With an Interceptor, a RHIB and a Cat Chasing America’s Cup BoatsCup BoatsBy John Hayneswo extreme AC72 foiling with peaks slightly over 2.0 times the catamarans with wing sails speed of the wind. The extreme foiling went head-to-head at over catamaran design means that AC72 rac-40 knots in San Francisco ing takes place on the edge of control. T TBay, California. The teams There is potential for crews to fall were competing in the 2013 Americas overboard or to require immediate at-Cup Challenge which took place from tention in case of injury. Each team is September 7-21, 2013. allowed a Chase Boat and to provide a Anyone watching the ? rst few days margin of safety these high speed craft of Americas Cup sailing will know that need to not only match the race boat it looked like Emirates Team New Zea- speeds, but to be able to exceed them.land had a seemingly untouchable lead With the wing mast / sail set up if a – then out of the blue Oracle Team USA crew breaks something, they can’t just completed one of the greatest come- turn and go home, because the wing backs in sport to win the 34th America’s stays loaded up. Cup. For anyone who has watched the The support boat has to be able to rising speeds of sailing records plus the tow an AC72 home faster than the wind development of hydrofoil technology, speed, which can mean towing at 25 this event was also bound to be a game knots. The boat also needs the puling changer for ‘power versus sail.’ Another power to be able to right an AC72 after race was on in San Francisco Bay as a capsize – fast.Chase Boats and Umpire Boats utilized The crews try to avoid the dangers of gasoline and diesel engine horsepower a capsize but it is a possibility that sup-versus the AC72 boats utilizing wind port teams must plan for.energy, aerodynamics and hydrodynam- Tragically in May 2013, British ics. Olympic sailing champion Andrew The AC72 is a state-of-the-art design ‘Bart’ Simpson died after the Swedish wind powered craft. Overall length is America’s Cup craft he was sailing cap-86 ft. (26 m), waterline length is 72 ft. sized and broke apart in San Francisco (22 m) and it has an extraordinary beam Bay. Simpson, a 36-year-old two-time of 46 ft. (14 m). The boat only weighs Olympic medallist, suffered multiple 13,000 pounds (5900 kg), it has a maxi- blows to his head and body in the acci-mum draught of 14 feet (4.4 m) and is dent involving the 72-ft. Artemis Racing handled by a crew of eleven. catamaran. The San Francisco medical The AC72 rises out of the water on examiner’s report said, ‘In the moments foils and designers always expected it before it capsized, the yacht was turn-to sail faster than the wind. Predictions ing downwind in a so called bear-away were upwind at 1.2 times the speed manoeuvre while travelling at about 30 of the true wind and downwind at 1.6 knots, with wind of about 20 knots. The times the speed of the true wind. But the front of the vessel then dipped beneath AC72 has proved to be faster, averaging the surface, the port hull broke and in-about 1.8 times the speed of the wind, verted on top of the wing.’www.marinelink.com 41MR #3 (32-41).indd 41 MR #3 (32-41).indd 41 3/5/2014 11:36:37 AM3/5/2014 11:36:37 AM