Hospital Ship USNS Mercy Gets Turbocharger Retrofit


Published Mar 24, 2020 1:08 PM by MSHS

Motor-Services Hugo Stamp, Inc. (MSHS) was contracted to retrofit the twin MAN NR26/98 turbochargers on three separate MAN 12ASV25/30 auxiliary diesel generator (ADG) engines aboard the USNS Mercy hospital ship with MAN TCR18-42145 turbochargers.

The ADG engines and their turbochargers were built in 1984 and commissioned in 1985. Nearing the end of their life cycle and becoming obsolete, the availability of spare parts for the MAN NR26/28 turbochargers became increasingly unreliable. Another issue was the publishing of a MAN Safety Alert Bulletin (ASB20130218) stating that NR turbochargers with gray cast iron castings do not ensure full containment safety in the case of rotor failures. With the goal for this ship to continue providing services for at least two more decades and to improve reliability and seaworthiness as well, a major upgrade was necessary.

The project required detailed installation drawings, bill of materials, test procedures, and the engineering and manufacturing of the complete adapter kits to integrate the new turbochargers into the existing engine room environment. The new insulation had to fulfill the latest IMO requirements. A weights and moments calculation for the new turbochargers was required for the ship’s stability analysis.

The scope of work also included the installation of all components, sensors, and cables as well as upgrading the alarm, monitoring and safety system.

Project details

Before the actual equipment upgrade could begin, MSHS was required to submit and receive ABS and USCG approval for all technical data, drawings, and test procedures. Every aspect had to meet IMO- SOLAS requirements. Due to the stringent requirements, the complete process took 15 months and included methodical planning, engineering efforts, vendor qualifying, and specific parts orders. The attention to detail finally paid off with the approval coming from all the required regulatory bodies.

To accommodate the new turbochargers, MSHS Metalock Engineering USASM (MME) modified the existing turbocharger foundations. MSHS service engineers installed the new MAN TCR18-42145 turbochargers, additional sensors, and cables, and updated the alarm, monitoring, and safety system. During the intensive commissioning program, all turbochargers were tested at various load stages, including a 110 percent load test, which was concluded successfully with the final class approval received.

MSHS’ post-retrofit engineering efforts included updating the drawings and bill of material to the as-built status. The team also compiled installation service reports, approval certificates, and commissioning and compliance reports.

The new turbochargers are expected to yield fuel savings, bring down peak operating temperatures, improve the overall efficiency, and provide reliable service for many years to come.

This article is sponsored by MSHS and MME. MSHS is a provider of turnkey solutions for the maritime and stationary power industries. MSHS specializes in the testing, maintenance, repair and overhaul of diesel engines, turbochargers, waterjets, filtration, separation systems, safety, control, and automation systems. MME is recognized worldwide for offering emergency On Site / In Situ repair services. For a complete overview, visit www.mshs.com or call +1 954 763-3660.

The opinions expressed herein are the author's and not necessarily those of The Maritime Executive.