The SeaGlass Carousel at New York's Battery Conservancy challenged its designers to create an amusement park-style ride in an outdoor environment not especially conducive to the operation of such a ride. Welcoming the challenge as an opportunity for innovation, its engineers devised a unique ride structure whose design features showcase its ease of operation, reliability, safety and durability in its ocean-side setting.

SeaGlass Carousel is an automated, aquatic-themed ride within a spiraling nautilus-shell pavilion soon to be constructed at the tip of lower Manhattan. The carousel is designed to conjure the era at the turn of the 20th century when Battery Park was the first home of the New York Aquarium. The pavilion and original concept is the brainchild of WXY Architecture and Urban Design, while carousel production concept and design were done by George Tsypin Opera Factory. McLaren Engineering Group took on complete structural, mechanical, and electrical engineering for the ride system.

The project's all-electric, no-hydraulic design posed a particular challenge because of its location in an environment sensitive to temperature changes and atmospheric, salt-air moisture. Because the pavilion was designed without a fully enclosed wall, the carousel's intricate workings risked exposure to the elements. Its designers addressed this issue, however, by housing all of its machinery and electrical equipment in the facility's compact cellar, by using appropriate coatings and materials, and by clever detailing to collect and convey water.

Unlike traditional carousels, SeaGlass has all the structural supports and drive mechanisms beneath the ride's main turntable, creating a distinctive open-air viewing environment for the patrons as there is no revolving roof over the ride. The main turntable structure rides on a central ring bearing and a series of large casters rolling on tracks in the cellar.

Electrical cable management was an important element in the structure's design. A revolving slip ring, which resembles a tower covered with a stack of wire brushes, sits in the middle of the assembly to maintain electrical contact, distribute power, and effect signals for the ride. The slip ring is protected from above with a cover. The structure's complex control system is housed in the cellar, except for the ride operator control console, which has a complete view of the ride.

The project required precise electronics, a variety of rotating parts and rigorous specifications. The ride structure comprises one main turntable 46' in diameter, with three smaller turntables each 17' in diameter that are built into the main turntable and which spin on their own axes. The main turntable is powered by four electric motors with a friction drive—a rubber wheel that grabs onto and propels the turntable. The smaller turntables ride on ring bearings and are each driven by a separate electric motor.

When the ride is operating, the main turntable revolves continuously, while the smaller turntables twist back and forth within a total angle of 240 degrees. The system has built-in safety features such as a limit switch that is automatically triggered in the event of a malfunction—a turntable rotating beyond its prescribed pivot point, for example.

The motors, gearboxes, casters, control cabinets, electrical equipment, ring bearings, and other equipment all were specified with appropriate materials and coatings that can accommodate exposure to salt air, water, and temperature changes. The ride assembly contains water collection troughs around the perimeter of all gaps where there are interfaces between moving surfaces. These troughs convey water to pipes on the ride that deliver the water to perimeter stationary troughs and pipes outside of the ride, which then take the water to sump pits in the cellar. The troughs on the ride include clean-out hatches that catch any dirt and debris. The circular tracks bear on grout that has embedded plastic weep tubes to permit water to drain to the perimeter.

Electrical stub-outs and the slip ring base are elevated above the slab to avoid immersion if standing water were to collect temporarily on the floor during a storm. All on-board electrical enclosures were specified to satisfy National Electrical Manufacturers Association (NEMA) 4X requirements for enclosure protection.

A central feature of the ride is its unique patron seating: iridescent carriages sculpted like sea-glass fish that revolve on the four turntables, giving the appearance of fish floating in the ocean. The lifting masts for the moving fish carriages were made from hydraulic cylinder bodies to take advantage of the self-wiping seals, internal bearings and clean, finished appearance.

Twelve different sculpts will be used to create the fish carriages. The total patron capacity is 30 riders, one in each of 30 fish. Three clusters of four fish carriages will reside on the large turntable, between the three smaller ones. One of those carriages will be an ADA-compliant unit for patrons in wheelchairs. Each of the small turntables will have six fish carriages, which will include mechanisms to create vertical lift and side-to-side motion similar to a fish swimming through the water.

The carriages' lift and swivel action is produced by a compact, customized piece of machinery in the cellar designed to move the fish in a confined space in close proximity to rotating machines, to clear one another and the structure, and to enhance aesthetics by obviating the need for overhead lifting poles. The fish on the main turntable will be fixed. All told, the ride will have 25 separate axes of motion.

The ride will also include as many as 10 different programmed sequences to produce an individual effect of being part of a school of fish. This impression will be further augmented as the small turntables rotate like subgroups within the schooling fish, immersed in a multi-sensory environment with sophisticated lighting, projection and audio effects.

William B. Gorlin is vice president, Entertainment Division, for McLaren Engineering Group, based in West Nyack, NY.