Nordhavn 56 motorsailer sailing trials

Nordhavn has recently launched the first of its 56-foot motorsailers. Now the vessel has undergone its first sailing trials off Dana Point, Calif. This boat is an interesting marriage of sail and power concepts. Designing a boat that can do both things well is a cool challenge for any designer and builder. Below are some notes by Nordhavn’s Don Kohlmann on the handling of the 56 under sail.

The Nordhavn 56 Motor/Sailing Performance

By Don Kohlmann, Sales Manager, Nordhavn Yachts Northwest, Seattle

Although the Motorsailer concept is not new, it now has more versatility and
value than ever. The apportioning of a Motorsailer¹s sail-to-power, or
power-to-sail, bias has always been a trade-off but, the advances in
machinery, deck hardware, and sail technology have made it more attractive
and enhanced the all-around performance by making sail handling easier, and
sail and engine power more effective and easier to integrate.  To be
successful requires a great design. The Nordhavn 56 is the product of a
designer, Jeff Leishman, and a company, Pacific Asian Enterprises/Nordhavn,
with critical experience designing and building both cruising powerboats and
cruising sailboats.
There are many reasons for the attraction to a Motorsailer that could
perhaps be summarized by a combination of the following points:
* For folks who don¹t feel comfortable going offshore without a sail
* For fuel conservation ­ extending the cruising range, even in light air,
with sailplan flexibility to create supplemental power and substitute power
* For stability and roll resistance
* For water collection ­ the mainsail can be a very effective watershed
* For Aesthetics ­ quiet propulsion when conditions permit
* For the interior volume afforded a boat that is not biased primarily
toward sailing
* For a view underway whether from the pilothouse, or from the forward
steering cockpit
Nothing gives a vessel windward and all-around ability like an engine and
propeller. Early tests under power have had the N56 easily achieving speeds
of 10 knots. The combination of a well balanced hull and sailplan, plus the
165hp Lugger diesel engine driving a Hundested variable pitch/feathering
propeller ­ as significant as its cost is – provides the optimum interface
between sail propulsion and power propulsion through a very broad range of
conditions, and ties together every point referred to above.  The N56  drive
train completes the Motorsailer concept by providing the ability to adjust
the power output, and attendant fuel consumption, to complement the power
developed in the sailplan.
Performance Under Sail –
Ever since the inception of the Nordhavn 56 Motorsailer, the question of
performance under sail has been the most pivotal. Now we can say
unequivocally, that the boat fulfills its purpose extraordinarily well ­ the
interior living and operating areas are spacious and comfortable, and the
performance under power and under sail is superb. The results of our early
light/moderate air sailing trials prove that the sail plan, in addition to
being a supplemental source of propulsion, is also a substitute source as
well. In fact, the results are as impressive for the 56¹s windward ability
as they are for its speed through the water.
Our early trials with working sails ­ full mainsail and 100% high-clewed
headsail – were conducted in light to moderate conditions of 8 to 13 knots
true wind speed (TWS), averaging 12-13 apparent wind speed (AWS), and then,
on a subsequent day, with an asymmetrical 1.5oz. all-purpose cruising
spinnaker in true wind speeds averaging 11 knots.  The water conditions were
light Pacific swell and light chop as the accompanying photos will show. The
headsail of suitable cloth weight for widely ranging conditions is intended
to produce minimal sensitivity to lead position, better visibility under the
foot of the sail, easier and more even furling or roller reefing, and to
allow more room on the headsail lead track for furled lead positions, but
does certainly compromise lighter air performance.  The tank condition was
full fuel and full water.  The boat is in live-aboard condition with respect
to stores and personal gear.
These conditions and the sail combination are one of the truest tests of
basic performance under sail for any boat.  Going upwind at apparent wind
angles of 50 degrees, produced apparent wind speeds of up to 15 knots and
boat speed through the water of 5.6 knots, with no indication of excessive
leeway.  Tacking angles were a very respectable 130 degrees on the compass –
especially given the boat¹s relative shoal draft of 6 feet – and would
clearly be closer in the wind range of the headsail, or with a larger
As we sailed wider apparent wind angles (AWA), 70 degrees yielded a speed of
6 knots, and in these conditions, further off the wind to 120 degrees
resulted in reduced boat speed of 4.25 knots as expected in these
The next day¹s results with the cruising spinnaker in conditions that
averaged about 9 knots true wind speed, produced speeds of a solid 6 knots
at an apparent wind angle of 75 degrees with 11 knots of apparent wind.

Aside from straight line speed through the water, the 56 responded very
nicely to the helm when manually steered and was very easy on the autopilot
when engaged.  The helm felt quite neutral, and most pleasing of all, it
showed no tendency toward lee helm which saps the windward ability of many
cruising sailboats, especially those in the heavier displacement-to-length
and sail area-to-displacement ratio class.
There are often conditions in the ocean when the wind velocity would provide
sufficient propulsion, but the wave conditions will not allow the boat to
accelerate sufficiently to build apparent wind.  The result is that the boat
will tend to slat in away that will prevent the sailplan from being
effective at propelling the boat and also prevent it from producing an
effective component of stability.  The addition of engine power creates
forward motion, which, at the right apparent wind angle, will create enough
apparent wind to render the sailplan effective at supplementing the engine
power and at providing stability.  As it does, to boat will settle down, the
flow around the sails will remain attached as the sail shape is maintained,
and the engine power can be reduced to the threshold of the amount of
apparent wind necessary to keep the process going. Under some conditions,
this could occur with very light true wind, but very flat sea conditions.
Sail setting and sail trim were quite easy with the Lewmar self-tailing
hydraulic winch package. With the push of a button for the main halyard
winch hoisting the mainsail is quick and smooth.  The same hydraulic winch
can be used with the Leisure Furl boom furling line that rolls in and out
very smoothly and the mainsail feeds smoothly into the luff groove.  The
beauty of the boom furling system is that the mainsail remains fully
battened and retains is still plenty of draft in the sail to give it the
kind of power required to achieve the lighter air performance that we
experienced.  In addition, all of the mechanical components of the furling
system are near deck level.
With the hydraulic furling system for the headsail, setting it is even
easier.  As with the mainsail, the sail rolls in and out very smoothly, and
is trimmed using the hydraulic sheet winches mounted just outside the port
and starboard pilothouse doors.
The hydraulic spinnaker sheet/secondary headsail winches are located in the
aft cockpit just outside the aft pilothouse door and provide the same ease
of trim as the headsail winches.
Please note that hull #1 and #2 are currently at out Dana Point location,
and #1 will run North to arrive here in Seattle, by the end of April

By Ocean Navigator