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The arT of creaTing a really fasT superyachTtext by bransom bean
The Need for
SPEED
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The Need for Speed the need for sPeed
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yacht to have reached 70 knots). “So we zero base everything,
looking to optimize power, weight and shape.”
Like everything else about a superyacht, it seems that there’s
a special art to creating a really fast superyacht.
“Owners won’t go to all this trouble if it doesn’t look and feel
like a luxury yacht,” reminds Blount.
KinD of a Drag The enemy of speed is drag or resistance. Sadly, in this battle for
speed, drag has many allies and sometimes defeating one only
reinforces another.
Drag increases with speed until the accelerating hull reaches
a sort of terminal velocity, called hull speed. Or, if there’s enough
power for the geometry of the hull, she lifts majestically up from
the water onto a graceful plane, shedding hydrodynamic drag
and gaining even more speed.
“And that’s when weight distribution gets really important,”
says Blount.
Drag can be visualized as things protruding from an otherwise
To own The floaTing work of arT ThaT is a superyachT
means being one of the very few who possess something very
special, a sophisticated confirmation of success and good taste.
But to own one that is really fast, well that raises the game to a
whole new level. Designing and building a high-performance
superyacht is not for the faint of heart or shallow of pocket.
“A high-speed yacht project is not easy,” observes Bill Blount
of Donald L. Blount and Associates, which has done the naval
architecture for some of the world’s fastest superyachts, includ-
ing the 136-foot, 68-knot Fortuna, the former Spanish royal yacht.
The problem is that the science of naval architecture is unques-
tionably one of the most challenging. Like predicting the weather,
the variables involved are almost endless, and achieving the
ambiance of a superyacht only makes it harder.
“It’s essential to find a compromise in naval architecture,”
says Luca Bassani, Wally’s founder and CEO, whose yachts look
like they’re doing 100 knots at anchor. The WallyPower 118
Galeocerdo is the fastest Wally ever built, with a 60-knot cruising
speed and 64-knot top speed.
Going faster on water is a sorcerer’s blend of calculations and
compromises within an envelope of physics’ implacable laws.
“As a yacht gets faster, it becomes more unforgiving, so the
process needs to get more technical and less artisanal; it becomes
a finely engineered product,” says Antonio Caviglia of custom
builder Otam. “We become very meticulous.”
So, in chats with yacht designers it’s much more common to
hear, “The trade-off is….” rather than Computational Fluid Dynam-
ics, Froude number or the Admiralty coefficient.
siMpLe, in TheoryUnfortunately it’s not just a question of adding more power.
That’s what Australian Ken Warby did in 1978 when he set the
(still standing) world unlimited water speed record at 511.11
kph (317.596 mph) in his Spirit of Australia. But the Spirit of
Australia is no superyacht. She is a 27-foot home-built boat
whose weight almost matches the thrust of the military surplus
Westinghouse J34 jet that powered her. The only concession to
comfort? A seat for Warby.
“Remember, we want to build a fast luxury yacht, not a stripped-
down race boat,” says Bas Mulder of Mulder Design, designers of
the world’s fastest superyacht, The World Is Not Enough (the only
designed by dutch naval architect frank Mulder, The World is Not enough was built by Millennium super yachts, John staluppi’s and John rosatti’s company. she is propelled by two Paxman diesel engines and two Lycoming gas turbines, producing a staggering 20,600 horsepower.
Builder: Millennium super yachtsLoa: 140'
propulsion: triple water jetsMaximum horsepower: 20,600 hp
Fortuna was built at izar for King Juan carlos of spain, who is renowned for his penchant for speed. she is propelled by three rolls-royce gas turbines and two Man diesel engines.
Builder: izar Loa: 136' propulsion: triple water jets
this yacht has been kept a closely guarded secret and she has undergone an extended development program. this unique propulsion system has no less than six gas turbines and three water jets.
Builder: devonport (Pendennis Plus) Loa: 164' propulsion: triple water jets
Gentry eagle was built by the late tom Gentry, a speed fanatic. his passion to win the blue riband for the fastest atlantic passage drove him to build Gentry Eagle, in which he and a crew of five set a record time of 62 hours, seven minutes in 1989. she was relaunched as a yacht in 1992.
Builder: Vosper thornycroftLoa: 111' 11"
propulsion: single surface drive /twin water jets
Maximum horsepower: 11,560 hp
top 10
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1 The World Is Not Enough | 70 knots
2 Fortuna | 68 knots
Alamshar | 65 knots
4 Gentry Eagle | 64 knots
these pagesThe World is Not enough (above) set a record as the world’s fastest
yacht but her 70 knots pales in comparison with the current standing water speed record established by Spirit of australia (left), essentially a rocket strapped to a hull. pershing made a name for itself with fast
production yachts using various propulsion options; the pershing 82 (previous page) is equipped with rolla surface piercing propellers but
pershing also has used turbines, most notably on the pershing 115.
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tion in the last twenty-five years,” observes Øino. To prove the point
he points to two yachts with similar volumes separated by two
decades. Smeralda at 925 gross tons was delivered in 2012 and
displaces 560 tonnes—a ratio of 61 percent; Eco (now Enigma)
delivered in 1991 at 1,030 gross tons displaces 1,000 tonnes or
almost double Smeralda’s displacement, with a 97-percent ratio.
“A higher budget is essential to reduce weight without sacrific-
ing comfort because it allows you to use the most advanced mate-
rials,” says Bassani. “But the fantasy of the client is infinite and it
can increase more and more the weight of the boat.”
poWer, JusT giVe Me More poWer“On the other hand there really hasn’t been a similar quantum
leap on the propulsion side,” observes Øino. So to go faster, as in
the Spirit of Australia, you can always add more and bigger engines.
“But as it relates to motor yachts, the power output options are
relatively fixed,” says Blount. “So the owner and naval architect
need to have a clear understanding of the project’s performance
expectations. The owner during the design or construction phase
may desire a change from the original design. The naval architect
needs to communicate the impact of that change, as it may require
an increase in the original power output to continue to meet the
owner’s performance expectations.”
smooth hull. So stabilizer manufacturers offer retractable versions
and “zero-drag” fins. Low-drag rotary stabilizers take advantage
of the Magnus effect—the reason for dimples in golf balls.
The other option is to just eliminate external stabilizers alto-
gether, replacing them with gyroscopic stabilizers, massive
flywheels spinning at very high speeds that work like a child’s
top. Those made by Seakeeper are aboard yachts built by Azimut,
Feadship, Wally, Gulfcraft and Sunseeker, to name a few.
It’s obvious that the hull’s shape or geometry affects drag, which
at its simplest is why the bow of a boat is narrower. Finding the
optimal shape for the entire hull was a hit-or-miss affair until it
became a measurable science in the last century with tank testing,
scale models pulled through a tank of water.
But a quantum leap forward with the development of hull
geometry is the use of computational fluid dynamics (CFD), where
the model and tank are replaced with software and computers
using complex algorithms to analyze simulated fluid flow. “CFD
helps us shave off drag elements including appendage design
throughout the boat’s shape,” says Blount.
You can also reduce drag by reducing friction between the
hull and the water; a clean, slippery bottom is the goal. The first
order of business is discouraging organisms like barnacles and
weed, something that is hard to do given environmental concerns
but not impossible. Akzo Nobel, makers of industry standard
coating AwlGrip, says customers using its just introduced Inter-
sleek Pro are reporting drag reduction of almost 10 percent
completely without biocides.
Then there’s air. Once any vessel gets to 50-knot speeds, aero-
dynamics becomes important; remember the stall speed of the
Douglas DC3 is 58 knots; the Piper J-3 Cub stops flying at 33 knots.
“Classically, yacht exterior designers are interested in aesthet-
ics,” says Blount. “But yachts using gas turbines need wind tunnel
tests just to make sure enough air will get to the engines, and
the ducting of exhaust avoids having a low pressure area that
collects exhaust gases where the owner wants to stand and watch
the shoreline fly by.”
sheDDing Those eXcess pounDs“But enemy number one of going fast is weight; you must focus
on weight and weight distribution,” says Espen Øino, designer
of legendary yachts 509-foot Al Said and 414-foot Octopus as
well as some very fast ones like 115-foot Moon Goddess, capable
of 45 knots, and all-carbon fiber 125-foot Shooting Star with a
top speed of 48 knots.
Reducing weight also reduces the boat’s draft, which as a
bonus allows the boat to go more places where the water is
shallower, like The Bahamas. Less weight also means less lift is
needed to get the boat up onto that all-important plane, when
the physics changes again.
Obvious ways to reduce weight are lighter batteries and using
lighter materials in the hull and superstructure, traditionally alumi-
num but more commonly now carbon fiber, Kevlar or ARAMAT,
a combination of Kevlar and fiberglass with a weight reduction of
six to 12 percent over conventional fiberglass, aluminum and steel.
(Titanium has been mooted. During the Cold War the Soviets built
seven Alfa class submarines with titanium hulls, but titanium is
expensive, even by superyacht standards.)
The holy grail of greater strength and lighter weight is possible
using finite element analysis (FEA) software early in the devel-
opment of the structural design.
Luxurious materials are often heavy. There’s a lot of weight
in marble and hardwood, but natural stone and wood veneers
reinforced with aluminum honeycomb transform that beauti-
ful finish to feather-light. It can reduce the weight of marble by
up to 75 percent.
Some very curious things have been done in the unending
quest for lightness, like replacing ceramic toilet bowls in the crew
accommodations with lighter stainless steel.
“There has been some tremendous progress in weight reduc-
the WallyPower 118 Galeocerdo’s sleek design is the result of an extensive r&d program. she is driven by three Vericor tf50 gas turbines, each driving a rolls-royce Kamewa water jet.
Builder: Wally/intermarineLoa: 118'
propulsion: triple water jets Maximum horsepower: 16,800 hp
initially called Mercury, this yacht was designed by Peter du cane for the Greek shipping tycoon stavros niarchos. she has three gas turbines combined with surface drives as well as two conventional engines for low-speed maneuverability.
Builder: Vosper thornycraftLoa: 103'
propulsion: triple water jets / twin screwsMaximum horsepower: 13,620 hp
designed by rob humphreys, this high-speed yacht was constructed in carbon fiber with every component analyzed to save weight. she is powered by three Mtu 16V 4000 M90 engines, each rated at 3,650 horsepower and Kamewa jet units.
Builder: McMullen & WingLoa: 123' 3"
propulsion: triple water jets Maximum horsepower: 11,000 hp
a Mangusta 108, Nobody’s engines set her apart from others in the series: two Lycoming gas turbines combined with water jets.
Builder: overmarineLoa: 110'
propulsion: triple water jetsMaximum horsepower: 8,770 hp
top 10
5 Galeocerdo | 64 knots
6 Brave Challenger | 60 knots
7 Ermis2 | 57 knots
8 Nobody | 55 knots
(cont.)
these pagesa computational fluid dynamics study
by naval architects BMT nigel gee for an oceanco project simulates how water will
interact with the hull (left). espen Øino has several fast yachts to his credit, including
(above, clockwise from left) Moon Goddess, Smeralda and Shooting Star.
78 SHOWBOATS INTERNATIONAL78 SHOWBOATS INTERNATIONAL
The Need for Speed
LosT in TransLaTion“Traditional fixed pitch, fully submerged propellers reach a
natural tip speed/blade load limit, after which cavitation occurs
with resultant loss of performance and physical erosion of the
blades,” says California-based designer Doug Sharp.
Or in other words, once you’ve settled on the power plant, the
objective is to save as much of the power created by your choice
of diesel engines or gas turbines and to minimize the power lost
as it’s delivered to the water, usually via screws/propellers or
water jets. “The objective is to try to optimize for two ideal speeds,
cruising and top speed,” says Øino.
Propeller shafts and brackets create drag, and as propellers get
larger in diameter they give the yacht a greater draft.
“A traditional propeller is efficient up to twenty-five knots or
so,” observes Johan Huber of Voith, “and water jets really come
into their own at forty knots; our Linear Jet bridges that gap.”
Voith has become synonymous with marine propulsion. The
company’s entry into superyachts has been its ultra-quiet thrust-
ers now specified by top yacht designers like Øino. Reputed to be
the propulsion of John Staluppi’s latest James Bond yacht, Project
Skyfall, Voith’s latest innovation is the Linear Jet with a double
walled nozzle nestled again the hull for reduced noise and vibra-
tion and a shallower draft.
“Water jet technology improvement, depending the manufac-
turer and their respective series of water jets, has increased their
efficiency by ten percent over the last decade,” says Blount.
Another option, surface drive units reduce underwater drag by
50 percent in a setup that moves the propellers to the stern and
raises them halfway out of the water. A “free” aesthetic accessory
is the spectacular rooster tail of white water thrown up astern of
the yacht, letting everyone know you have them.
WhoLe LoTTa shaKin’ goin’ on“Naval vessels can’t hide in port when it gets rough,” says Blount.
“Owners of well-designed high-performance yachts shouldn’t need
to either.” High speeds at sea can mean miserable pounding when
the seas begin to build and that can literally destroy an interior
designer’s creation. “Accelerations are a killer for human comfort
and put heavy loads on a lighter structure so the light weight
necessary for performance means problems with comfort and
structure,” says Sharp. “So the balance of weight to comfort and
speed is the primary focus for top-end performance.”
Sharpening the bottom into a deep-V improves rough weather
performance. “Our designs quite comfortably take two- to three-
meter seas at forty knots, using twenty-one degrees of deadrise,”
says Otam’s Caviglia. “But we know our yachts are subject to more
stress at these speeds.”
To strengthen their hulls, Otam makes all bulkheads structural,
joining hull and deck. All tanks are integral parts of the hull. And
a final structural touch is that all furniture is custom built into the
yacht. “Like a tailor-made suit,” says Caviglia.
a sign of The TiMesSo what happened to sedate, slow and stately lifestyle that was
classic gin-and-tonic yachting?
“Our typical owner does like to sit in one place quietly and enjoy
all the delights of the sea, but they also happen to be people who
want to get there fast,” says Caviglia.
“Life in general has become faster,” says Øino. “In the past you
carefully drafted a letter, sent it off regular post or airmail if you
were in a hurry; once it got to the other end, the recipient might
have it in the in-tray for a day or so before posting back your
answer. Now, we fire off an email, and if we don’t get a response
the next day we worry that something’s wrong.”
Baglietto is a builder of yachts synonymous with speed. Its sales
manager, Giulio Bertani, observes, “Owners no longer have to
compromise comfort to achieve speed. ‘Yacht-addicted’ owners
who are also committed to doing business all over the world need
to fit their cruises in a limited timeframe. Yachts able to reach
distant places at a high speed are essential to them.” •
Daloli (ex-AA Absolute) was designed by frank Mulder and was built by heesen yachts in 1995 for the sultan of brunei.
Builder: heesen yachtsLoa: 120'
propulsion: triple water jetsMaximum horsepower: 9,520 hp
Launched in 1995, Sun ark is another performance yacht designed by frank Mulder and built by heesen.
Builder: heesen yachtsLoa: 120' 3"
propulsion: triple water jets Maximum horsepower: 9,520 hp
for more fast yachts, visit boat international online at: www.boatinternational.com/yachts/the-register/top-20-fastest-yachts/.
top 10
9 Daloli | 54 knots
10 Sun Ark | 54 knots
(cont.)
Voith Linear Jet