The Mack Attack is a recently launched Viking 48 Convertible, a flybridge model that looks no different from other Vikings in the 48-foot class, but it has a secret. Belowdecks beats a heart of Swedish gold in the form of high-performance Scania DI16 diesel engines. The boat, a collaboration between Scania, Mack Boring—the largest Scania distributor in the U.S.—and Viking Yacht Company, is the test bed for these 16-liter, 1,150-hp V8s that are new to the U.S. market.
To most recreational boaters in the U.S., Scania might not be a household word, but in the rest of the world its engines are legendary. The company has been in business for 133 years and builds more than 100,000 diesel engines annually. The majority powers Scania trucks, buses and industrial equipment; the rest serve in a wide range of marine applications. The company’s long presence in commercial vessels in the U.S. has earned the brand a reputation for economy of operation, longevity under demanding conditions, and ease of maintenance and repair. But building engines for use in pleasure boats like the Viking is another ball game. Two years ago, Scania and Mack Boring built a Viking 46 Billfish christened Mack 900 with a pair of the then new DI13 900-hp 6-cylinder engines lauded for an impressive power-to-weight ratio and performance curve. I was there and the engines were light, fast, quieter than the competition and produced no visible smoke. After a year of testing, Viking added the DI13 to its power option list. So, I was eager to try out the new V8s.
What many boaters might not realize is that Scania engines were powering pleasure boats in the U.S. two decades ago but under a different banner.
“As a distributor for Yanmar diesels, we became acquainted with Scania in 2004,” says Pat McGovern, president of Mack Boring. “At the time, Scania was manufacturing Yanmar’s higher horsepower engines under a partnership agreement, but they were branded as Yanmar. We called them Scanmars. They were great engines, and gave us the opportunity to experience Scania’s corporate culture and the quality and reliability they build into their products.”
The partnership was a casualty of the 2008 recession, but Mack Boring began representing Scania in the U.S. commercial marine market. More recently, with the introduction of the DI13 and now the DI16 pleasure craft engines, things have come full circle. For boat builders offering Scania power, the brand is an upgrade. For example, the upcharge for Scania 900 hp DI13s over the MAN 850s in the Viking 46 Billfish is about $15,000. Scania calls its iron the “bespoke” power choice, an engine for a specific customer.
“Scania engines provide a number of benefits over the competition,” said Alberto Alcalá, U.S. senior sales manager at Scania. He was aboard the Viking for my sea trial. “They are lighter, have a smaller footprint in the engine room, and offer the highest power-to-weight ratio in their class. They have a longer period between service intervals and are easier to work on when necessary. They offer exceptional acceleration, greater fuel economy, and are among the most environmentally friendly diesels in the world because they produce little or no smoke, which is caused by unburned fuel.”
The DI series engines are based on Scania’s acclaimed commercial marine diesels, which utilize unit injection and a simple wastegate turbocharger, a reliable method of feeding fuel into the combustion chambers of engines with lower horsepower ratings and longer duty cycles. On recreational boats like the Viking the horsepower demands are greater and the duty cycles shorter, so the engines are equipped with a high-pressure common-rail injector system that provides multiple injection pulses to better control combustion, reduce particulate matter (smoke) and produce more power output.
The cylinder design is one of the reasons for the efficiency and longevity of these engines. Typical diesels incorporate a hanging cylinder supported at the top of the block. Scania utilizes a standing cylinder, where the liners are supported at the base on a ledge deep inside the engine block. This allows the coolant jackets to extend closer to the combustion chamber, reducing operating temperature, improving fuel burn and providing room for the addition of a “saver ring” at the very top of the combustion chamber.
The saver ring has a slightly smaller inner diameter than the cylinder wall, so when the piston rises, if there is any carbon buildup on its outer edge it simply flakes off. This helps the piston rings better control oil, keeping it in the pan where it belongs. It also improves the combustion event, and reduces cylinder wall scoring, which increases cylinder life while extending the time required between oil changes.
The saver ring is held in place by the cylinder head, but instead of having a single head for an entire bank of cylinders, Scania utilizes individual heads for each cylinder. That means you can work on the top end of the engine without hoists and repair or replace a single cylinder liner if needed. The heads, cylinders and pistons are common between various engines in a series, which is one of the reasons Scania diesels have 30 percent parts commonality. This improves parts availability across the board. Scania’s parts warehouse is in close proximity to UPS headquarters in Louisville, Kentucky, which allows for overnight delivery of parts shipments anywhere in the country. The warehouse maintains a stock of 98 percent of the parts for Scania engines.
The engine blocks are constructed of compacted graphite iron rather than the more common gray iron. The material is heavier but considerably stronger, and when the milling process is completed it weighs less than a gray iron block. Because the Scania is lighter, stronger and less prone to deformation under heavy loads, it has longevity and a high power-to-weight ratio. The engines are easy to service and work on, making them great for owners who like to get oil on their hands from time to time. Scania, through its distributor network, maintains dealers throughout the U.S. and will assist owners by routing the servicing dealer that can get to your vessel the fastest. It’s part of the Scania handshake program that starts with the registration of your engine and an introductory phone call from the nearest dealer.
Sitting behind the helm on the flybridge of the Viking 48C Mack Attack was an experience for me. We departed the Canon Club in Cape May, New Jersey, and ran offshore a few miles. From a dead stop, when the captain put the hammer down the acceleration was exhilarating, pushing me back in the seat. A look over my shoulder confirmed that the blastoff was smoke free as the boat pulled hard to its top end of 38 knots. At a fast cruise of 1900 rpm the boat made 30 knots, yet the engines were reserved and quiet, allowing for easy conversation in the salon and cockpit while burning a total of 82 gph. At trolling speed, the decibel level was so low I almost forget the engines were running.
There’s a lot to Scania’s new DI series engines that set them apart from the competition and make them a serious consideration for those ordering new boats or repowering existing vessels.
This article was originally published in the November 2024 issue.
