	B	Bb	Min	STD	Ovality
CR-1	151.73	151.85	151.74	151.84	151.75	151.82	151.73	152.00	0.27 MM
CR-2	151.73	151.85	151.72	151.83	151.70	151.81	151.7	152.00	0.30 MM
CR-3	151.72	151.85	151.71	151.84	151.69	151.83	151.69	152.00	0.31 MM
CR-4	151.75	151.85	151.72	151.84	151.73	151.86	151.72	152.00	0.28 MM
CR-5	151.73	151.84	151.69	151.82	151.70	151.84	151.69	152.00	0.31 MM
CR-6	151.73	151.92	151.72	151.89	151.75	151.84	151.72	152.00	0.28 MM

Our technicians ground this crankshaft and maintained the following dimensions. They successfully commissioned both engines in their presence.

SIZE OF CR Pins After Grinding A/E 02
	A	Aa	C	Cc	B	Bb	Min	Max	Ovality
CR-1	151.00	150.99	150.99	150.98	150.99	151	150.98	151.00	0.02 MM
CR-2	151.00	150.99	150.99	150.98	151.00	150.98	150.98	151.00 0.02 MM	0.02 MM
CR-3	151.00	150.99	150.98	150.98	150.99	151.00	150.98	151.00	0.02 MM
CR-4	151.00	150.99	150.98	150.99	150.99	151.00	150.98	151.00	0.02 MM
CR-5	151.00	150.99	150.98	150.98	150.99	151.00	150.98	151.00	0.02 MM
CR-6	151.00	150.99	150.98	150.98	150.99	151.00	150.98	151.00	0.02 MM

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