Obviously, the motor-powered passagemaker depends entirely on its engine for propulsion, and a great amount of attention must be paid to selecting, installing and maintaining the power plant. The marine diesel engine has proven to be one of the world's most dependable machines ever made, and today's diesels are better and more reliable than ever. In fact, the undeniable reliability and resilience of these engines is key to Nordhavn’s promise to safely cross any ocean with absolute confidence.
All of the smaller Nordhavns are designed with a single engine in mind, although twin engine installations are available on most of the larger models. For the smaller yachts, the advantages of a single engine include greater economy and reduced noise and vibration. And, of course, maintenance is half of what a twin-engine installation requires. Most Nordhavns are ordered with a single main engine plus a smaller wing engine for "get home" power (Nordhavn’s mega-yachts, the N86 and N120, are designed with twin engines primarily because the diameter of the propeller required for a single-engine application would result in excessive underwater draft).
Because of the inherent efficiency of a full-displacement hull, the amount of horsepower required to drive the boat at hull speed is far less than what typical "trawler-like" semi-displacement boats require. When specifying horsepower, P.A.E. also uses the far more conservative "continuous horsepower rating" figure provided by the engine manufacturer, which is often half of what other boat builders will claim for the same engine. Be sure to compare horsepower ratings carefully, and remember that full-displacement hulls require far less power than other types of hull designs.
All Nordhavn designs call for extremely reliable and durable engines built to run for virtually weeks- or months-on-end and to be serviceable worldwide. Large, slow-turning props are best, so P.A.E. specifies gear ratios of at least 3-to-l or more. All engines are de-rated to ensure trouble-free, continuous use. In order to further reduce noise, wear and vibration, engines that develop their rated horsepower at low RPM are specified.
Owners sometimes have specific engine preferences, and because P.A.E. provides custom capabilities, it is able to accommodate the requests. Caterpillar, Cummins, MTU, John Deere, Lugger, Mann and Yanmar diesels have all been successfully installed on Nordhavns.