Where the concept of the Volvo open 70 came from

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The Volvo Open 70 has set the standard for monohull racing yachts since it replaced the previous Volvo Ocean 60 design for the 2005-06 Volvo Ocean Race.

 

The Volvo Ocean Race 2011-12 features five of the latest iterations of this modern design classic and it will be a surprise if the 24-hour monohull distance record is not obliterated by at least one of them during the eleventh edition of the race.

 

The Volvo Ocean 60 design rule, known originally as the Whitbread 60 rule, was introduced in 1993 in an effort to reduce campaign costs whilst maintaining the high performance nature of the yachts.

 

This move was the beginning of the end for the popular but hugely more expensive maxi yachts. A fleet of 10 Whitbread 60s took part in the 1993-94 race, dwarfing the four-boat maxi fleet in what was their final round the world race appearance.

 

To some degree, the new rule was an attempt to level the playing field, by placing tight constraints on the boats’ physical dimensions and equipment, while leaving room for individual designer creativity within a “box” of maximum length, width and depth.

 

To reduce build costs, the new boats were built from Kevlar and foam. The use of carbon was limited to the spinnaker pole, sail battens and rudder stock. Large water ballast tanks were allowed to help the sailors balance the boats and deliver maximum performance from the huge rigs and sail plans.

 

Nine years and three race cycles later it was decided that the evolution and refinement of the Volvo Ocean 60 design had been taken as far as possible and with the arrival of new technology and construction techniques, a bigger and better design rule was commissioned to be used from the 2005-2006 race onward.

 

Known as the Volvo Open 70, this time the “box” of parameters defined maximum overall length and depth, minimum and maximum width, and imposed a weight range restriction of between 12.5 and 14.5 tons.

 

The allowance of carbon fibre as a construction material meant that although two metres longer than its predecessor, remarkably, a Volvo Open 70 weighed around 1,000 kilograms less.

 

A four-metre increase to the height of the mast allowed the Volvo Open 70s to carry up to 60 percent more downwind sail area than a Volvo Ocean 60. The Volvo Open 70 mainsail is also around 28 percent larger in area.

 

A carbon mast and boom and the replacement of heavy metal rigging with lighter, high-tech rope to support the mast, resulted in significant weight savings in the rig.

 

Already more powerful than the Volvo Ocean 60s, Volvo Open 70s were given another major performance boost from the use of a canting mechanism on their keels, rather than the water ballast used on the previous generation boats.

 

Driven by a pair of powerful hydraulic rams, the entire keel and its large lead-filled bulb can be swung out to 40 degrees on either side of the boat to counteract the force of the wind on the sails, dramatically increasing the boats’ performance and enabling them to reach speeds as high as 40 knots in the right weather conditions.

 

The use of a canting keel necessitated the addition of a pair of long retractable dagger boards to help prevent the boat slipping sideways when the keel was fully canted.

 

Two rudders rather than one, gives the crews more control at high speed, allowing them to push the boats much harder, particularly in windy offshore conditions.

 

In total, the estimated performance improvement of a Volvo Open 70 over the Volvo Ocean 60 is around 18 per cent. Put another way, the Volvo Open 70s boats are estimated to be approximately three weeks faster around the world.

 

The distance record for a Volvo Ocean 60 was set by Illbruck during the 2001-02 race, when they travelled 484 nautical miles in a 24-hour period.

 

Volvo Open 70 Ericsson 4 broke the World Sailing Speed Record for the greatest distance covered by a monohull in single a 24-hour period. On Leg 1 from Alicante to Cape Town, Ericsson 4 sailed 596.6 nautical miles (1104.9 km) in day, at an average speed of 24.85 knots (46.02 kilometres per hour).

 

Confidence is high that the 600 nautical mile barrier will be broken during the 2011-12 race.

 

Volvo Ocean Race measurer Shaun Ritzen believes that after three races worth of development, there is now little design evolution left around the Volvo Open 70 rule.

 

“The latest generation boats are very similar to each other and the only areas the designers don’t seem to agree on is the deck layout and the position and angle of the daggerboards. Consequently the teams are having to resort to looking closely at actual the wording of the rule to try to gain some advantage from the way it can be interpreted.”

 

Volvo Ocean 60

 

Length - 60 feet, (18.2 metres)

Width - 17 feet, (5.25 metres)

Depth - 12 feet, (3.75 metres)

Weight - 29,700 lbs, (13,500 kilograms)

Water Ballast - 11,000 lbs, (5000 kilograms)

Sail Area - Upwind: 2,200 square feet, (205 square metres)

- Downwind: 4490 square feet, (417 square metres)

- Total:4690 square feet, (622 square metres)

 

Volvo Open 70

Length - 70.5 feet, (21.5 metres)

Width - 18.7 feet, (5.7 metres)

Depth - 14.8 feet, (4.5 metres)

Weight - 31,900 lbs, (14,500 kilograms)

Water Ballast - Centralised - 3520 lbs, (1600 kilograms)

Sail Area - Upwind: 3186 square feet, (296 square metres)

- Downwind: 7265 square feet, (675 square metres)

- Total: 10,451 square feet, (971 square metres)