Update
‘HOW DID THINGS EVER GET SO FAR?’ – Jack Griffin When Don Corleone opened the meeting of the Five Families with those words he was bemoaning the state of affairs among the mafia syndicates. The heads of today’s America’s Cup syndicates might use those same words to admire the state of AC yacht design. Remember that when teams started working on AC72 concepts
for the 2013 America’s Cup some leading designers declared that foiling was inefficient if not impractical and that skimming was the winning concept. Oracle’s Boat 1 was not initially designed to foil and when kitted out for foiling was hard to control. Artemis did not re-orient the design of Big Blue, their second AC72, until after their first boat, Big Red, had been smoked in an unofficial brush with Oracle’s B2. By 2017 Team New Zealand, the originators of foiling in the
America’s Cup, had developed the fastest foils, combining enough lift for light conditions with low drag for more wind and higher speeds. After winning in Bermuda the Kiwis raised the ante with their crazy, improbable AC75 concept that turned out to work well and, more surprisingly, gave us entertaining racing. So how did things ever get so far? Now that AC race boats fly
we need to look at both boats and aeroplanes to understand how we got here. This month we’ll look at boats, next month aeroplanes. In 1861(!) English engineer Thomas Moy towed a boat with hydro-
foils through the Surrey Canal and noted that it lifted ‘quite out of the water’. In 1906 Enrico Forlini was foiling across Lake Maggiore in his motorboat and the March 1906 Scientific Americancontained an article by William Meacham explaining the principles. Fast forward to the 1950s and Gordon Baker’s experiments for the US Navy with the foiling monohull sailboat Monitor, reportedly hitting 30kt. Videos even show her doing a foiling gybe. Monitor can be seen at the Mariners’ Museum in Newport News, Virginia. The next big wave of development came from the Moth Class.
14 SEAHORSE
In 1974 Frank Raison (no relation) built a foiling Moth – a wooden scow with surface-piercing V-formation foils made of heavy timber – a start. Then, in 1994, Andy Patterson developed the first narrow Moth – a tri-foiler with a foil on each corner that foiled but couldn’t get around a course well enough to race competitively. In 1998 Dr Ian Ward (regular contributor to these pages) mounted
T-foils on outboard wings but now with a mechanical sensor. It was stable until one foil hit disturbed flow and then launched Ward off the boat. Then in 1999 Ward simplified the concept with the first centreline foils – on the centreboard and the rudder. The boat foiled well and crashed equally well since weight shifts were the only control. We’ll come back to control systems next month. Then, at last, someone won races with a foiler. In 2000 Brett
Burville won two races at the Moth Worlds in Perth on Windrush, a Mark Pivac-designed tri-foiler with surface-piercing V-foils. These foils were the ancestors of the foils with dihedral developed on the AC45-based test boats in the build-up to the 2017 America’s Cup. This breakthrough showed that foiling was viable for racing. Windrush is now in the Fremantle Maritime Museum alongside Australia II. There was great debate in the Moth Class about whether or not
to allow foiling. To keep the Moth a monohull development class a compromise was reached and the ‘One Hull’ rule was reinterpreted to require that all foils exit the hull below the static waterline, elim- inating wing-mounted foils. After 2000 things really accelerated! In 2002 John and Garth Illett, with help from Burville and Pivac,
went back to Ward’s 1999 centreline concept and added a height- sensing wand. The Illetts sold their first production boat to Rohan Veal, the poster boy for foiling. Veal contributed mightily to devel- opment of the boat and to how to sail it. The wand linkage system became smoother and more respon-
sive. When the boat lifted off speed doubled and apparent wind went forward, so sail trim had to go from deep camber with twist to flat and untwisted. Veal also learned that 15-20° of windward
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