Features November 1, 2003 Issue

Offshore Log: The Volvo Open 70

This new class of round-the-world racers has just been introduced. The boats will be designed for even more speed than their 60-foot predecessors, but also engineered for more safety.

by Nick Nicholson

PS editor at large Nick Nicholson is part of the Rule Management Group for the Volvo Ocean Race. In this article, he discusses safety features of the new Volvo Open 70, the carbon fiber, canting-keel hotrod that will be used for the 2005 Volvo Ocean Race.

This conceptual drawing of a Volvo Open 70 gives an idea of the scale and power of these boats.

----------

In November 5, 2005, an elite fleet of racing sailboats will depart a southern Mediterranean port, bound on a 31,000-mile odyssey, racing around the world in the Volvo Ocean Race. These 70-foot sloops—the Volvo Open 70s—will be the fastest offshore monohulls of their size ever built.

At about 26,000 pounds, they will also be among the lightest big ocean racers ever conceived. With their huge sail plans—a masthead 100 feet off the water, mainsails of 1,880 square feet, masthead spinnakers of 5,380 square feet—these canting-keel boats will have power-to-weight ratios more like racing motorcycles than oceangoing sailboats.

The nine to eleven men and women who make up each crew will be the best and toughest sailors on earth. And ironically, the thought and planning that have gone into the development of this class will make them some of the safest sailors on the planet.

Ocean racing is always a risky endeavor, and that will not change for the Volvo Ocean Race. What is different about the Volvo Open 70 is that an inordinate amount of effort has gone into creating a boat that is not only blindingly fast, but as safe as an ocean racer can be.

Volvo is an inherently conservative company whose success as an automaker is irrevocably linked to safety issues. The concept of a boat with cutting-edge performance may not seem to fit in with a company known for preoccupation with safety. A closer look at the Volvo Open 70 rule, however, reveals an underlying theme: creating an ocean racer that is as safe as it is fast. This is a significant difference when compared to other high-performance sailing craft. How designers reconcile the safety requirements of the rule with the demand for high performance will be a key to the success of the Volvo 70.

There are two basic elements to safety for any offshore boat: the ability to stay afloat in the event of serious damage to the hull, and resistance to capsize (plus its concomitant: the ability to self-right in the event of capsize).

Watertight Integrity
Oceangoing boats run a perpetual risk of collision with floating objects: trees, shipping containers, and ice. On our voyage around the world in Calypso, we stayed in temperate and tropical waters, with no risk of collision with ice. Shipping containers were a constant concern, however, as were other forms of floating debris.

While we were sailing from French Polynesia to Tonga, a ship lost several hundred containers overboard—a more common occurrence than you may imagine—a few days ahead of us, almost directly in our path. There was no way to know how many of these were still afloat (even a full shipping container is usually buoyant if it's watertight) along our route.

Likewise, in the Indian Ocean hundreds of miles south of Bangladesh, we passed huge floating trees and logs, some 40 feet or more in length and two feet in diameter, which could sink almost any normal cruising boat. These had washed down rivers during flooding, and could survive, just awash and almost invisible, for years.

It's one thing to nudge up against a floating object at a knot or so (think of impacts you may have had during poorly executed landings alongside a dock), and quite another to hit the same object head-on while traveling 25 knots.

It's pretty much impossible to design a high-performance sailboat that will survive major impacts without damage. After all, even the steel, "unsinkable" Titanic proved no match for an iceberg. The Volvo 70s will, almost inevitably, encounter ice in high latitudes. The risk of collision is real.

The Volvo Open 70 rule requires subdivision of the hull into a series of at least six watertight compartments, on the theory that impact damage is likely to be localized in a collision.

Four of the watertight compartments are in the forward part of the boat—the area most likely to be damaged. A diagonal collision bulkhead is the first line of defense, creating a sacrificial bow section outside the main structural part of the hull. In the last Volvo Ocean Race, a collision between two of the boats while racing, during an inexplicable port/starboard incident, showed that a collision chamber could provide some degree of protection.

Each movable appendage—including the canting ballast keel—must be in its own watertight compartment, so that damage to the appendage will not compromise the watertight integrity of the hull. In the case of sliding foils such as daggerboards, the appendages are likely to be housed in open-top trunks which go all the way to the deck, similar to those seen in Open 60 class boats (see photo, next page).

Within the hull, the watertight bulkheads must have hinged doors that can be shut within five seconds, and fully dogged in less than a minute. To prevent crewmembers from being trapped below, there must be direct access to the deck from inside most watertight compartments.

There are other unusual characteristics related to watertight integrity. The first is the requirement for a watertight cover plate for the mast opening in the event the mast goes over the side. This collar must be capable of being installed from the interior, so that in the event of mast and keel loss—certainly a worst-case scenario—you can block off the mast opening from inside an inverted, keel-less hull.

Just try to imagine yourself in this nightmare scenario: The mast has snapped in an uncontrolled broach at 30 knots, and the keel is wrenched off in the capsize that follows. You now have a boat that is in "stable two" position, and has a big hole in the deck where the mast used to be. (In practice, masts usually break well above deck, so the original mast boot is likely to still be in place.)

In the chaos below, you have to find and install the "mast hatch." At least you have a dedicated cover for the mast hole, and you know where it is and how it works.

Interestingly, there must also be at least one deck hatch that is at least six inches above the inverted waterplane for emergency exit in the event of capsize without having to force a hatch open against a head of water. We don't like to think about this kind of scenario, either, but it doesn't go away by ignoring the possibility.

Stability
Resistance to capsize has always been a major concern for any oceangoing sailboat, and the Volvo 70 is no exception. Resistance to capsize is also one of the more controversial subjects you can bring up, whether discussing racing boats or cruisers. How far should a boat be able to be knocked down and still come up on the same side?

For cruising boats, Practical Sailor has traditionally recommended a range of positive stability of 120 degrees for offshore boats. The problem for many cruising boats is that the designed range of positive stability is usually compromised by the time a boat heads to sea. Weight added to most cruising boats tends to reduce the range of positive stability by raising the center of gravity. Think of dinghies on deck or on davits, outboard motors on the stern rail, biminis, radars, wind generators—all these are well above the vertical center of gravity of the boat, and will reduce the range of positive stability as well as reducing initial stability. You may start out with a boat with a perfectly acceptable range of positive stability, but have a dangerously top-heavy boat by the time you actually leave the dock.

Racers are keenly aware of this problem, and avoid weight up high like the plague. Cruisers would do well to think a little more about it.

There is a perpetual conflict in the design of offshore racing boats: the desire for sail-carrying power in a breeze—which requires a fair amount of stability from some combination of hull shape and ballast in some form—and the desire for minimum wetted surface and lighter displacement both to reduce total resistance in lighter conditions and speed up acceleration in all wind conditions.

The Volvo 60s used in the last Volvo Ocean Race derived much of their sail-carrying power from water ballast, which has a function similar to putting a lot of crew weight on the rail. Of course, in a fairly shorthanded ocean race it isn't practical to have a lot of crew sitting on the rail—people have to eat, sleep, and sail the boat in shifts.

The downside of water ballast is that it increases the boat's displacement when in use, which can have the effect of slowing acceleration. Big water ballast systems also require heavy, fairly complex transfer systems.

The new Volvo 70s will derive a lot of their sailing stability from a canting keel. To put it simply, the keel fin and bulb may swing through an 80-degree arc (40 degrees each side of centerline). This is done with big hydraulic rams which are capable of holding the 9,900-pound keel bulb (plus fin) at any angle. Canted 40 degrees to windward, the bulb will give incredible righting moment to the boat. Canted slightly to leeward in extremely light air, the boat can be heeled to keep the sails full.

For safety reasons, two independent methods of canting the keel are required, each capable of holding the bulb at any position throughout its arc. In addition, there must be a quick-release system which allows the keel to swing back into its normal position.

A huge amount of thought has gone into the redundancy requirements for canting keels. These will not be inexpensive bits of engineering, but a lot of that effort will go directly into structural engineering applicable to other offshore racers and high-performance cruising boats. It will not be wasted money.

The Volvo Open 70 rule requires a minimum angle of vanishing stability of 115 degrees. This angle will be calculated with all appendages in their worst possible positions—the ballast keel fully canted to leeward, for example.

It will be interesting to see exactly what hull forms develop to meet this difficult requirement. Although 115 degrees may not sound like a big deal, it's going to be a lot for a light-displacement boat with a canting keel.

Self-Righting Test
Here's a scary one for you. Before certification as a Volvo Open 70, a boat must pass a self-righting test. This is not as innocuous as it sounds, and it's bloody important.

This is what we're going to do: First, we'll pull the rig out of the boat, and seal off all openings in the deck. Then we're going to turn the boat over. Not just heel the boat, but capsize it to a fully inverted position. This will probably be done with a crane and straps to roll the boat over. Now we have a fully inverted boat with the keel and rudder sticking up in the air.

Then the fun begins. The skipper and two members of the crew have to enter the boat (remember the hatch that's above the inverted waterline?), and from the inside, turn the boat right-side up. The only device they can use for this exercise is the movement of appendages, primarily by canting the keel to one side to tip the boat. They can't flood compartments to heel the boat to assist in this exercise.

Obviously, this is going to be a test of the skills of the designers and engineers, as well as the resolve of the crew.

While writing this portion of the rule, we half-seriously discussed requiring the designer to be part of the self-righting crew, but decided that it was more important to have someone who was going to sail the boat do the hard work.

Virtually everyone has seen photos of inverted ocean racers, keels pointed to the sky. This is not the kind of image Volvo wants to project. Proving that a boat can be righted by the crew from complete inversion is consistent with Volvo's concept that the boats can be both very fast and very safe.

Personal Safety
Most sailors who die in the ocean are lost after falling overboard. Anyone who has sailed offshore realizes just how difficult it would be to recover a crewmember lost overboard, even in the best of conditions.

Unfortunately, people usually go overboard in the worst conditions, not the best. Recovery is a hard enough job in a cruising boat going six knots. Imagine falling overboard from an ocean racer going 30 knots in 20-foot seas.

The International Sailing Federation's Special Regulations governing offshore and oceanic racing have for years been the offshore sailor's guide to boat preparation and personal safety. For the Volvo Ocean Race, these regulations have been taken even further, with modifications to the Special Regs designed to further enhance personal safety. Here are some examples.

Safety harnesses used in the Volvo race must be equipped with crotch straps and reflective tape, and both ends of tethers must be equipped with snap hooks for quick release under load. Spare tethers for 30% of the crew must be carried, as well as one complete spare harness.

Life jackets must be inflatables—no rigid flotation—and must be equipped with crotch straps. Inflatable life jackets are required in recognition of the fact that they are more likely to be worn in extreme conditions than more bulky units with rigid flotation.

One of the more interesting personal safety requirements is a "constant wear" survival suit for each member of the crew. These are intended as a cross between offshore foul weather gear and conventional immersion survival suits.

Conventional survival suits provide good protection when you're in the water, but are awkward to don and severely limit mobility. The constant wear survival suit is intended as a set of working foul weather gear as well as an immersion suit. It will almost certainly be equipped with a high-performance inflatable life jacket.

These suits may be fitted with secondary closures that convert it from foul weather gear to survival suit. They must have large areas of reflective tape, and may integrate other items of equipment such as safety harnesses, life jackets, whistles, and lights into the design.

There is not much available at this time that exactly meets this specification. Volvo hopes that foul weather gear manufacturers will come up with a new type of survival clothing to solve the problem—a solution that will be available to offshore sailors in general, not just elite offshore racers.

Another personal safety solution that has immediate implications for offshore cruisers is the requirement for man-overboard locator beacons, with on-boat direction-finding equipment. These were first required during the last Volvo Ocean Race, but we expect that more sophisticated solutions will appear for the next race.

Essentially, each crew member will wear a small radio transmitter which will be activated either manually or by immersion to a certain pressure. Permanently-mounted direction finding equipment on board will lead the boat back to the man or woman in the water.

While this equipment already exists, there is still a lot of room for improvement. Both the transmitting and receiving antennas can be functionally limited by high seas—just when the equipment is likely to be needed.

For the typical cruising couple, refinement of this type of location system would be a huge relief. Sailing double-handed offshore, only one person is on deck a large percentage of the time. If that person goes overboard while the other is asleep, it could be hours before the off-watch crew knows there is a problem. By then, it may be too late.

Another required piece of personal emergency gear is a remotely-operated man-overboard button at the helm station. This button will activate an instant waypoint on the belowdecks GPS, saving invaluable seconds in an emergency. No one will have to rush to the nav station to hit the button on the GPS.

The huge advantage of this for cruising sailors is obvious. Rule number one in a man-overboard situation is to keep the victim in sight. Running below for even a few seconds to hit the MOB button can take you a hundred yards away from the person in the water. One wave of separation from the boat is all it takes in severe conditions to lose sight of someone in the water.

Personal Training
To makes sure that every boat in the Volvo Ocean Race is properly equipped, the race organizers will supply an extensive medical kit. It is required that at least two members of the crew for each leg of the race have current certification sufficient for first-provider care for accidents or other medical emergencies.

Very few cruising boats have properly thought-out medical kits, and disappointingly few cruisers—other than medical professionals—have the skills to properly use what medical supplies are on board.

The Volvo Race requires two trained persons on board in case one of them is the person injured or sick. If only one half of a cruising couple has any medical training, you have a 50-50 chance that the trained person will be the one requiring attention in a medical emergency. These are bad odds.

Throughout the US, the American Red Cross and other organizations offer low-cost medical emergency training such as CPR, first aid, and first responder care. If you and your significant other are headed offshore, first head for a few days of emergency medical training. It's just as important as learning to sail.

Conclusions
Sailing offshore at speeds of 25 knots, pushing a boat as hard as possible no matter how bad the conditions, is about as risky as offshore sailing can get. For Volvo, meeting the seemingly contradictory goals of high levels of performance and high levels of safety is seen as a challenge, not as an obstacle. In the design of the new Volvo Open 70, Volvo has upped the ante to a level meant to be the ultimate challenge for designers, builders, and sailors.

Comments (0)

Be the first to comment on this post using the section below.

New to Practical Sailor?
Register for Free!

Already Registered?
Log In