The new 820 mm-bore low-speed marine engines developed by Wärtsilä Corporation are proving to be successful in the market. With the second engine passing its factory acceptance test, orders booked by Wärtsilä's licensed engine builders have amounted to 129 engines with an aggregate power of 4415 MW (6.0 million bhp).
The engines are being installed in panamax-sized container ships, large tankers such as VLCCs (Very Large Crude Oil Carriers), and VLOCs (Very Large Ore Carriers) being constructed at shipyards in South Korea, China and Germany.
The 129 engines so far ordered comprise 74 engines of the RT-flex82C type, 29 of the RT-flex82T type, 22 of the RTA82C type and four of the RTA82T type.
The first two engines, both eight-cylinder Wärtsilä RTA82C engines, have passed their factory acceptance tests at Hyundai Heavy Industries Co Ltd in . The eight-cylinder RTA82C engines have maximum continuous outputs of 36,160 kW at 102 rpm. They are being installed in 4300 TEU container ships.
Four engine types of the same 820 mm bore, the RT-flex82C, RTA82C, RT-flex82T and RTA82T types, have been developed by Wärtsilä. The engines were introduced to the market in the end of 2005.
The four engine types have been developed on the basis of a common platform and sharing as many parts as possible to bring benefits of rationalization in the design and manufacturing, lowering manufacturing costs, and rationalizing also spare parts stocks.
The new Wärtsilä RT-flex82C and RT-flex82T engine types bring the benefits of both the electronically-controlled RT-flex common-rail system and up-to-date parameters to deliver optimum propulsion plants for the envisaged ship types.
The -'C' versions are intended to be ideal prime movers for container ships of panamax size with capacities up to around 5000 TEU and service speeds typically of about 24 knots. They will have a stroke of 2646 mm and will be available with six to twelve cylinders to cover a power range of 21,720 kW to 54,240 kW at 87 to 102 rev/min.
The -'T' versions will have a stroke of 3375 mm to suit the optimum shaft speeds for the propulsion of large tankers, VLCCs and ULCCs of 200,000 dwt to more than 350,000 dwt, as well as very large bulk, ore and combination carriers. The engines will be built with six to nine cylinders to cover a power range of 21,720 kW to 40,680 kW at 68 to 80 rev/min.
A particular feature of these 820 mm-bore engines is their extended layout field where the power/speed ranges of the engines are extended to higher speeds at ratings R1+ and R2+ with the same powers as the usual R1 and R2 ratings respectively. The extended fields offer widened flexibility to select the most efficient propeller speed for lowest daily fuel consumption. This widened layout flexibility is already proving beneficial in ship projects.
The fact that the majority of the new 820 mm-bore engines ordered are of the RT-flex types - 103 out of a total of 129 engines - emphasizes the popularity of Wärtsilä's RT-flex electronically-controlled common-rail low-speed marine engines. At the end of May 2008, a total of 678 RT-flex engines aggregating 21,880 MW had been ordered. This total includes all sizes of RT-flex engines in the program, from 500 to 960 mm bore.