America's Cup- World's first AC72 to be launched by catapult
by Warren Douglas on 20 Jul 2012
What do you do when you need to launch a new boat in style but can’t risk breaking a bottle on the bow?
Launch Rehearsal - Emirates Team NZ AC72 - Viaduct Harbour, Auckland, New Zealand © Richard Gladwell http://www.richardgladwell.com
Pouring the bubbles over the boat is not quite the same, especially when the public is turning up and they’ll be expecting to see some action.
The trouble is that the bottle – a jeroboam weighing 6kg - if swung with sufficient force to break could also damage the boat.
The Emirates Team New Zealand AC72, which will be named at 5.30pm on Saturday night at a ceremony at Viaduct Harbour, Auckland, is built from carbon fibre over a honeycomb core. The boat is strong and light and engineered to withstand massive forces when sailing. But the impact of a large bottle would be like a blow from a sledgehammer and carbon fibre structures are not designed for that.
Emirates Team New Zealand design engineer Jamie France was presented with a brief to build a device for the 'champagne moment'. It must allow the bottle to break without taking out the boat, it must capture the broken glass and the public must be able to see the action from on shore.
It also had to be rugged enough not to be pulled off the boat by the combined strength of the 1000 people on the launch crew pulling on a rope to position the bottle for the big moment.
So what’s the solution? Build a trebuchet, of course. That’s what the French call a catapult. This is a catapult in reverse. Rather than flinging the bottle into the air it will arc down.
Version 3 of the trebuchet is now ready for service on Saturday night. It works perfectly. The bubbles will splash beautifully, the broken glass won’t pollute Viaduct Harbour and at 3m high, it will be seen from afar.
The AC72 was splashed for the first time on Friday - and towed briefly without her wingsail.
The wind forecast for the weekend is not promising with fresh easterlies predicted at the the of the launch on Saturday and the alternative date of Sunday July 22, 2012