Does Cummins Make Diesel-Powered Marine Engines? Here's What You Need To Know

Cummins has been around for more than a century, providing diesel, natural gas, and alternative fuel engines for a variety of applications. Many are probably familiar with the company's work under the hood of commercial semi-trucks as well as the Ram 2500 and 3500 Heavy-Duty diesel pickups. In fact, 1990s Ram trucks came equipped with the Cummins 6BT, considered the best diesel engine ever made. According to Cummins, drivers choose its turbo-diesel almost 70% of the time on Ram trucks, which offer a monstrous 1,000 pound-feet of torque on newer models. 

What you may not know is that Cummins has also been manufacturing diesel marine engines since 1919. Due to the stress of operating in an aquatic environment, marine engines must be especially rugged in their design. For example, a marine engine must be capable of comfortably running at higher revolutions per minute than an automobile engine. While driving a car, you may hover around 2,000 rpm when you reach cruising speed. In a boat, the engine is required to rev much higher and remain there for sustained periods.

Cummins' first marine diesel engine was installed in a shrimp boat, and the company has gone on to become one of the top manufacturers in the field, with solutions for anything from recreational vessels to commercial and military applications. Just look at the Navy's charming barrier tugboats: the Boomin' Beavers, powered by Cummins' 6BTA5.9 diesel.

Cummins makes a 6.7-liter 6-cylinder that's the most robust high-speed marine engine ever made. For the purposes of powering a recreational craft, the QSB6.7 can put out between 230 and 550 horsepower with torque ranging from 720 through 1,250 pound-feet. A pair of these engines installed on a Huckins 38 Sportsman Hybrid was able to push the vessel to nearly 40 mph. According to Windward-islands.net, 40 knots, or 46 mph, is at the very top end of a typical yacht, unless specifically designed for racing.

Even more powerful is the QSK95, Cummins' largest engine. While the QSK95 pales in comparison to the world's biggest engines, it does offer an impressive 3,200 to 4,200 horsepower with a torque rating of 15,462 to 17,802 lb-ft. 

This massive marine engine is a turbocharged 16-cylinder with 95 liters of displacement. Two QSK95s were installed in the 45-meter passenger ferry Kilimanjaro VII, which operates in East Africa. With the brawny QSK95, not only can the vessel accommodate more people than the older Kilimanjaro VI, the Cummins engine still lets it reach 32 knots, or 36.8 mph.