Dean Barker's balancing act just got a little tougher with the minefield of San Francisco Bay's testing the Emirates Team New Zealand crew before the start of the next America's Cup World Series.

Skipper Barker was already dealing with the challenge of "switching off" from sailing the team's new AC72 catamaran, to hit the water racing their smaller AC45 in San Francisco - the scene for next year's America's Cup.  There was also the frustration of having to play catch-up to Cup defender Oracle and Swedish challenger Artemis, who've been training on the Bay for most of this month.

And now, there's the weather.  Since the Team NZ crew of six arrived in California late last week, the Bay has been dishing up 30 knot wind gusts and choppy seas, which have already claimed three of the 11 boats out practising.

Team NZ have come through the practice days unscathed, but not without a few hairy moments. Their training partner, Luna Rossa Swordfish, was not so fortunate - suffering a spectacular end-over-end capsize, destroying their AC45 wing.  The Italians will need to use another wing if they are to be on the startline when racing begins in earnest on Wednesday (NZ time).

The strong sea breezes and wind against tide also flipped Artemis and Team Korea, and could cause more carnage in this first event of the 2012-13 World Series.  But it will give Barker a better understanding of the Bay - he last raced there in 2005.

Barker admits leaving  the AC72 testing programme to sail an AC45 has been "challenging and frustrating".

"It's a real balancing act at the moment. In the end it's about winning the America's Cup, not winning AC45 regattas. But as a commercially funded team, our sponsors expect good results," he says.

"Our heads are very much in design and development, trying to manage this thing in Auckland. But then we have to turn up in San Fran, and switch over to the racing mentality pretty quickly.

"If we wanted to win the ACWS event in San Francisco, we should have been up here training too. But the big prize is still in the shed and we have to keep developing that."

Barker and his crew - Glenn Ashby, Ray Davies, James Dagg, Derek Seward and Jeremy Lomas - have had a handful of days to reacquaint with their boat. Shore crew have been in the US a little longer, making repairs to the AC45, damaged in a slow-motion capsize at the last ACWS regatta in Newport.

Team NZ finished the 2011-12 series second overall, behind Jimmy Spithill's Oracle crew, and Barker was in two minds about his performance.

"It was good, but we're not there yet. We know we can be a lot better. We were fairly surprised we started the series as well as we did; and disappointed we didn't string together good results at the end," he says.

Barker said he was also frustrated there had not been a lot of America's Cup-style match racing in the last series, with fleet racing the "preferred option" for television coverage.

"But San Francisco will see much more match racing, which will be great. To us, the 45 is about learning to match race catamarans in San Francisco, before we sail the 72 there. Fleet racing is great fun, with the course boundaries, and the closeness of the racing.  But you are developing skills for fleet racing, not for the America's Cup."

Under the new ACWS format, there is a clear separation between the match racing and fleet racing disciplines.  The fleet and match race champions will be decided on "Super Sunday" at each event.

Four time Olympic gold medallist  Ben Ainslie will sail his own AC45 team for the first time in San Francisco.

- © Fairfax NZ News