Wild Oats XI receives another turboing
Bob Oatley’s Rolex Sydney Hobart race record holder and five time line honours winner, Wild Oats XI, today unveiled three significant additions to her armoury for this year’s race, which starts on Boxing Day.
All three changes have been designed to improve Wild Oats XI’s speed in light winds, and to provide an even better opportunity for her to break her race record time of 1 day 18 hours 40 mins and 10 seconds, which the 30m maxi set in 2005.
The improvements have come as a consequence of the big boat missing line honours in last year’s 628 nautical mile Hobart race by a mere three minutes after sailing for two days, 6 hours and 17 minutes.
Two of the changes have been made to the underwater configuration, and the third to Wild Oats XI’s sail inventory.
Keel Winglets: The most interesting change underwater is to the keel where winglets have been added to the aft end of the yacht’s 12-tonne lead bulb. These are not dissimilar to the winglets seen on the wingtips of modern commercial jet aircraft. At the same time, Wild Oats XI’s winglets could be said to have a lineage which extends back to the 1983 America’s Cup winner, Australia II, and her famous winged keel. Just as was the case with that yacht, and today’s jet aircraft, Wild Oats XI’s winglets have been designed to reduce drag by straightening out the flow of water coming off the trailing edge of the keel bulb: they minimise what are called tip vortices – speed-sapping turbulence in the form of small eddies. They have been designed by hydrodynamic and aerodynamic specialists, some of whom are involved with the latest America’s Cup yachts.
Retractable Bow Centreboard: After watching his yacht miss line honours in the 2011 Rolex Sydney Hobart race, Bob Oatley was convinced that one of the primary reasons for the yacht lacking speed in light winds was the drag caused by the two daggerboards which were fitted just prior to that race – and he was right. After extensive testing back in Sydney, and three months of hull surgery, Wild Oats XI was relaunched carrying the same daggerboards, but with another retractable centreboard fitted on the centreline three metres aft of the bow.
Mark Richards, the yacht’s skipper, explained this modification: "We weren’t able to trial the two new daggerboards prior to the last Hobart race, so it was only during the race that we realised we had a speed problem in light winds. When the yacht returned to Sydney we did a series of tests using extremely accurate GPS readings so we could analyse the yacht’s performance, and that led to us designing a symmetrical and retractable centreboard to be fitted near the bow. We now use that centreboard when sailing upwind in winds of up to seven knots, then we go through a transition phase as the wind increases in strength to a point where the centreboard is eventually fully retracted and one of the two existing daggerboards is completely down. When sailing downwind all three appendages are retracted to reduce drag."
Code Zero Headsail: If there was one thing missing in Wild Oats XI’s sail arsenal last year it was the very latest and largest possible Code Zero light-weather headsail – but that will not be the case this year. Bob Oatley has had made especially for this year’s race a headsail of gargantuan proportions – 535sqm … larger than two tennis courts. It is so large that the foot (bottom) of the sail will extend from the tip of the bowsprit to a point that is three-quarters of the way along the deck of the 30m long yacht. The sail, from North Sails in Sydney, is made using the very latest technology. The ultra-lightweight 3Di fabric comprises carbon, aramid and Dyneema yarns.
Mark Richards, who has skippered Wild Oats XI to all five of her Rolex Sydney Hobart race victories, gave his overview on the changes to the yacht: "Last year’s line honours result confirmed that every second counts, even in a race over 628 nautical miles, so this year we have gone in search of where we can gain seconds as well as, possibly, hours.
"The winglets on the keel will make us just that little bit faster in all weather, and the new retractable centreboard will give us more speed in light winds, as will the huge Code Zero headsail. That sail is like replacing a rifle with a canon.
"As was all too evident for us last year, we can’t control the weather, but we can go into the race knowing that we can do no more when it comes to having the fastest possible yacht, and that is the case this year. Thanks to Bob Oatley’s commitment, Wild Oats XI has never been better prepared for a Rolex Sydney Hobart race. Now it’s up to us – the crew – and the weather to decide the outcome."
The critical nature of these improvements is seen in the fact that had Wild Oats XI been just one second per mile faster in last year’s race she would have completed the course almost 11 minutes faster than she did – more than three times the difference between line honours and second place!