Power racing multihulls

World record attempts, although very different in character from fleet races, are races nonetheless. With three teams currently attempting fast power boat circumnavigations, there is definitely something of a rivalry involved. The teams involved are downplaying the competitive aspect of their mutual quest, but make no mistakeeach is extremely interested in how the others are getting along.

At the time of this writing, the only boat actually on the course is Stephen Shidler’s Revolution, which will have commenced her record run from Miami in early March, heading southwest for Panama.

The 60-foot trimaran out of San Francisco can be best described as a minimalist approach to high-speed passage-making. Shidler’s unique boat resembles an overgrown water-striderthose agile, water-walking insects that children like to chase along river banks. Her main hull is only 3.5 feet wide at the waterline, and even with a full load of fuel and provisions aboard she displaces just seven tons. Ultra-light displacement and "maximum speed for minimum effort" are the themes of an imaginative, highly professional program that has racked up 27,000 miles of sea trials in preparation for the main event.

Steve Shidler is a real estate developer and lifetime ocean sailor who has financed his record attempt largely out of his own pocket. A personable man who enjoys publicity, Shidler is delighted to talk about his ideas with journalists or anybody else, a refreshing change from the secrecy of some campaigns. He sees his quest as the launching pad for a new generation of super-efficient, long-range voyaging boats that will outperform sailboats and cost less to operate. I had the opportunity to check out Revolution in Miami shortly before the team’s departure, and will provide details about Shidler’s remarkable vessel and program bit later.

Second away should be Cable & Wireless, a rapier-slim 114-footer, largely sponsored by the giant British-based telecommunications firm of the same name. Described as a stabilized monohull, she is in fact also a trimaran, but with exceptionally small, truncated amas (outer hulls) located fairly far aft.

Official departure is currently scheduled from Gibraltar in April, and, unlike Revolution, Cable & Wireless will head eastward toward Suez. The design concept for this vessel is based upon an earlier 70-foot Nigel Irens power trimaran that presently holds a round-Britain speed record. This is a big boat/big budget program that aims to maximize exposure for an ambitious firm that is seeking to expand its global markets. There are 17 stops planned along the way compared to Shidler’s 11, so substantially higher passage speeds will be needed to maintain a record pace.

The third challenger, Sid Stapleton’s Global Victor, can, at present, be regarded as the dark horse of the field. Construction of the prototype Awesome 770 luxury catamaran is reportedly underway, and it may still be possible to depart San Diego by July 4 as planned. Stapleton lists 42 firms in the pleasure marine field that have donated products and services to his program. However, he admits, "I’m also looking for a company that wants to put its logo on the boat as title sponsor for $2 million." As with Cable and Wireless, the announced timetable leaves precious little time for sea trials prior to the record attempt.

Why power around the world?

The current transatlantic power record of 58 hours, 34 minutes was set by the 220-foot planing mega-yacht Destriero. Her 53-knot average can be credited largely to raw horsepower and was only made possible by mid-ocean refuelinga bit of a cheat in the eyes of some who felt that the venerable Blue Riband trophy should have remained with the famous liner SS United States, which did the run non-stop.

In contrast, the nuclear submarine USS Triton, which set the current round-the-world powering mark back in 1960, averaged only 13 knots for her 83-day, 10-hour voyage. Being nuclear powered, she did not, of course, need to refuel en route. In principle, this modest level of performance could easily be bettered by any number of contemporary vessels, including some of the faster diesel-powered containerships. The fact that it has not presumably means that no one with a suitable ship at his or her disposal feels that the effort and revenue losses would be worthwhile.

On the other hand, glory, cash prizes, and long-term sponsorships await those who win the Jules Verne trophy for breaking the round-the-world sailing record. No doubt this is why the current mark of 71 days set last year by the French trimaran Sport Elec is so much quicker than that of Triton.

Given that it would be no great feat to power around the world inside 83 days aboard a large, fast ship, why all the fuss about breaking this record? Of course, the real challenge stems from trying to better the record using a yacht-sized vessel, because anything shorter than about 300 feet will need to run at well over displacement speed to maintain a record pace. Naturally, the clock keeps ticking during the fuel stops, canal transits, and so forth; as anyone experienced in long-distance freeway driving knows, stop time wreaks havoc on the average speed. Professional motor racers understand that fuel management and fast pit times are the keys to race-winning performance, and those seeking round-the-world power boat records need to plan along similar lines.

Small offshore vessels face a stiff additional challenge when compared with large ships because they tend to be impeded more by difficult sea conditions. On a voyage of this magnitude, bad weather along the way is a virtual certainty. Potential record breakers need to develop craft that can maintain speed in adverse sea conditions, and to do so without burning too much extra fuel.

Multihulls make sense

The common theme in all three programs is a trimaran or catamaran configuration, for good reason. A very slender, elongated hull form currently represents the only energy-efficient way to escape the tyranny of wave drag and displacement-speed limitations. Properly designed multihulls can also reduce the added drag penalty associated with adverse sea conditions while offering superior ride comfort.

Although it’s true that offshore racing power boats routinely sustain speeds of 70 knots and more as they careen off waves in spectacular fashion, it’s also true that these monster deep-vee monohulls and tunnel-hull cats are unbelievable fuel hogs that can at best cover just a few hundred miles before tanking up. The logistical problems associated with crossing an ocean in a planing power boat are enormous. To take one around the world would be all but impossible.

The extremely slender hulls of a multihull vessel can circumvent the wave drag "trap" because, unlike normally proportioned hulls, the troublesome bow and stern sections together make up a much smaller fraction of the displaced volume. This means that the pressure fluctuations created when flow diverges and subsequently converges at the end of the slender hull are much less severe than for a wider hull of equal displacement. A very narrow boat will knife through the water with little fuss, even at two to three times its theoretical "hull speed" (1.34 x square root of waterline length in feet). This principle has been appreciated for centuries and has been used for all sorts of fast watercraft, from Polynesian outriggers and Greek galleys to contemporary rowing shells.

To obtain a substantial benefit, the length-to-beam ratio needs to be at least 7:1, but going as high as 18:1 pays added dividends. On the other hand, elongating the hull beyond about 18:1 brings diminishing returns because the increasing wetted surface drag offsets further savings in wave-making resistance. In addition, an overly narrow hull offers very little payload capacity because its skin surface area and structural weight become too great relative to the displaced volume. Length-to-beam ratios for the individual hulls of most practical multihulls fall between 8:1 and 14:1. Even so, limited load-carrying capacity is a common shortcoming, particularly since these boats often end up being built more heavily than their designers envisioned.

A comprehensive program

Steve Shidler has been pursuing the goal of long-range, high-speed power boat voyaging for about a decade now. In the early ’90s he built Endeavoura 40-foot trimaran powered by twin 27-hp Yanmar diesel outboardswhich he took across the Pacific from San Francisco to Sydney, Australia, setting two power boat distance and efficiency records along the way. Endeavour is literally the heart of Shidler’s subsequent 60-footer, Revolution, because the earlier boat was sliced up and expanded to create the new, larger hull. Endeavour was originally built by R.D. Boatworks (now out of business), while Dencho Marine in Los Angles handled the extensive modifications. Basic construction is cored sandwich using the Baltek DuraKore mahogany/balsa planking method. Skins are fiberglass, Kevlar, and carbon fiber, bonded with heat-cured epoxy.

What appears to be a bulbous bow on Revolution’s main hull is actually a wave-piercing feature designed to reduce pitching and heaving motions in a seaway. By keeping the boat’s direction of travel as close to a straight, horizontal line as possible, energy requirements are minimized and crew comfort improved. The bulbous bow seen on cargo ships have a different purpose: to reduce bow wave size by deliberately inducing wave interference. The principle would probably work if the 60-foot Revolution was designed to cruise at eight to 10 knots, not at 20 knots-plus.

Revolution’s hull lines were developed by Kvaerner Masa Marine, a naval architecture firm with extensive experience in wave-piercing hulls for the European fast ferry market. Morelli and Melvin, multihull designers based in Long Beach, Calif., handled much of the project engineering and on-the-water research and development work. The trimaran configuration is ideal for this ultralight wave-piercing concept because the amas (outer hulls) are only needed to balance the elongated main hull and can therefore be kept short and light. A sailing trimaran must cope with much larger heeling forces, so each ama must be sized to support the entire weight of the boat with plenty to spare200% buoyancy is typical. By contrast, Revolution’s amas, when fully immersed, each provide 5,500 lbs buoyancyjust 60% of the vessel’s half-load displacement. According to Shidler and his team of designers, this should be ample.

The amas are positioned far forward to prevent plunging when Revolution slides down large following seas. Cruising speeds in the 19- to 22-knot range will closely match the speed of open-ocean waves in many cases, allowing Shidler’s boat to surf for two to three knots of extra speed or throttle back for reduced fuel consumption.

The outboard sections of the cross beams that support the amas are telescoping, and contain hydraulic rams that permit 18 inches of vertical adjustment. This feature allows the trim (pitch) angle of each ama to be adjusted, and, more important, helps to compensate for the major weight loss that takes place as 1,200 gallons of diesel fuel, weighing 8,500 lbs, is burned off during a long passage. This weight loss translates to a 10-inch change in the main hull waterline.

In a cross-wind, the windward ama is normally raised to its highest position to minimize contact with the wave tops. In addition, both amas are fitted with hydrofoils, mounted like transom-hung dinghy rudders, that hoist the amas clear of the waves for additional savings on drag. Of course the foils are vulnerable to collision damage, and Steve Shidler is by no means sure that they’ll survive very far into the trip. However, thanks to swing-back mounts, they can take a severe hit without doing damage to the ama structure.

Revolution is propelled by a four-cylinder, 225-hp Yanmar turbo diesel that produces a top speed of 26 knots. She typically cruises at 20 to 21 knots on 160 hp. This represents a fuel economy of around 2.4 nautical miles per gallonunheard of for a four-person, long-range motor yacht running at this speed. Fuel-flow metering and speed/position data are fed into an on-board computer to optimize boat speed for the fuel load and distance remaining at any given time. As in auto racing, the idea is to finish in the shortest possible time and with the tanks almost dry.

Fuel management for the round-the-world attempt also extends into the realm of global logisticsselecting appropriately positioned ports with trustworthy contacts ashore who can facilitate quick turnarounds. The Revolution budget does not extend to sending advance teams to 11 far-flung ports, so the team is relying upon a network of friends and contacts. One team member, the well-known British offshore racer and boating author Dag Pike, has been particularly helpful in route planning. At age 65, Pike has made a career exploring the outer limits of ocean power boating. In fact, he arrived in Miami to meet Revolution by piloting a rigid inflatable boat 1,000 miles across the Gulf of Mexico from New Orleans.

Revolution’s compact engine room is the particular responsibility of Michael Rogers, a highly qualified marine engineer and commercial captain. To minimize weight, a compact 1.5-gph watermaker is used to top up a bladder-type storage tank holding just 14 gallons (with a scant five gallons stored separately as the emergency reserve). There are 300 lbs of food stores aboard and a small Winslow life raft, but no dinghy. As Shidler explains, every extra 100 lbs aboard represents a 50-mile loss or about 2.5 hours added to the circumnavigation time.

Media exposure is the life blood of this round-the-world adventure, so the fourth crewmember is Jack Tinsley, a Canadian video producer and professional mariner. The program has a web site (www.revolution98.com) for continuing updates on trip progress. The team expects to return to Miami in mid-May. Their progress can be tracked on the net.

Cable & Wireless and Global Victor

So far, the multimillion-dollar Cable & Wireless program appears quite publicity shy, but construction is supposedly well underway at the Vosper Thornycroft yard in Great Britain. Spearheading the effort are yachtsman/adventurer Jock Wishart (who will skipper the boat), designer Nigel Irens, logistics director John Walker, and Mike Piercy of the title sponsor firm.

One reason for the substantial size of this vessel is the size of the crew; Wishart and four professional sailors plan to share the adventure with 12 amateurs who will contribute $32,000 each for their berths. Cable & Wireless will be propelled by twin 350-hp diesels and is designed for a range of 3,500 miles. Cruising speeds will presumably be in the upper 20s. Launch date was originally planned for January and is now slated for March, with an April departure from Gibraltar scheduled.

Sid Stapleton’s Global Victor program involves an even larger, if somewhat shorter, vessel. The prototype Awesome 770 long-range, cruising catamaran carries 5,000 gallons of fuel and will make her record attempt with a crew of six aboard. With twin Caterpillar 3406E diesels capable of 800 hp each, she’s projected to burn a little less than 30 gallons per hour at her 20-knot voyaging speed. Stapleton’s route is similar to Shidler’s, but his San Diego departure postpones the uncertainties of Panama Canal transit to the final stages of the trip. Stapleton points out that "Global Victor is a luxurious motor yacht rather than a stripped-out racing boat. We’ll be sleeping on inner-spring mattresses instead of in pipe berths, and we’ll have steaks for dinner." Certainly it’s a sharp contrast to Steve Shidler’s creed of "minimum energy, maximum motion." But, of course, the difference is reflected in roughly five times the horsepower and fuel consumption to achieve comparable performance.

Progress of the Global Victor program can be checked at Sid Stapleton’s web site: www.sidstapleton.com.

Future implications

I must admit that I’m partial to the Shidler’s low-cost, low-impact voyaging philosophy. The prospect of a long-range, all-weather motor voyager that actually costs substantially less to buy and operate than a sailboat of a similar size is a tantalizing one. Two estimates on the cost of duplicating Revolution, one from a Florida yard and the other from California, both came in at around $350,000. Series production should, of course, reduce this considerably.

Shidler’s meticulous, professional approach to the record attempt and the fact he is already en route appear to put him on the inside track for a new record. The much larger Cables & Wireless will be running round-the-world in the easterly direction and later in the season. Whether these variables will improve her performance is, at this point, anyone’s guess. Global Victor appears to be bringing up the rear in terms of funding and preparation, but, with the largest, most ship-like vessel, Stapleton may still snatch the record, particularly if the others run into trouble.

What seems increasingly clear is the huge potential of multihulls as efficient, seagoing motor yachts. Trawler yachts are selling like hotcakes these days, and there’s no question that many are safe, comfortable voyaging boats. But few of these hefty monohulls can average better than eight knots on an extended ocean passage because fuel consumption skyrockets once they are pushed into the semi-displacement mode. On the other hand, 12- to 15-knot voyaging speeds are easily attainable by relatively low-powered multihulls. And in this speed range it’s certainly not necessary to sacrifice living space and comforts to the extent that Shidler has done for his record attempt.

The catamaran configuration is usually favored for multihull voyagers because it provides maximum living space and deck space within a reasonable overall length. Power catamarans don’t need the extreme beam of sailing cats and are sometimes no wider than conventional planing yachts of the same length. I found it interesting that every one of the dozen or so designers attending a weekend multihull symposium at the Strictly Sail boat show in Miami could not resist mentioning power multihull projects. Many in the industry as a whole now see power multihulls as the boats of the futurethe next big thing in pleasure boating. And as Steve Shidler likes to emphasize, "It’s still in its infancy. After 27,000 miles in Revolution, we’re still making big performance jumps."

Contributing editor Sven Donaldson, a former sailmaker, is a marine technical writer based on the West Coast.

By Ocean Navigator