January 19, 1998 Design News
Raise the Titanic!
Titanic's scale models weren't
just for show. Despite their enormous size, engineers
had to move them up and down as much as 34 feet
Charles J. Murray, Senior Regional
ROSARITO BEACH, MEXICO--The steel for the Titanic
set began arriving on trucks late in 1995. One by one,
an endless parade of flatbeds pulled into this oceanside
town, dumping loads of wide-flange beams, steel plates,
angle iron, and countless bolts for the throngs of construction
workers that followed. In all, there was enough steel
to fill the downtown of a medium-sized city. Assembled,
it would yield three massive structures, the biggest
of which was about the size of a 77-story building tipped
on its side. Ultimately, that set alone would weigh
more than two million pounds.
That, however, was not the most remarkable aspect of
Titanic. The most amazing part was that when
the last bolt had been locked down and the final board
was nailed in place, the film's director looked at the
massive scale model and said: Now move it.
Move it: Most engineers have never
imagined using those words in reference to two million
pounds. But that was what Titanic director James
Cameron wanted, and it was what the movie's special
effects coordinator, Tom Fisher of T.R.I.X. Unlimited,
planned to do. After considering several options, including
the use of barges to hold up the loads, Fisher called
engineers at Mayo Hydraulics, Bakersfield, CA and Parker
Hannifin's Motion and Control Group in Irvine, CA. "When
I first called and told them I wanted to move more than
a million pounds, they thought I'd gone crazy,"
Fisher recalls. "But they studied it, called me
back, and said: 'You can do it if you can pay the price.'"
Indeed, Paramount Pictures and Fox Filmed Entertainment,
co-makers of the film, will pay the price for a long
time to come. Already, Titanic is regarded as
the most costly film ever made, having come in at about
$200 million. But from the outset, Cameron was determined
to spare no expense when it came to technical realism.
That was why he built three massive sets in huge, man-made,
concrete-lined "lakes" for the movie's shooting.
It was also why he rented a submersible to dive down
to the real Titanic wreck and photograph it. And it
was why he demanded that the set designs--from the style
of the carpeting to the patterns on the wood moldings--faithfully
re-create the original.
Given those demands, giant scale models were
the only viable option. Unlike most sea-based films,
which make heavy use of models measuring a mere 10 or
15 feet long, Titanic would come as close as
possible to the real article. Engineers on the project
ultimately built a scale model measuring 775 feet long--about
90% of the size of the original. "In terms of sheer
size, no single movie set has ever compared to this,"
Fisher states. "And no one has ever moved a piece
this big for a movie."
Record-setting lift. The 775 ft-long structure,
however, was not the only scale model at the Rosarito
site. It was joined by two others: a 200 ft-long interior
set; and a 100 ft-long, hinged poop deck set, which
had to be tilted from 6 degrees to 90 degrees.
Because Cameron intended to re-enact the sinking of
the legendary ocean liner, all sets needed to be capable
of movement. The concrete-lined tanks, or "lakes,"
in which the structures were built, were up to 40 feet
deep, and the models needed to travel from the water's
surface to near-bottom.
To begin, crews built the steel structures at the tank
bottoms, before seawater was added. The first of the
models, the indoor set, measured 200 feet long by 120
feet wide. Built within the confines of an enclosed
building, it housed such indoor sets as the Titanic
grand ballroom, dining room, and the grand entranceway.
"From the outside, it looked like an unfinished
house," notes John Rothas of Mayo Hydraulics, a
member of the technical team.
Ultimately, the indoor set would be used for the movie's
sinking sequences, which meant that the structure would
have to be tilted, then lowered into the water. Some
scenes would be filmed by dumping large quantities of
water onto the set; for example, special effects experts
used trailers filled with water to simulate the scene
where water bursts onto the grand entranceway. By tilting
the trailers backward and equipping their doors with
explosive charges, they created a sudden rush of water
through the entranceway's skylight and down its grand
But for most of the key sinking sequences, the special
effects team needed to slowly immerse the sets in seawater.
"To achieve the shots we needed, we had to sink
the set," explains Fisher. "You can't make
an 8 million-gallon dump tank."
Moving the set at a prescribed speed and tilt angle,
however, took extraordinary power and control. "We
talked about putting the set on barges, then sinking
it," Fisher says. "But we wouldn't have had
enough. In terms of cost and practicality, the only
solution was hydraulics. To raise and lower it 15 times
a night, there was no other way."
Hydraulics the key. To move the 1.4 million-lb
indoor set, engineers employed a combination of power
media, including: a diesel generator set; electric motors;
and a mechanical pulley system; as well as hydraulic
pumps, reservoirs, valves, and cylinders. The diesel
generator, a 2,500-hp unit made by Caterpillar, was
necessary because of the lack of electrical power available
from the local grid. Thousand gallon-capacity reservoirs
for the huge hydraulic system were built on site by
engineers from Mayo Hydraulics.
To prevent damage to the steel structure, engineers
John Rothas and Mark Force from Mayo Hydraulics and
Greg Paddock from Parker Hannifin Corporation selected
eight attachment points (instead of four, as they might
otherwise have done), and divided the power media into
two equal systems. Each system consisted of four 200-hp
electric motors made by Lincoln Electric, Cleveland,
OH, which powered eight Parker Hannifin PAVC100 axial
piston pumps. The eight 100-cc piston pumps, operating
at 3,200 psi, transported hydraulic oil through four
Parker D41FH valves, which fed the hydraulic cylinders.
Each of the 12-inch diameter Parker Series 3H cylinders
had a 17-foot stroke, but a pulley configuration attached
to them provided a 2:1 mechanical advantage. As a result,
when the cylinders moved 17 feet, the pulley system
moved the model 34 feet.
Using four cylinders and eight pumps on each side of
the structure, engineers provided about 1.2 million
lbs of lifting force. Because the set weighed about
1.4 million lbs, they supplemented the system with foam
flotation, which was placed under the platform. The
foam flotation provided enough additional lifting capacity
to move the set as desired. It also added a measure
of safety, engineers say. "It wasn't safe to try
to lift that much weight with a single system--hydraulic
or otherwise," Rothas says. "The flotation
system was a good back-up."
Power and control. Lifting, however, was only
half the battle for the movie's technical staff. The
other half was control. Although they were moving the
1.4-million-pound load at a rate of six inches per second,
they wanted to synchronize the movement of all eight
cylinders to within ±1.0 inches of the commanded position
To accomplish that, they employed an eight-axis motion
controller and a master/slave control scheme. The "master,"
a 1/20th scale model of the platform, was controlled
by a two-axis joystick and a pair of hydraulic cylinders.
By moving the miniature, then sending its command signals
through an eight-axis digital motion controller, engineers
were able to create an identical motion profile for
the real model.
To synchronize the two, the motion controller compared
the eight command signals with electronic feedback signals
from the eight, 17-ft stroke cylinders. The motion controller
then processed the signals and sent an output drive
signal to each of the cylinders' servo valves. The cylinders
on the full-sized model then traveled to the desired
position at a pre-determined speed dictated by the master.
"The master-slave technique allowed us to create
an initial profile for the motion we wanted to achieve,"
notes Greg Paddock, a Parker Hannifin applications engineer
and veteran of several large movie projects. "Once
we had a feel for the platform movement, we directly
programmed the controller."
Programming for the system was done by engineers from
Distributed Motion, Inc. (DMI), a Parker Compumotor
distributor in Irvine, CA. DMI engineer Greg Stewart,
who did most of the programming, ultimately selected
an eight-axis motion controller made by Delta Tau Data
Systems, Inc., Northridge, CA. Use of the Delta Tau
technology enabled engineers to control all eight axes
with a single controller.
The big one. When they finished moving the 1.4
million-pound interior model, engineers dismantled the
power systems and prepared for the big job--moving the
90% scale model of the Titanic. A 6.6-acre outdoor "lake,"
located about 500 yards away from the indoor set, served
as the site for a two-million- pound scale model of
the ship. Built atop a 30-foot cliff overlooking the
Pacific Ocean, the outdoor model provided the look and
feel of an ocean liner at sea. "When you stood
on the deck and looked out, you saw the ocean,"
Fisher recalls. "You felt you were in the middle
of the Atlantic."
In truth, however, the outdoor set wasn't a ship at
all. Rather, it was a bolted steel web of wide flange
beams, columns, and trusses, like those in the skeleton
of any office building. Steel plates were bolted to
the sides of the steel skeleton to give it the appearance
of a ship. But below the water line, the steel facade