Nordhavn 63 Hull Details

First Nordhavn 63 Performance Data

First Nordhavn 63, named Silver Spray -- Photo by Owner, Courtesy of PAE

First Nordhavn 63, named Silver Spray -- Photo by Owner, Courtesy of PAE

Pacific Asian Enterprises, Inc., yesterday released the first published performance data for the new Nordhavn 63.  The data are from the first hull, Silver Spray, which was just delivered to its owner at PAE’s Stuart, Florida commissioning facility.  As you can see in the accompanying photo above, taken by the yacht’s owner, the N63 truly looks like the “next-generation” N62, the aft-pilothouse trawler that was a customer and fan favorite all through its production run.  PAE has a lot riding on this yacht and it could become the right model to help bring the next generation of luxury distance-cruising boaters to the brand.  It’s large enough to accommodate truly sumptuous appointments, yet small enough to be easily handled by a couple without crew.

The First Nordhavn 63, Silver Spray -- Photo Courtesy of PAE

The First Nordhavn 63, Silver Spray -- Photo Courtesy of PAE

In the table below, you can see that the sweet spot for cruising will be a little more than 8 knots.  The fuel consumption basically doubles from 8.1 knots to 9.30 knots.  And of course, as with nearly every other hull like this, if you slow down you get better range.  Here you can see the NMPG at 7.55 knots is 1.42, which is very good performance for a yacht that displaces about 143,000 lbs.

The N63 hull incorporates an interesting design detail called a “maintenance strake.”  We wrote about it here.

You can download the complete performance data sheet here.

Here is a link to the Nordhavn 63 webpage for full specs and information.

 Nordhavn 63 Cruise Performance Data

RPM KNOTS GPH NMPG % Load
1216 7.55 5.30 1.42 41
1314 8.10 6.70 1.21 48
1597 9.30 12.70 0.73 75
1706 9.50 14.85 0.64 88
1803 9.80 17.05 0.57 100


*Performance based on average of 2 reciprocal-course runs.  Data from Nordhavn 6301, equipped with a single Lugger 1276, and a 5-bladed 42″ x 29.5″ P Hung Shen prop.

Copyright © 2011 by OceanLines LLC.  All rights reserved.

Posted by Tom in Boats, Cruising Under Power

Boat Design: A “Maintenance Strake” on the Nordhavn 63

N6301 Hull With Maintenance Strake Highlighted -- Original Photo Courtesy of PAE

N6301 Hull With Maintenance Strake Highlighted -- Original Photo Courtesy of PAE

We ran a story yesterday with some new photos of the Nordhavn 63 debut hull in construction at the factory in China.  As many of our readers know, part of the Nordhavn “mystique” is a result of the reputation of its full-displacement, bluewater hull designs.  These are the products of PAE’s chief designer Jeff Leishman, younger brother of one of the company’s co-founders and design contributors, Jim Leishman.  Over the years, the basic hull designs have been continually refined and have benefited from tank testing and analysis.  If you look closely at one of the photos from yesterday’s article, which I have marked up here with a black oval and arrow, you will see a somewhat unusual appendage on the bottom of the hull where the keel fairs into the flatter line of the hull bottom.  It looks in this angle to be a kind of bulbous addition to the hull.  Being a reporter and not afraid of my own naiveté, I decided to ask PAE’s Dan Streech about it.

“We call those ‘maintenance strakes’,” says Streech.  “They provide the room inside of the boat to walk around the engine.”  It sounds like an interesting way to add depth to the engine room.  Obviously, it would slightly increase the displacement of the hull, but I wondered how they came up with this idea and what the effect is, hydrodynamically speaking that is.  The answer Streech provided sheds a little light on the nearly unlimited sources of imagination and inspiration of the Leishmans.  According to Streech, “Jeff and Jim conceived and invented those while sitting on a turbo-prop plane and noticing all of the bumps, bulges and nacelles which didn’t seem to prevent the plane from flying.”  Streech adds, “We tank-tested them and actually found a reduction in drag (for reasons which were never fully explained).”

Cessna Caravan with Baggage Fairing -- Photo: Wikipedia Common License

Cessna Caravan with Baggage Fairing -- Photo: Wikipedia Common License

In the photo above, you see a Cessna Caravan, a turbo-prop-powered passenger and utility plane which uses a large faired extension on its fuselage (the “hull” of an airplane) to achieve a similar capacity increase.  Given that the aircraft is not designed for speeds higher than a couple of hundred miles per hour (relatively slow in commercial aviation terms) the drag penalty is negligible.  It would probably be somewhat different if the Caravan were intended to fly supersonically, but that’s a different kettle of fish.

Copyright © 2009 OceanLines LLC

Posted by Tom in Boats, Technology