The dependability of today's diesel engine, coupled with the many benefits of a single screw design, have made the decision to build the standard Nordhavn 46 as a single engine vessel an easy one. To begin with, the single engine is quieter and produces less vibration than twin engines, and the cost of annual maintenance is reduced. In a single-engine installation the propeller and shaft are protected by the keel from accidental grounding or floating debris, whereas twin engine installations expose the shafts, props and rudders to damage. And, of course, one engine consumes less fuel than two engines, increasing the vessel's cruising range. P.A.E., in recognizing the importance of the Nordhavn's engine, specifies the commercially rated Lugger L668D diesel with a heavyduty 3-l reduction gear. This power plant is designed to run and run, mile after mile, hour after hour.
The two arguments against single engine vessels are "get home'' emergencies and close docking maneuverability. In the first instance, the dependability of the Nordhavn's Lugger diesel engine is legendary. These engines have been known to run in excess of 20,000 hours without major service, and unless there is a fuel problem or cooling system failure, there is very little that can go wrong. P.A.E. has addressed these two areas by designing a foolproof fuel management system and eliminating the problems of a raw-water cooling system. In over ten years, nearly l00 single-engine Nordhavns have been cruising throughout the world, and there has never been a reported incident of a main engine failure causing serious concern.
To reduce the possibility of a water cooling problem, the salt water system with its through hull, strainer and raw- water pump has been replaced with a dependable keel cooling system. This completely enclosed, fresh water system allows no salt water to enter the boat or the engine. Instead, the water from the engine is circulated through a heat exchanger and cooled in the externally flush-mounted keel cooler. Gone forever are the problems of clogged strainers and failed raw-water pumps.
This intelligent approach to cooling is carried through to the engine's exhaust, where a dry system is used. Exiting the engine, the exhaust gases travel up a heavily insulated and mechanically suspended pipe that ends far above the deck at the top of the mast. Not only does this design minimize the smell and noise of exhaust fumes from entering the boat, it eliminates any possibility of water entering the engine through the traditionally installed exhaust hose. This attention to detail and smart engineering add to the overall dependability of the Nordhavn's main power plant. However, for those owners who want to eliminate all potential anxiety of cruising far from home port with one engine, the vessel is offered with an optional "wing'' engine that features its own electrical system, fuel supply, shaft and propeller. This low horsepower diesel engine, usually 27 hp, is capable of running the boat at 5 knots, assuring the captain the ability to get to port.
To answer the concern of maneuverability with one engine, an optional bow thruster gives the captain sure control in tight docking situations. It has been found, however, that with practice the Nordhavn 46 can be maneuvered using its prop wash against the large rudder as well as using the prop's natural tendency to walk the stern sideways at idle speed. If an owner has operated an inboard sailboat, he will have little problem docking a Nordhavn with or without a bow thruster.
The Nordhavn 46 engine room is a model of flawless planning and engineering. To begin with, the main engine is located low and on centerline, adding to the natural stability of the ship and allowing plenty of room to work around it. All surfaces are painted and insulated with heavy-duty foiled and leaded foam, and all insulated surfaces are shrouded with aluminum perforated paneling for a clean, shipshape look. A stainless steel fuel manifold system, designed by P.A.E., is clearly marked, fuel tank sight tubes are easy to see and recessed for safety, and filters are easily changed even when underway. Two fuel tanks totaling l,000 gallons are made from molded fiberglass and then glassed to the hull for added strength and years of trouble free service. They feature large inspection plates for interior access and cleaning, as well as baffles to reduce the noise of sloshing fuel.
The 46's engine room is designed to encourage routine maintenance and frequent inspection of machinery and systems. Neat, organized, well-lighted and with room to work, it provides a safe, welcoming environment.
