A NEW RULE

The new class of Volvo Open 70s are in fact only about 2 metres longer overall than the Volvo Ocean 60s, but that is where any similarity ends. The waterline length of a Volvo Open 70 is approximately 4.2m longer than a VO60, the mast stands at 31.5m (103ft) above the water, some 4.175m (nearly 14ft) higher than a VO60 mast. This mast carries spinnakers up to 500 sq m, with a mainsail up to 175 sq m. This gives a downwind sail area 62 per cent greater than a VO60.

All this is on a boat with a sailing weight at least 2,000kg lighter than the VO60s at between 12,500kg and 14,000kg. To put this into perspective, an America’s Cup Class yacht tops the scales at 24,000kg, but has a downwind sail area only approximately 6 per cent greater than a Volvo Open 70! Of this weight somewhere between 6,000kg and 7,500kg can be found in the keel fin and bulb, ensuring a low centre of gravity for safety – righting moment for speed.

Such statistics are only achievable through the Volvo Open 70 rule allowing teams to utilise the latest in technology. Where as the VO60s relied on a fixed keel and 2,500kg of water ballast stored to windward for their stability and ability to carry sail area, the VO70s are able to cant the entire keel 40 degrees out to the windward side. This produces tremendous stability, similar to the current America’s Cup Class, but with a boat that weighs 10,000kg less. The canting keel uses hydraulic rams to force the keel and its bulb over to one side of the boat; the bulb, all 7,000kg or so of it, is actually well out beyond the side of the boat when the keel is fully canted.

Stability of the Volvo Open 70 is further enhanced by the use of composite rigging, rather than stainless steel rods, which reduces the weight of the rig. Such rigging also helps toughen up the masts as the ultimate failure loads of this rigging is far higher than that of the stainless steel rods they replace.

The construction of the boats is also very different, as much has been leaned since the VO60 (then the Whitbread 60) rule was written in the early 1990s. The entire structure is now built from carbon fibre with lightweight honeycomb core materials. Within the strict construction rules, this produces a hull stiffer and lighter than the VO60s, yet as tough and resilient, to ensure they can cope with the constant pounding of the sea as the VO70s hurtle across the seas, jumping from wave crest to wave crest.

The resulting yachts have already proven the potential of the class. Spain’s movistar quickly showed this with a new 24 hour record of 530 miles, at an average of 22.09 knots. This was during the delivery passage from the builders in Australia, beating the previous record, held by Mari Cha IV, a schooner twice movistar’s length. The dock talk is that the 600 mile day is only a matter of time for these ocean racing thoroughbreds.

Clearly, with such high speeds, loads also increase, and the safety of the competitors was never far from the rule writers minds as the rule was taking shape. Many of the chapters of the rule are dedicated to safety.

One highly visible safety requirement is the self-righting test, where each team must demonstrate that, without the need for outside assistance, the yacht can be righted from a 180 degree capsize (without the mast in), using the canting keel mechanism alone, with the skipper and two crew members inside the up-turned hull. This has now been completed by all the teams, and all agree it was a disconcerting, but valuable lesson. The position of watertight bulkheads, a sacrificial bow and minimum safety factors should the keel have a high speed impact with a passing whale or debris for instance, are all other examples of the thought that has gone into safety elements.

Both above and below decks the rule also tries to ensure that a minimal level of comfort is afforded to the crew. Below deck, there is a requirement for an enclosed heads (toilet) compartment, so that there is some privacy onboard. The galley is of a height and size to ensure it can be used comfortably by the crew, and a dedicated media station, separate from the navigation station, is required, to ensure that the footage gathered by each team is sent to race headquarters from a stable position, rather than from a laptop perched on a knee or the corner of the navigation station.

As you move above deck through the companionway there is plenty of protection from the constant onslaught of water. The spray dodger covering the entrance is required to be solid and to provide the crew with some protection from the raging seas. The freeboard (height of the deck above the water) has also been raised significantly from what would normally be seen on a boat of this size. This should reduce to some extent the amount of water reaching into the cockpit, although at the speeds we have already seen, not much is going to stop that!

Inside the spray dodger there is a water tight companionway hatch. Along with all the deck hatches this must comply with International Standards, ensuring that water can be kept out of the accommodation area below in the event of a severe knock down or inversion.

Above the deck the mast extends skyward to approximately 2.3m (7.5 ft) short of an America’s Cup Class mast (inshore boats around 16 feet longer with 18 crew on deck). Surprisingly these masts are only 60 kgs heavier than the VO60 masts, even though they are approximately 17 per cent taller and carry considerably more sail on a much more stable boat. This is largely due to the materials permitted in their construction and they are still considered to be very robust.

The sails hoisted on this mast are not only larger than those hoisted on a VO60, but are designed to perform in different conditions. The faster a boat moves, the further forward the apparent wind angle becomes. The crew on a VO70 will spend the vast majority of their time looking into the wind rather than feeling it from the side or behind. The sails, therefore, need to work well with the wind a long way forwards. Even the spinnakers will be relatively flat, and the days of symmetrically shaped spinnakers are well and truly dead for the VO70s. These large, flat, asymmetric spinnakers can either be set from the end of a spinnaker pole or from the tip of the 1.82m (6 ft) bowsprit, rigidly fixed to the bow of the boat, making the already aggressive plumb stem look even more forbidding.

While the design of the sails has changed, so has the number each team are allowed to use. No more than 24 sails shall be used throughout the race, compared to 38 for the last Volvo Ocean Race, with no more than 11 sails (excluding storm sails) on board at one time compared to numbers of around 15 frequently seen on VO60s. This means that each team must develop sails that are not only fast, but have a wide range of optimal conditions in which they can be used, often in a variety of configurations, and which last well.

Sails and equipment has to be controlled and maintained by a core crew of nine compared to 12 for the VO60s. This adds another level of complexity for the teams, as they must establish systems and methods of running their VO70 as fast as they can, while the small crew remains in control and able to deal with changes in weather. The need for sleep aggravates this problem, reducing the crew on deck to perhaps five in total for much of the time.

Whilst the boats are probably the most technically advanced to race around the planet, the organisers and rule writers were always keen to try and keep costs under control, to ensure that sponsors got as big a return for their investment as possible. One of the most expensive options previously available was two boat testing followed by using just one boat for the race. This approach was used with varying degrees of success in previous races, but is universally accepted that it allows allow for big steps to be made in optimising the race boat.

Now, when a team commits to build a VO70 they are issued a Volvo Open 70 Hull Number. Once a team has been issued this number for a boat they must enter that boat in the race. This means that any team which decides to go down this route must enter their boats in the race, meaning that much of the time two boat testing must also be spent getting both boats race ready.

With so many developments appearing and being refined within the VO70 class, the organisers are hoping to see much that is learned on these boats during the race filter down to weekend racing boats and cruising boats. Hopefully this will help all sailors to enjoy this sport further, in the knowledge that systems and equipment have been tested and developed in the most extreme of environments, by some of the worlds best sailors, on some of the most extreme ocean racing machines.

We asked for the comments of five of the world’s leading designers. This is what they had to say.

Bruce Farr

“The new breed of boats will certainly be high performance boats, but with the introduction of in-harbour, around the cans racing, they will also need to have a more rounded performance. Compared with the Open 60 fleet, these boats will see a good deal of upwind sailing which will have a significant influence on their overall design.

“I’d expect the new boats to end up somewhere between an Open 60 and one of the modern style seventy footers but with the upwind ability of a VO60.

“Keeping the crew secure will be an important issue, especially at speed and with hull shapes likely to include plumb bows, the new boats will probably have more freeboard forward to keep the boats dryer and to provide more reserve buoyancy.

“To get the best out of these boats, designers are going to need to strike the right balance between safety, crew fatigue and the boat’s performance. The last generation of VO60s were, at times, right on this edge. Just as an Open 60’s potential performance is often limited by the ability of the one crewman, VO70s will also be short on manpower for the amount of sail that they can set. The result is that other sail handling systems may be used to ease the handling issues.”

Hugh Welbourne

“There’s plenty of scope for a range of styles and the particular characteristics that a designer may go for will depend more on basic issues like routing and the team’s sail programme. Designing a boat that excels through a particular range of wind angles may leave gaps in the overall performance of the boat. Configuring the rig will be an important key in making the best use of the sails. From there on the hull will be designed to match.

“The point is that a designer can’t do anything in isolation. The relatively small number of crew means that these new boats will be in a cross over area, in many ways you can consider them to be neither single hander nor fully crewed. These boats will certainly be quick but there’s a trade off between increasing the performance and making the boats harder to sail. You don’t stand up to waves coming down the deck at 30 knots so crew protection will continue to be an important issue.

“Providing more protection for the crew, albeit at the cost of more windage and hence potential drag, might help to extract better performance from the crew.”

Rob Humphreys

“Creating a new design for this race starts with an accurate weather model. Initially you need to establish the amount of upwind and downwind sailing that can be expected along with a feel for the proportions of light and heavy airs. From here a designer can then start to work on some of the basic ratios given a target displacement.

“The first stages of a velocity prediction programme can then be created. The race course is then broken down into several parts which allows the sail development programme to follow.

“The waterline beam of a boat is a big issue as it provides one of the links between stability and wetted surface area. For example, a boat optimised towards downwind sailing or light conditions might have a narrow waterline beam with less wetted surface area.

“There’s no doubt that the change in the rule for the Volvo Ocean Race was inspired at least in part by the success of the Open 60 class. The overall concept for the next Volvo Ocean Race was to have more exciting, faster boats. Even multihulls were considered at one stage. But while the Open 60 class might have been part of the initial inspiration, the new VO70s will be very different boats.

“The new boats look like they will have a lot less drag than an Open 60 with less wetted surface area which will mean that they will be narrower boats and not so brutish. But with their full crews, the new boats will be driven a lot harder than the Open 60s.”

Rolf Vrolijk

“Developing a new rule leads inevitably to a compromise between encouraging maximum performance and achieving a good close race. To encourage the development of an exciting fleet of boats that can deliver an impressive performance, the rule makers need to allow designers the flexibility to experiment with more options and create innovative boats. The problem is that to ensure a good close race they need to tighten the design limits and restrict the areas of development.

“Creating a new rule is always more difficult for the rule makers than it is for the designers when it comes to safety. It is the rule makers who have to not only decide what the limits are, but have to second guess the potential loop holes. The preparation time for the next event is very short compared with the last race so this may mean that the rules end up being tighter initially to get close competitive racing, with a view to possibly relaxing them in certain areas for the second event.

“Time will be one of the biggest challenges for all, teams will have just one year to develop, test and refine their campaigns whereas last year many took three years to prepare. This shortage of time might encourage teams to work together both to save time and minimise the risk of being left out in the cold.

“As we saw in the last event, two boat testing is now essential where the main emphasis is on speed testing and less on crew handling.”

Merfyn Owen

“The new Volvo boats will probably have many features that are reminiscent of open class designs, such as swing keels, PBO rigging, etc. but that is likely to be where the similarities end. The rule that limits the static heel of the Open class boats to ten degrees is one of the biggest influences in their design. There is no such rule in the new Volvo class. As such we're likely to see more reliance on the ballast package for stability, which means narrower boats, probably with single rudders.

“Beneath the external differences each team will have placed their own emphasis on offshore/inshore performance to gain the maximum points score. That, along with the different weather/routing analysis and the experience of the different sailing teams, will ensure a ‘beneath the skin’ difference in all the designs.

“One of the major challenges of designing these boats, as with the Open 60s, will be balancing speed with control and ‘handleability’. The narrower beam and stopover ports of the Volvo, as opposed to the non-stop around the world race, will make this judgement more difficult. Is the fastest sail plan in the tunnel, the one with the lowest drag and is the tank-tested hull the one that the sailing team would choose? The crucial interaction between the designers and sailors will be one of the deciding factors for the team that wins the next Volvo, along with of course, time on the water.