Team New Zealand America’s Cup defense to be designed and visualised on SGI computers

by Scott Houston on 19 Oct 2001 SGI computers will help shape New Zealand’s Americas Cup defense, as SGI becomes
an exclusive supplier of design computers to Team New Zealand.
As competing crews launch practice boats this month on the waters of the Hauraki Gulf,
SGI will work with Team New Zealand to help deploy the yachting world’s most
sophisticated virtual modeling capabilities in the bid to win the America’s Cup for a third
time.

The next year sees the beginning of what some consider the real race – the planning and
building of the fastest sailboat in the world. The design brief extends far beyond the hull,
to nearly every part of the boat.

Team New Zealand’s designers will use the SGI computers to model the loading of
structures, and solid design of items like rudders, hinges, and mechanical devices.
Computer modeling allows structures to be virtually stressed, showing how much loading
they can take and where they’ll deform. Team New Zealand uses this data to decide
whether to make fixtures lighter or heavier.

The failure of one component can spell disaster. Sails can tear, masts snap, or worse.

Team New Zealand syndicate head Tom Schnackenberg says 3D visualisation is the key
to achieving group ‘buy-in’ on proposed design changes.

“With 3D visualisation, a group made up of different disciplines can see and understand
exactly what is being proposed and why”, he says.

“Fluid flow is a good example of this. Without visualisation, we can’t see the movement
of air and water, just the effects of disturbance. By colouring areas of high and low
pressure, we have a visual analysis of what is a very complicated phenomenon”.

The team visualises pressure maps over a boat’s hull, keel, wings and sails, then makes
changes to the boat design based on what is occurring.

“We can make a change to the hull shape, and from the flow visualisation, we can
understand how that might affect the boat’s speed”, he says.

Building and testing computerised ‘virtual’ models is faster and cheaper than the
traditional method of physically building models and testing them in tow tanks.

It costs between twenty and fifty thousand dollars to build and test a boat design using a
tow tank. From a computer-designed model, a physical model is constructed in New
Zealand to scale from wood, fibreglass and foam. The model is shipped to the U.K and
towed through a towing tank to measure drag, at a cost of ten thousand dollars a day. In
contrast, a design can be tested overnight on a computer.

“Our goal is to replace towing tanks with computers, but sailboat design is one of the
more difficult tasks for computational fluid dynamics”, says Tom Schnackenberg.

“It’s very much easier to model airplanes or submarines because they operate in either
air or water, not both. A yacht is an interface vehicle, requiring a solution, which takes
into account both water and air flow. We must also factor in the free surface of the water,
which can go up or down, as well as mast and sail combinations. I’ve been working with
these problems for twenty-five years. It’s still a combination of science and magic, but
the science is getting better all the time”.

It’s not just the shape of the hull and appendages, but also the shape of the sails that is
a prime task for computer modeling, and here the tools are more fully developed. Team
New Zealand's working with local Ph.D. student Stephen Collie to test different sail
shapes. Collie has worked with the Team over the last two campaigns, and is close to
producing ‘a real working tool’, according to Schnackenberg.

“Computational Fluid Dynamics (CFD) for foils is also highly developed, because you’re
operating in a 2-D world there. You can learn a lot from the 2-D world. Half way down the
fin, the flow is 2-D. The hull is 3-D – you have fluid going aft, outward and downward at
the same time”, he says.

SGI Managing Director Bill Trestrail says there’s great synergy between Team New
Zealand and SGI.

“SGI is helping Team New Zealand achieve insight into a very tough computing problem,
by deploying a combination of computational science and visualisation”, he says.

“This approach has proved enormously powerful for Team New Zealand - The last two
defenses saw Team New Zealand win 5-0 in a boat designed using SGI technology. The
2003 cup defense will be the third time Team New Zealand has used SGI to design its
hull. We’re very excited that our technology is again being used to design the fastest
race yacht in the world”.

In San Diego in 1995 Team New Zealand beat the world 5-0 using a hull and keel
designed using SGI technology. SGI renewed the supply agreement for the 2000 defense
in Auckland, and Team New Zealand again won 5-0.

There are three main components to SGI’s supply agreement with Team New Zealand.
An SGI computational system has been installed in the U.K; a New Zealand server
stores output from the U.K unit, manages internet connections and powers the entire
Team New Zealand computer network; and for the designers, eleven SGI high
performance design workstations.

The U.K unit is used to help replace towing tank testing of different hull designs, while
the workstations will be used to design individual keels, sails and other components.

A towing tank produces concrete numbers, but computer testing gives insights very early
on, by showing pressure distribution around a particular shape. SGI technology allows
Team New Zealand to pre-test a great many designs and variations, far more than could
be tested in a tow tank. Only the best make it through to be verified in the ‘real world’.

Team New Zealand writes a small quantity of its own CFD software, but enjoys a close
relationship with AEA Technology in the custom development of CFX features – for
example turbulence modeling - required for analysis of racing yachts. Ph.D. student
Stephen Collie is also working to customise CFX to the specific requirements of sail
shape analysis.

Team New Zealand will use 2001-2002 to design its entry. By the end of 2002, the
challenger series will heat up, ready for a February 2003 final.

About SGI
SGI provides a broad range of high-performance computing and advanced graphics
solutions that enable customers to understand and conquer their toughest computing
problems. Headquartered in Mountain View, Calif., with offices worldwide, the company
is located on the Web at www.sgi.com.

SGI is an exclusive supplier of design computers to Team New Zealand in its bid to win
the 2003 America’s Cup Yacht Race.