Doyle Sails goes with the high-tech flow

By ADAM GIFFORD

Westhaven sailmaker Doyle Sails has taken a technological leap forward by developing a program which calculates the way air will flow around sails.

Managing director Richard Bouzaid said Sailflow took more than two years and $500,000 to develop, including $200,000 from Technology New Zealand.

"It's going to change the way we design sails," Mr Bouzaid said.

"Existing computer design software didn't allow us to measure the flow of air around sails and foils and determine their separation. This information is crucial in designing sails, not just for extra performance but also in helping to save weight."

Without computer modelling, sail designers usually have to test full-sized model sails on boats.

"That's one of the reasons America's Cup syndicates usually have two boats, so they can test things like sails and foils."

Mr Bouzaid is talking to cup syndicates about using the software in the 2003 challenge, as well as considering other applications for Sailflow.

"It could be adapted to anything which involves flowing," he said.

Doyle Sails is New Zealand's second largest sail loft, with annual sales of about $4 million, more than half from exports.

Mr Bouzaid said the firm had more than doubled since Team New Zealand first won the America's Cup, with much of the new business coming from supplying the large cruising yachts attracted here by the event.

The idea for Sailflow came during a conversation between Mr Bouzaid and scientist Cheryl Fillekes at the last Whitbread stopover.

Dr Fillekes, who earned a PhD from the University of Chicago in 1990 for her computer modelling of geophysical fluid mechanics, put together the funding proposal and led the design team, which also included graphical interface specialist Stuart Woolford and students from University of Auckland's School of Engineering under Dr Margot Gerritsen.

"The laws of physics that apply to fluid mechanics in the earth's interior are the same equations you need to solve problems in the ocean and air," Dr Fillekes said.

To do the task within a limited budget, the team built a Linux supercomputer by clustering eight PCs, each with two Celeron processors running at just under 500MHz.

The entire cluster cost $15,000. In contrast, the Linux clusters Weta Digital is using to render graphics for the Lord of the Rings films, which use SGI hardware, are costing about $15,000 a processor.

The application is written in C++, Fortran, an open source HTML (hypertext markup language) form generator called Zope to create the internet front end, and it sits on an open-source Postgresql database.

A demonstration version is up at www.sailflow.co.nz.

Dr Fillekes said the database was needed to store input parameters and diagnostic outputs, so the theoretical performance of different sets of sails could be compared.

It also meant the program could be used by multiple design teams without their being able to see competitors' data.

Dr Fillekes, who is now working for Virtual Spectator on digital image processing of digital videos, said it was just one part of a complex art.

"Richard [Bouzaid] is one of the foremost sail designers in the world, with decades of experience. I trust his intuition more than I trust my program, but it's a program which can jog his intuition."