Add Category
Updated
They call it sailing, but you could be forgiven for thinking the yachts in the modern America's Cup are actually flying.
The innovation-mad race has produced some of the most technologically-advanced boats. And rule changes in recent years have only sped this process up.
So how do these yachts work, and why do they look like they're flying over the water?
It's all about 'foils'
For the most part, the crafts in the America's Cup are just like traditional catamarans.
They have one enormous sail in the middle and two hulls either side that sit in the water. Wind provides the power and a team of six are put to work sailing it.
Then along came "foils".
Foils are essentially long, slender L-shaped carbon fibre hooks that are pushed down into the water when the yacht is already travelling at high speeds.
This lifts the hulls out of the water, giving it that flying appearance.
It's all about aerodynamics, veteran sailing journalist Patrick Bollen told News Breakfast.
"It works in the same was as an aeroplane. Foils create lift and in doing so create speed," he said.
The hull being out of the water drastically reduces drag and immediately increases the speed of the yacht.
Think of it like a turbo-boost, allowing the yachts to hit speeds of more than 80 kilometres per hour.
And this is allowed?
It is now.
The America's Cup has been running since 1851 but it wasn't until 2013 that foils were allowed.
"Foils have been talked about for years but the rules had not permitted it," Mr Bollen said.
"The whole boat is run by hydraulics, there's no manual winches now."
And it's not just being out of the water that matters; the angle of the yacht once airborne is also important.
Ideally, Mr Bollen said, you want the bow slightly angled down towards the water.
This means the breeze flows over the bow and creates an "apparent breeze" that is actually faster than the natural breeze, and therefore creates extra speed.
"Again it comes back to aerodynamics," Mr Bollen said.
Arms v legs
Until very recently, each hull of the yacht had four stations that control the hydraulics — including for the foils — and they were powered by the crew "grinding" with their arms.
This grinding is what keeps pressure pumping into the rudder, foils, sail etc.
"If the pressure drops too low, then you won't have the ability to function," Mr Bollen said.
Then last year the New Zealand team introduced a novel idea: rather than grinding with their arms, they built what were effectively bike stations where the crew would grind by cycling.
"By cycling or peddling, it's working on the basis that there is more power in the legs, which means you can pump more pressure," Mr Bollen said.
This arguably gives the New Zealand team more power, and also frees up their hands for other tasks mid-race.
Is this even sailing anymore?
Maybe not for some purists, but the America's Cup has always been a playground for innovators.
And it's all about those 1 per cent differences.
"Years ago change came in leaps and bounds, now it comes in millimetres," Mr Bollen said.
"The America's Cup is the forefront of sailing innovation."
Topics: sailing, sport, human-interest, united-states
First posted