What is in this article?:
- Powering the world's largest motion platform
- Meeting high expectations
The challenges of moving a 60-ton, full-size replica of a sailing ship for one of Hollywood's latest movies are explored.
Try to imagine the size and power of the hydraulic system required to move a 60-ton movie prop mounted to the world's largest motion platform. But the dazzling special effects needed in Master and Commander: The Far Side of the World called for some dramatic engineering, not only in sheer physical capabilities, but in the sophistication of motion control as well.
The 60-ton prop is a full-size replica of the H.M.S. Surprise, a 179-ft sailing ship boasting a towering 130-ft main mast. From the outside, and the right vantage point, it looks just like a seaworthy sailing vessel. But inside, it's obvious that this is nothing more than a sophisticated stage prop.
Imagine the size and power of the hydraulic system required to move a 60-ton movie prop mounted to the world's largest motion platform. But the dazzling special effects needed in Master and Commander: The Far Side of the World, called for some dramatic engineering not only in sheer physical capabilities, but in the sophistication of motion control as well.
The ship replica is mounted to a huge motion platform capable of moving in three axes: roll (pivot along the longitudinal axis), pitch (pivot along the transverse axis), and heave (vertical displacement). Hydraulics brings life to this monstrous mechanism, and, as is usually the case in applications such as this, all hydraulic and mechanical motion components are hidden from view. Two giant hydraulic power units that drive the hydraulic system had to be hidden as well, so they were positioned more than 100-ft from the motion base. This presented a challenge to system design because such a long distance would normally slow response to sudden flow demands. However, proper line sizing and strategic placement of accumulators kept system dynamics within required specifications.
Each of the three motion axes had to produce smooth and precise motion, without jerky movements. Controls had to be easy to operate and allow making changes quickly on-the-fly. Safety was also important because roughly 130 actors, stunt men, other professionals, and extras were on board the Surprise replica during rehearsals and filming.
Setting the stage
Academy Award nominated director Peter Wier teams with Oscar winner Russell Crowe in this motion picture spectacle set on the high seas. Crowe stars as Jack Aubrey, a captain whose ship is suddenly attacked by a much superior enemy warship. Aubrey becomes a man on a mission and sets sail with his crew in a high-stakes chase across two oceans to intercept and capture their foe. Master and Commander: Far Side of the World (click to view trailer) is not only an epic tale of leadership and dedication, but a powerful story of the relationship between Aubrey and his trusted friend, played by Paul Bettany.
Before it was transformed into the H.M.S. Surprise for the film, the tall ship had been christened the H.M.S. Rose, and served as a floating museum in Bridgeport, Conn. Film makers purchased the Rose and converted it into the fictional H.M.S. Surprise. This seaworthy set is used in shots taking place out on the open seas. Because its movements can be precisely choreographed and controlled, the Surprise replica is used for closeups and scenes that must be carefully choreographed.
Film makers contracted Commander Productions Ltd., Los Angeles, to provide the Surprise facade mounted to the articulated steel framework, or gimbel, fixed to the bottom of a large tank at the shore of the Fox Studios set in Rosarito, Mexico (which was also used for the sea adventure films Titanic and Deep Blue Sea). This allowed commanding the ship replica through choreographed motions while it appeared to be far out at sea.
No bit-part for hydraulics
The sheer mass of this load made it a natural for hydraulics. Bosch Rexroth, Hoffman Estates, Ill., supplied the hydraulic system. The heave axis required the greatest force and stroke. To accomplish this, Bosch Rexroth provided four cylinders, each with an 8-in. bore, 8-ft stroke, and 2-in. piston rods. Not only did these cylinders transmit the most power in the application, they were the most critical because they were used in every scenario, and their motion had to be synchronized to handle the load and provide realistic motion. Had these cylinders moved out of synch, they could have applied uneven forces to framework. The resulting stress could have distorted the framework or even torn it apart.
For the roll and pitch axes, a Bosch Rexroth 4-ft stroke and 10-in. bore cylinder was specified for each. Although these axes required much shorter strokes, they still required large-bore cylinders operating at 1500 psi to move and control the 60-ton load. The motion of these cylinders was not synchronized, but each needed to work in tandem with the five other cylinders.
GS-Hydro U.S. Inc., Houston, also supplied the massive hydraulic power units, valves, and other hydraulic components, including 12 runs of more than 250 ft of hydraulic lines. According to Scott Cady, president of GS-Hydro, "Our design manager, Scotty Bearb, modelled a non-welded piping system in 3D that spanned a total of 4500 ft. The entire piping system was prefabricated in Connecticut and installed in Mexico in three weeks, after receiving the order."