| Royal Huisman 117 |  |
No one talks about the hull design in powerboats," said Tony
Castro. He was standing in the salon of Arcadia, the 117-foot (35.7-meter) motor yacht he
designed that was realized in a two-year build by Royal Huisman Shipyard.
The focus of many owners, Castro offered, is on layout, fabrics and use of
space—creature comforts, but none of those elements directly contributes to
improving the yacht’s performance. Arcadia’s owner proved the exception.
| Click on the Spec and Design tab at top to see complete list of resources. |
He wanted a long-range boat with classic lines that was up to
cruising in the cold extremes of high latitudes and could handle bluewater
passages. Interestingly, the team he assembled has a decided sailing pedigree.
"I’ve designed sailboats for 27 years, motor yachts for 15," Castro said. Royal
Huisman has built more than a few groundbreaking sailboats, but Arcadia is only the
fourth motor yacht it has produced since 1981. Interior designer Dick Young also
has a sailboat-laden portfolio. According to Castro, the owner brought with him an appreciation of the
journey, the allure of the passage, garnered over 16 years of cruising on his
65-foot Jongert motor yacht. With an engineering background, the client had an
understanding and respect for what it would take to deliver a boat equally adept
at making the journey as it was at being at its destination. It was that vision that
allowed—actually required—Castro to design a motor yacht that "produced an
extensive preliminary design and 250-page specification."
 Photograph by Roy Roberts. (Click image to enlarge)
"We kept it light by choosing Alustar, a strong material with
properties 20 percent better than the alloy usually used. Huisman also made
lightening holes in all the frames," Castro said. The favorable
strength-to-weight ratio allowed the yard to go above the minimum Lloyd’s
100 A1 scantlings and still keep the weight within limits. Castro relied on the
Maritime Research Institute Netherlands (MARIN) and its pre-design CFD
(computational fluid dynamics) analyzing tools to optimize the hull shape. Not wanting to widen the relatively narrow 27-foot beam to
increase stability, Castro added weight low in the boat. Carrying 10 tons of
lead, cast into four separate tanks in the skeg, Arcadia insists on
staying upright. Two tanks on either side of the centerline forward of the
engine room hold 1,974 gallons of freshwater; trim weight that can also be
adjusted by adding water as fuel is depleted. To optimize the weight below the
waterline, the mast was built of carbon fiber instead of aluminum, resulting in
a 50 percent lighter mast.
 The Nautica RIB. Photograph by Hans Westerink. (Click image to enlarge)
Castro gave Arcadia balanced spade rudders, the type used on
many sailboats. The rudders extend deeper in the water and provide 50 percent
more surface area. The choice made perfect sense to him, but he still tested his
theories first. Combining his ideas and MARIN’s CFD data, he recalls that "it
worked rather well." The lower 35 percent of each rudder is sacrificial and
designed to break away in the event of grounding, leaving the majority of
material and a functional rudder stock behind. Forward of the rudders, two 61-inch, five-blade
Wärtsilä props turn on Akerboom oil-lubricated shafts. Each is fully enclosed
along its length, eliminating water friction with the fast-turning shaft,
increasing efficiency and reducing waterborne noise.
|
; function voidFunc() { } voidFunc();)
; function voidFunc() { } voidFunc();)
Email This
Printer Friendly Version
Reprints & Permissions
Most Popular Searches
; function voidFunc() { } voidFunc();){kind=link}