Corkscrew (Silverwood)  Corkscrew is an Arrow Development prototype Corkscrew roller coaster located at Silverwood Theme Park. Ten exact replicas of this same design were produced 1975–1979 at other scattered parks, followed by numerous other installations around the world featuring updated supports. After being sold as the prototype, this corkscrew originally operated at Knott's Berry Farm from 1975–89. Developed by Ron Toomer of Arrow Dynamics, a Utah-based design firm, the "Corkscrew" was the first modern steel inverting roller coaster open to the public, with identical models opening at three other parks days later. After the train is dispatched from the station, it enters a small dip and into a short U-turn followed by a 70-foot-tall (21 m) chain lift hill. When the train reaches the top of the hill, the train slopes down and into a 90-degree banked turn. The train then enters the first drop and goes into a small camelback where rides experience a sensation of airtime. The train makes a sloped banked right turn and into a set of two consecutive corkscrews. The train then travels through one final 90-degree banked turn and into the brake run which leads back to the station. When Corkscrew first opened at Knott's Berry Farm, it achieved two things of historical significance. Corkscrew was not only the first modern inverting coaster in the world, but it also was the first roller coaster to take riders upside down twice. Corkscrew was actually a prototype originally built on site at Arrow Dynamics in Mountain View in Santa Clara County, California (before Arrow Dynamics' relocation to Utah). Once Arrow Dynamics completed reviewing the design, members of the Knott's family personally opted to purchase the prototype. Ten exact replicas were produced 1975–1979. In 1989 Knott's Berry Farm sold the Corkscrew to Silverwood Theme Park in Idaho for $250,000 to make room for Boomerang.