Yachting: Oracle mast takes breath away

This is a wing. No, it's a sail. This is a wing. Okay, but since when was a sail bigger than a jet airliner's wing?

When the America's Cup goes loopy, that's when. BMW Oracle's massive 58 metre wing mast is a gobsmacking piece of kit. It is about 14 metres longer than the wing of the biggest passenger aircraft in the world - Airbus's A380. It is just short of the total wingspan, including fuselage, of a jumbo jet.

It is very, very big. It weighs 3500 kilograms and covers 2050 square metres. It is built of carbon fibre and kevlar, and covered with a skin of light, shrinkable aeronautical film.

Some reports claim the giant wing mast is so efficient that it easily turns 10 knots of wind into 32 knots through the water. Other reports say two to 2.5 times the windspeed is more realistic.

However, no one knows - possibly not even BMW Oracle - whether it will be used when Oracle's BOR-90 takes on Alinghi's giant catamaran, probably in Valencia in February. They art testing the rig to see what loads it can bear and how it performs.

Such things are tricky and take time. Even the conventional 'soft sails' on such a huge craft can come crashing down - as happened to Oracle's US$10 million carbon fibre mast earlier this month.

This is new territory and no one really knows what will happen. The theory is that the advantage of the wing over a soft sail is that it is easier to control and does not distort - making it easier for the trimmers on board to maintain a sail shape which gets the most out of the breeze.

Crash helmets, lifejackets and even body armour have been commonplace even during soft sails practices. A fall from a planing 100-ft trimaran going at 30 knots and from a height of about 40 feet can be damaging; not to mention giant masts falling over - uncharted territory indeed.

The huge rig also requires a motor on board to trim it and present it to the wind at the best possible angles and as fast as possible. But that's okay - America's Cup holders Alinghi created the precedent (at which many sailors sniffed contemptuously) when they unveiled their giant catamaran with hydraulics instead of human grinders to manipulate their sails.

It's tempting to say the America's Cup has never seen anything like this but it has - only smaller. Back in 1988, in the Michael Fay 'Big Boat Challenge,' the US team defied tradition when they unveiled an 18-metre catamaran equipped with a wing to compete against New Zealand's 27-metre monohull. But the 1988 wing height was slightly over 30 metres with an area of 165 square metres. Just a baby, then.

The BMW Oracle wing sail also has a distinct New Zealand element. It was built in Washington, with the Oracle building team headed by Kiwis Tim Smyth and Mark Turner. Another Kiwi with America's Cup experience is Brian Jones, of High Modulus, which was involved with KZ 1, 3, 5 and 7 and which helped several syndicates at the last America's Cup in Valencia.

Jones, who emphasises he has only seen pictures of the wing sail, says: "I'd say it will be extremely efficient, especially if they can control the twist of the rig. If they can control the twist and the camber of the thing it will be a lot more efficient than a fabric sail in terms of depth, shape and flexibility. Efficiency-wise, it will get a lot more out of the wind - whether it is light airs or in breeze."

However, it is not yet known how strong winds will affect the wing mast and its performance and it is maybe more aimed at combating Alinghi's catamaran, which is reputedly geared for lighter airs.

Many sailors are also curious to see how Oracle might handle launching and docking - the giant wing sail has to be manoeuvred into position by crane and it is a long process. The first time took nine hours as the wing was wheeled out of its shoreside assembly tent and lifted by two cranes onto the 30-metre trimaran.