Aberthaw Fisher - main bearing transplants
Having discovered cracks in one of the main engine bedplate bearing pockets of the MV Aberthaw Fisher, the
then owners James Fisher & Sons plc asked Metalock Engineering UK, Coventry if a repair was possible due
to a new bedplate not being available for at least 5 months. This would have put the vessel out of commission
for an unacceptable period.
Metalock engineers surveyed the damage and submitted proposals for repair which after some discussions
and modifications were accepted by Lloyd’s Register of Shipping, provided that subsequently they carried out
regular inspections. Five years on the vessel, under new ownership, was still fully operational as a diamond
mining vessel for Benguela Operations(PTY) Ltd in South Africa.
To effect the repair the damaged bearing pocket was cut out by chain drilling, machining and hand fitting to
accept a steel insert. To provide maximum integrity the insert was machined from a single solid piece of steel
to precisely match the shape formed in the bedplate, then fitted to ensure full contact on mating faces. It was
secured into the bedplate using the well established Metalock cold stitching keys and studs technique.
Once the new bearing pocket was fully stitched into place, a portable milling machine was set up on the
bedplate and the top of the insert machined flush to the joint face. At the same setting, the bearing cap joint
faces were machined to size. With the new bearing cap fitted, a boring bar was optically aligned true the
centreline of the undamaged bearing pockets and the new pocket line-bored to the correct diameter.
The repairs were completed and full engine tests including a two hour long full power trial were conducted.
Following these successful trials the MV Aberthaw Fisher was returned to service and after a series of regular
inspections by Lloyd’s, eventually regained its full classification.
To effect the repair, the damaged pocket was cut out by
chain drilling, machining and hand fitting, to accept a steel
insert machined from a single solid piece of steel to
precisely fit the shape formed in the bedplate