There is a strong aerial content to all four episodes, the main deck show is based upon a huge 23m diameter arched lattice structure of aluminium and steel. "This proved particularly interesting," continued Bergese. "This is a first for any cruise ship; Paul Staples did the design for me, Atkins the engineering, and Total Fabrications built it. I'd worked with Chris Cronin at TFL before, but this was a very different kettle of fish for us both."
"The challenges are three-fold, how to protect the integrity of the structure against the oceans corrosive elements, how to resist the dynamic pressures of rough seas and crashing waves in stormy weather, in combination with all the dynamic safety factors for the various performance apparatus."
"There is plenty of established data and engineering practise on how to combat maritime corrosion," explained Cronin. "We're using what are called 'sacrificial anodes', positively charged pieces that actively attract the oxidising agents, localising corrosion onto easily replaceable parts. The difficulty is learning how to interpret and apply such information to a structure not normally seen in such a hostile environment." The mix of two metals exacerbating this difficulty, steel and aluminium are uncomfortable bedfellows, even on dry land.
"Dealing with the additional dynamic loads of stormy weather presented an entirely new challenge for us. We needed to improve structural resistance to potential loads from virtually any direction, by approximately +20%. However, at the same time it was essential to ensure that the structure and how it attaches to the ships deck, is not so strong as to compromise the ships safety. In other words, there has to be a point at which it breaks away, rather than rips the main deck off."
Then of course there's the aerialists themselves: "I'm engaging several aerial skills," continued Bergese, "tissue performers, cloud swingers, there's even an element of bungee, plus a very daring acrobatic routine staged on a platform at the very top of the arch. Despite this and all the engineering challenges, everything I wanted has been achieved, and TFL has provided a very happy solution."
(Sarah Rushton-Read)
