Yachting: Battery failure brings $10m of complex componentry to a standstill

Luna Rossa sail past as Team New Zealand slow to a standstill approaching the third mark. Photo / Aber Kingman

Despite all the complex and expensive componentry that goes into the hi-tech AC72 catamarans, all it took was a malfunctioning battery pack to end Team New Zealand's day on the water.

On track to record their second point of the Louis Vuitton finals yesterday with a 400m lead over Luna Rossa, Emirates Team New Zealand puttered to a standstill as they approached the third mark - the same area of the racecourse where they struck trouble on day one.

Initially there were fears from Kiwi fans the breakdown could be related to Sunday's dramatic nosedive, in which Team NZ lost two men overboard as their bows plunged into the waves, until it was revealed the problem was an electronic failure which was resolved with a simple change of batteries.

Team NZ grinder Derek Saward said the battery pack controlled the hydraulics of the boat - without them to control the wing and the daggerboards, the $10 million boat was crippled.

"This particular problem we've never had before; we've got systems in place that minimise the risk of these things happening, because obviously it's a race-ender. We go through those every night after yachting and every morning before yachting and those were done again today, and for some reason we had a mal-function and the guys were working to see what the problem was."

Team NZ's retirement from the race handed Luna Rossa their first victory over the Kiwis in 13 years of competition as they levelled the Louis Vuitton Cup finals at 1-all. The second race of the day was called off as the wind strengthened later in the afternoon, compounding the Kiwi crew's frustrating day on the water.

After the shore crew put in long hours in the shed overnight to repair the damaged fairing that was torn away when the torrent of water flooded on board, Saward said the team were gutted they could not reward their efforts with a victory.

Races three and four have been pushed back into today's reserve day.

Saward insists his crew will have no concerns about pushing the boat today and the mishaps have not dented the team's confidence.

In fact, confidence in their on-the-edge racing machine seems only to have been reinforced after Sunday's incident. While it was scary for viewers at home, Team NZ designer Nick Holroyd said the readings that came off the load sensors once they got the boat back on shore indicated they were nowhere close to reaching their limits.

"For sure it was a significant event, but there were no massively significant loads. We saw some unusual loads, but not what I would put in the magnitude of scary," said Holroyd.

The sleek 72-foot catamaran underwent a full structural inspection after the incident, with no signs of damage or deterioration detected, despite being subjected to extreme g-force as the boat decelerated from 40.7 knots to 13 in the space of a boat-length.

"When you see the bows dig in like that for sure you know you are in for a busy night, but the load casings were designed to be relatively extreme," said Holroyd.

The shore crew applied a temporary fix to the cosmetic damage incurred, replacing the torn carbon fibre with old fairing. Holroyd expects to have new fairing installed by Thursday.