The US Coast Guard (USCG) has selected the 28/33 STC engines by MAN as main propulsion for its new Offshore Patrol Cutter (OPC) program.
The program is the replacement platform for the 13 ‘Famous’ class and 14 ‘Reliance’ class cutter vessels, making the order the largest vessel p[ds_preview]rocurement order in the Coast Guard’s history.
Each of the new 110 m long cutters will be powered by two MAN 16V28/33D STC engines, developing 7,280 kW each @ 1,000 rpm. FME will produce and test the engines at its Beloit, Wisconsin plant, while Eastern Shipbuilding Group, based in Panama City, Florida, will design and construct the OPC ships. Initially, the USCG has ordered nine ships with plans to ultimately produce 25. Delivery of the first ship of the class to the USCG is scheduled for 2021.
According to MAN the 28/33D STC engine offers compact power that sets itself apart with a high power-to-weight ratio. All engines are fully compliant with current environmental standards, producing NOx emissions that fulfil IMO Tier II (+ Tier III with Selective Catalytic Reduction) and EPA Tier 2 regulations. Maintenance costs and servicing downtime are kept low thanks to high engine availability.
Operation of STC
The sequential turbocharging (STC) concept operates with twin MAN TCA33 axial turbochargers – specially developed for the MAN 28/33D STC engine – with the option to switch the second turbocharger off at low engine loads. Using the STC system allows the engine to be operated at its optimum operating point over the whole applicable load range.
High efficiency at full and part loads results in a substantial air surplus, thorough combustion without residues, and low thermal stress of combustion-chamber components the manufacturer stated.
STC also delivers decreased smoke emissions, low vibration and reduced part-load fuel consumption the company added.
