Marine Diesel Engines - Diesel Alternatives
The Miami Boat Show
This winter, we blew our Diesel Power expense budget by chasing bikinis and checking out the latest diesel engines in sunny Miami. Going into the show, we knew very little about the engines that find their way into diesel-powered ships and speedboats. After a few days at the docks and a few engine-room tours, we know a little more, but we've still got a lot to learn.
For the most part, marinized diesels-diesels that have been modified for use in marine applications-are engines that were designed for use in road-going vehicles. But the life of an engine is a lot tougher in a boat than in your typical diesel-powered pickup. Typically, a marine diesel engine begins as a heavy-duty version of a road-going diesel engine (let's say a Cummins 5.9L, for example). It's then fitted with a new intake, exhaust, and cooling system so it can be packaged inside the hull of a ship. Engines designed for public roads have to meet much more stringent emissions standards than boats do, so marinized diesels have far less emissions equipment. These lower emissions standards mean that you will still find a number of mechanical- and unit-injection diesels in boats, while common-rail injection is just coming into popularity. It also means that horsepower and torque numbers can be significantly higher.
We weren't expecting to see a 6.6L Duramax engine marinized so soon, but Exergy Engineering and Peninsular Engines brought out this 350hp, LLY-based engine that'd be perfect for high-powered commercial or pleasure boats. To eliminate the corrosion caused by salt-water use, the double-walled stainless steel headers, water-cooled Garrett turbine housing, and air-to-water intercooler all work with engine coolant that is routed into heat-exchanger tanks mounted on the front of the engine. From there, the engine's heat is cooled by water drawn up through the hull of the boat. We were particularly impressed that the engine was fitted with a number of production-truck pieces like the Hummer H1 Alpha oil pan. It wasn't rocket science, but these guys were able to take advantage of the compact packaging and oil-control advantages designed into the pan for off-road use.