As of January 2007 all new-built vessels for service in US waters are required to be powered with engines that meet the US Environmental Protection Agency's Tier 2 emission standards. It has been a significant engineering and logistics challenge for the nation?s engine manufacturers to meet these deadlines. Cummins (CMI)
Marine was able to meet the deadline and is shipping Tier 2 engines in the full horsepower range.
Although Tier 2 is a requirement for all new vessels, at Olympic Tug and Barge the owners, Harley Marine Services, have shown leadership by installing a pair of Tier 2 compliant engines in their 1970-built tug Lela Joy. This will make her one of the most environmentally progressive vessels on the Pacific coast. A pair of aging two-cycle engines were pulled from the 77.5 by 25.4-foot tug and replaced with a pair of Cummins' new QSK38-M engines. The new engines each produce 1200 continuous duty horsepower at 1800 RPM. The QSK38 engine builds on the recognized success of the V12 38-liter KV Series engines. The Cummins QSK38 has taken the legendary durability of the base engine and enhanced it with the proven technology of the Cummins Quantum System electronics and Modular Common Rail fuel system also found on its Tier 2 QSK50 and QSK60 engines. This performance and technology upgrade ensures not only Tier 2 emissions compliance but also quieter operation, better fuel economy, smoother power delivery and better idle stability. The modular common rail fuel system features a simplified design that provides constant high injection pressure regardless of engine speed or load conditions. Benefits include significantly reduced noise and vibration for quiet operation, idle stability and improved low-end torque.
Among other design improvements of the new engines, the triple-wall water-cooled exhaust manifold features an air gap between exhaust gas and jacket water to maintain thermal efficiency while cooling engine surface temperatures. Design is a fabricated single piece construction that eliminates potential exhaust leakage.
"Vessel operators who have known the original KTA38 over the years as a highly reliable and cost effective engine will be reassured to know that the new QSK38 shares 70% of its parts with its antecedent. Harley Marine Services joins a number of leading marine operators in the US that are installing the new IMO and EPA Tier 2 certified Cummins engines.
In addition to the repower, the Lela Joy underwent a major refit at Portland?s Diversified Marine Inc. This included extensive steel replacement and other upgrades.