America's Cup secrets will be exposed when Tauranga sailing enthusiasts hear how technology propelled Oracle to its come from behind win at last September's America's Cup, from two rival engineers.

In a nationwide free public lecture, Emirates TNZ senior design engineer Andy Kensington and Oracle Team USA's Neil Wilkinson, will discuss what took place off the water and out of sight at the 2013 series.

America's Cup designers will give a presentation at Tauranga Yacht and Powerboat Club.

The lecture ‘Battle of the Boats – how technology won the America's Cup' sees the pair go head to head once more, debating the technology that allowed Oracle to come from behind and steal New Zealand's lead, winning last year's thrilling race.

Billed as the America's Cup story the public hasn't heard, the lecture is hosted by the Institution of Professional Engineers New Zealand celebrating the IPENZ Centenary Year and showcasing the revolutionary design and technology used in the race.

As part of the six stop lecture tour, Tauranga Yacht Club will host a lecture on Thursday evening. The public will hear how teams worked into the night behind closed doors, using cutting-edge technology and making last-minute changes to give the boats a winning edge.

Starting at 6.30pm, the 45 minute presentation is followed by a 15 minute question and answer session.

The two New Zealand engineers, Kensington originally from Tauranga and Wilkinson originally from Christchurch, will discuss how they, and other designers, pushed technology to the limits to develop these revolutionary boats, their strategy and the key design changes made once racing begun.

But even after the series the pair remain at odds; disagreeing on the individual innovation features that had the biggest impact on the race and about the impact of money. But both agree on one point – technology helped win the Cup.

Neil describes the intense, pressure cooker environment he and other designers, engineers, sailors and shore crew worked in, surviving on fewer than five hours sleep, while making last minutes changes to the boat, giving it a fraction of an edge on the water the next day.

He says once racing begun the competition was so tight that any difference was miniscule, but on the water it was magnified and had the ability to alter the race outcome.

Neil admits last year's challenge is the toughest race series he has ever worked on of the six America's Cup series he has been involved with.

'We had a number of tweaks, modifications and changes. When the Cup racing started we finally realised that Emirates Team New Zealand had a slight edge upwind so that's what we started concentrating on, trying to reconfigure the boat to improve its performance upwind,” says Neil.

'We were working on the boat until at least 10 or 11pm the night before races, just making small changes and fine-tuning the boats, having them ready to race at 6am the next day.

Andy agrees the pressure throughout the race had both sides dangerously close to breaking point, looking at every possible opportunity to gain an edge. And this is when minor design and technology changes became so important.

'It was pretty nerve wracking making any changes during racing, but at the end of the day it's a yacht race. Mental and physical strength count for a lot, but it's a sport with a huge variety of technology - it's the silent partner that intertwines it all,” says Andy.

Looking back he says it is clear the race game changer was in the middle of the series, but will not provide further until the series of lectures.

The free public lecture on Thursday at Tauranga Yacht Club, 90 Keith Allen Drive, starts at 6.30pm.