Science Headlines - America's Cup

Science Headlines - America's Cup

An information service for media in New Zealand

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RE-ISSUED 25 June 2007

All eyes are on Emirates Team New Zealand. Hi-tech New Zealand companies and leading university departments have contributed to the years of research, testing and training behind the campaign. Find out about the science of sail design; what makes good ‘grinding’; engineering for reliability and performance; and the world’s best wind tunnel.

1. Professor Richard Flay, Yacht Research Unit, hosted by the Department of Mechanical Engineering at The University of Auckland. The YRU draws together staff and students from across the university, particularly the departments of mechanical, civil and resource engineering, and physics.

Website: www.mech.auckland.ac.nz/staffpages/richardflay.htm and www.yru.auckland.ac.nz

"The Yacht Research Unit at The University of Auckland probably has the best wind tunnel facilities and testing procedures in the world. We make 1/15th scale models of yachts and sails – they’re about two metres high – and analyse how they behave in our special twisted flow wind tunnel, which mimics the natural wind flow out on the water. The wind tunnel can be used to test far-out ideas inexpensively, and those that look promising can get another look.

"A key part of the data we collect is from the ‘wind tunnel force balance’. The balance has six load cells connected to the boat. These measure the forces as we vary the wind conditions and the direction the yacht is heading. We record the driving, vertical, and side forces, and the pitch, heeling and yaw moments – and investigate which sails perform best in different wind conditions.

"During a wind tunnel test we feed the data from the ‘force balance’into our novel real-time ‘velocity prediction program’. This combines the sail data with a computer model of the boat hydrodynamics - the underwater wet parts, so the boat really sails and heels in the wind tunnel. Put these together, and we can accurately simulate how the boat might move through the water; see how fast she goes and how much she heels.

"We’re now working on a ‘dynamic velocity prediction program’. We’ll be able to simulate the effect of the waves on the sails, and the impact of tacking moves as well. It’ll be even more realistic than traditional velocity prediction programs.

"There are former staff and students from the Yacht Research Unit working for 8 out of the 12 Americas Cup syndicates."

2. Simon Pearson, PhD candidate at Auckland University of Technology's Institute of Sport and Recreation Research New Zealand: a multi-disciplinary research institute that conducts international level research in applied physical human performance.

Website: http://www.aut.ac.nz/schools/sport_and_recreation/research/isrrnz/

"The grinders’ role is to turn the cranks which control the movements of the sails. This dictates how quickly the boat can turn and how efficiently the wind is used. It’s a really important role.

"I’ve been getting a better understanding of the way the grinders move, and how that relates to their training. These guys have to be very fit. The loads they have to handle can be huge. They can be grinding full on for 10 seconds, resting for 30, then full on again. They need strength and stamina.

"We set up a simulator at the base, and got the Emirates Team New Zealand grinders in to use it. Because the wind and the water conditions change so much on the boat, we made it so we could tilt the platform, and increase the resistance at the grinding handles.

"It’s quite complex, but by using a combination of video analysis, force measurement and electromyography to analyse muscle activation, we’ve been able to really understand the biomechanics of grinding; the forces involved and how the muscles work together during the grinding action. As a result, we’ve been able to recommend changes to the gym-based training regime of the Emirates Team New Zealand’s grinders, and work with some of them to modify their technique."

3. Burns Fallow is a sail designer for the company North Sails. Burns also heads the Sail Department of Team Emirates New Zealand.

Website: http://www.northsails.co.nz/index.html

"Over 200 sails will be used in this campaign. We’re allowed to race with up to 60 sails, the rest were used in training, testing and the build-up. Some of these sails can be as big as 500 m2. The raw skin is made in Nevada and they’re finished at the base in Spain.

"The sails are designed using CAD, software that allows us to visualise the sail in three dimensions. We also use a program that simulates wind flow over the shapes we’re experimenting with. Once we’ve perfected the design, the software can instruct the pneumatic rams that make the unique mould the sail will be made on.

"Mainsails and upwind headsails are made using ‘three dimensional lamination’, or 3DL. Layers of high-performing materials are laid over a unique mould created out of a moveable floor, shaped by pneumatic rams. The floor is made from aluminium plates covered by a rubber membrane, and can be manipulated by the computer to form the shape we need. This means that the sail is built up in one piece, not from panels being glued or stitched together.

"A layer of Mylar is laid over the mould. Kevlar and carbon fibre yarns are placed over it by a computer-controlled plotter, then another layer of Mylar. This is placed in a vacuum and heat-sealed to set the adhesives and ensure strength. It can take 24-30 hours to finish a 3DL sail.

"The marine industry is too small to develop new kinds of fibres or materials itself, but each America’s Cup cycle acts as a spur to drive changes in technology, and the way in which we use the materials. We piggyback off the advances in other industries, and in turn they can benefit from our experiences. For example, before carbon fibre was used in sails, no other industry used it in a way that demanded it to be flexed and handled so much."

4. Michael Eaglen, Engineering Division Manager, High Modulus International. The company supplies composite technology and structural engineering services to the marine industry, and has been involved in the design of several of the current crop of America's Cup yachts, including the Emirates Team New Zealand yachts.

Website: www.highmodulus.co.nz

"Construction of America's Cup class yachts is a highly refined and competitive process. Maximum performance has to be achieved at a minimum weight, within tightly defined rules. The engineers involved are turning their focus towards very specific and highly specialised materials, and increasingly, the detailed structure of the materials.

"Engineering in composite, ‘fibre-reinforced plastic’, materials is very different from that in metals. But using a custom-designed combination of different high-tech fibres at a range of orientations, set in a matrix of thermoplastic resin, gives us limitless options.

"In the America's Cup, small gains in structural efficiency can bring large gains in racing performance. By designing new construction materials, engineers can put
strength exactly where it's needed, leading to highly efficient structures - lighter, stiffer and stronger. But boats are subjected to a wide range and combination of loading scenarios, making the design process extremely complex. Ultimately the efficiency, effectiveness and reliability of the structure are all limited by the engineers' understanding of the materials, process and loads.

"Understanding the effect of variables that were previously considered insignificant pushes the technology outside the sphere of even quite advanced design engineering."

Science Headlines is a service managed by the Royal Society of New Zealand and funded by the Ministry of Research, Science and Technology.

ENDS

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