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Scott Strickland of Bonita Springs, FL asks:

I am interested in why Nordhavns have a wing engine. In looking at other manufacturers, they either do not offer one, or do not recommend one.

Jim Leishman responds:

Most Nordhavns have been equipped with a wing engine. This is a system which we developed and installed in our first NORDHAVN 46 about 13 years ago.

While many comercial vessels operate world wide with only one engine, most have competent engineers aboard and are well suited to deal with problems with their propulsion system. Aboard many yachts, the crews are less mechanically inclined and might have trouble with a significant repair at sea.

The wing engine operates independant of the main engine. It has a separate propeller shaft and propeller, electrical system and battery, a seperate fuel tank into which only fuel that has passed through a water separator and 2 micron filters can enter (it has no deck fill). Virtually any problem that might render the main engine, transmission, shaft or propeller inoperable, will have no effect on the wing engine.

The wing engine has the ability to bring a disabled vessel to a destination where machinery can be replaced or repaired - or help can be rendered. The wing does have limitations. It will have a hard time maintaining headway in any winds above 20 knots however I've never seen an auxillary propulsion system that will perform as well. In calm water the wing will push the vessel along at about 5 knots and the alternator can maintain the ship's batteries and allow continued used of all electronics.

For instance, if on our last leg (Cape Verde to Barbados - 2,100 miles) we ran over heavy debris or entangled our propeller in a discarded ship's hauser that damaged and rendered our running gear inoperative, the NORDHAVN could have continued on with the wing engine at speeds of around 4 knots instead of 6.5 knots. Without the wing engine - a thousand miles from land - a salvage tug would have to be called thus generating a salvage claim which could cost tens of thousands of dollars.

Or, say a fuel filter suddenly clogged and shut down the main down at a dangerous entrance to a harbor or anchorage, with the twist of a key the wing could be started and propulsion could be maintained without hesitation. The alternative task of clearing the filters, repriming the engine and starting - all short handed - could allow the boat to wreck and be destroyed and effectively put the lives of the crew at risk.

Alternate get home systems usually depend upon a belt or chain drive from a generator driven hydraulic system. The problem here is that it takes a huge generator to pull enough power from in order to effectively spin the main propeller. Also the tasks of installing the chain or engaging the belt all take time. In a hot engine room when you don't have time, this can be a big problem. Providing an alternate method of spinning the main propeller addresses only the issue of an engine problem. If the problem is the transmission, the shaft/coupling or a damaged or fowled propeller, this system will prove worthless. I personally think you have the greatest risk with the running gear - everything aft of the engine. This is probably where a failure will be.

The wing engine can also be used to maintain directional control and headway during fluid checks of the main engine when shutting down is necessary.

The wing engine adds less than 3% to the cost of an average equiped NORDHAVN 40 and most people consider it a good value, good insurance and good peace of mind.

 

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