Here’s a riddle for you—if it’s said that diesel has traditionally been the fuel of the maritime industry, why aren’t there more diesel outboards out there? As New Atlas shares, now with the production of the 50hp Yanmar Dtorque 111 turbo-diesel getting underway, arguably the first widespread diesel outboard engine will be hitting the market.
Diesel outboard predecessors have hazarded tried their luck in the past, including attempts by Yanmar itself, but that was a time in the past. With the stack of benefits that come with the new German-designed Neander-Shark engine, pitting this against traditional gas outboard engines is nothing if not cause for excitement.
Here’s how they compare: the Yanmar Dtorque 111 is lighter and more densely constructed than similar capacity gas engines. A lack of vibration in the two-counter-rotating crankshaft design means it doesn’t need the heavier vibration-absorbing clout of a traditional diesel. It runs smoother, has double the engine life at an expected lifespan of over 10,000 hours, and puts out less toxic emissions. At full throttle and full loading, it typically burns less than 3.2 gallons of fuel per hour—which is half the amount of gasoline in similar-performing outboards. And the Dtorque 111, incidentally named for its remarkable low rpm torque (with 111 Nm on offer at 2,500 rpm), can bring a boat up to plane even faster. This is before bringing the safety and availability benefits of diesel fuel into the discussion.
Granted, it’s not all fun and games. Pioneering non-traditional technology can be an edgy business, but it’s a path already walked by Germany's Kiel-based Neander Motors in several markets due to its two-conrods-per-piston, small-capacity diesel engines.
And it’s something that Austria’s Stevr Motors is ready to jump onboard with when it comes to taking on production of these new outboards. It was officially announced at the Monaco Yacht Show that Yanmar would begin global distribution of the Dtorque 111 outboard engine. This is after two years of promising pre-series trails conducted by both Yanmar and Neander across six European countries—including testing in Sweden at temperatures of 5 degrees Fahrenheit. In a port area that had been freed from ice, this engine ran perfectly in all speed and load ranges, starting and idling so reliably that the Swedish coast guard directly expressed interest in the technology.
"We invited a wide cross-section of our customers around Europe to performance-test the outboards in differing sea states and loading conditions gathering as many opinions as possible," explained Floris Lettinga, Yanmar Global Sales Manager. "Our research has confirmed that this product is ideally placed for the light duty commercial market…We are confident that the combination of long range, low running costs, durability and low emissions delivered by this unique diesel outboard will appeal to operators across a wide range of applications.”
Photos credited to Yanmar/Neander-Moto