Diesel Power specialist Royston has successfully carried out the overhaul of turbochargers on two offshore supply vessels (OSVs) operated by Tidewater Marine in the oilfields off the coast of South West Africa. The engineers completed the full overhaul of Napier NA297 turbochargers on the Melton Tide firefighting and offshore support vessel and the success of this work led to more recent service work being undertaken on the Netherland Tide, multi-purpose support vessel.

Two Napier turbocharger installations on the Melton Tide, powered by dual Wartsila 9L26 engines, were serviced at Walvis Bay, Namibia. The work on the two CAT C280-16 engine-powered Netherland Tide involved four turbocharger overhauls while berthed at the Sturrock drydock in Cape Town, South Africa.

In each case,  Royston was responsible for the supply of parts, strip inspection, overhaul and on-site repair of the turbochargers as part of a regular service interval. As part of the work undertaken on both vessels, special crack detection inspections were carried out on the turbine wheels to identify any hairline fractures present.

In addition, digital clock gauges were used to measure blade clearances on the rotor shaft running gear to ensure that Napier OEM specifications were maintained. Where necessary, adjustments to the extremely tight clearance specifications were made using special shims.

Royston has made a substantial investment in the bespoke overhaul tool kits, spares and equipment that are needed to ensure that all Napier turbocharger repairs, rotor balancing and servicing are carried out in complete compliance with required specifications and technical standards.