Ivor Wilkins talks to the men behind the whole of the AC45 fleet and two AC72s... Core Builders Composites directors Tim Smyth and Mark Turner

Simultaneously revered and reviled for their technical complexity and expense, the new AC72 America’s Cup class is as spectacular on the water as it is challenging to design and build. In all likelihood we will never see this class again. But the boats will certainly be remembered by all who see them in the flesh – and by those tasked with their creation.

For Core Builders Composites in Warkworth, New Zealand the complexity of the build highlighted the value of their investment in large multiple-axis CNC milling machines, which greatly increased the speed and accuracy of construction. ‘Without this capability we would have had to design and build the AC72 components and wings quite differently,’ says Tim Smyth, who founded Core with Mark Turner in 2001. ‘It would have been much more time consuming and not as accurate. Some of the complex shapes we have been able to produce would not even have been contemplated without this technology.’

Smyth refers to it as digital boat - building, the ability to translate a threedimensional model space supplied by the designer on a computer file effortlessly and accurately into a physical entity, whether it is a tool or a part. ‘It means, for example, that the aero team can be unfettered in the shapes they come up with.’

In their neverending quest to smooth airflow and reduce drag, the aerodynamicists constantly run model shapes through CFD programs, tweaking the surfaces for the best solution. ‘They are now able to do this virtually without constraint about whether the preferred shape will be too difficult to build,’ says Smyth.