Eric Hall on America's Cup Heritage - Part II

It’s 1958 and the J Class has been gone for over 20 years. In the second part of a personal look at the heritage and modern history of the America’s Cup Eric Hall remembers his first flirtings with the new bright young thing … the 12-Metre. (Read Part I here.)

The 12-Metre era was the beginning of a long family association with the America’s Cup. It began with my father, who was good friends with designers Rod and Olin Stephens and Jim McCurdy who, at Phil Rhodes Yacht Design, was working on the designs for Weatherly for the 1958 defence. My older brother Ned crewed on two successful defences: 1962 as bowman on Weatherly and as port tailer on Intrepid in 1967. My own America’s Cup summer was in 1970 as project engineer on the Britt Chance redesigned Intrepid.

My younger brother Ben, perhaps our family’s best sailor, never did a Cup campaign. But later as Hall Spars became a big player in America’s Cup rigs, Ben’s role was huge, being the company’s contact for all our Cup customers. After Oracle saw his very sophisticated A-Class wing mast that he carefully built in his basement, they convinced him to sell it to them. Russell Coutts told me later the A-Class tests with the wing by Oracle’s Glenn Ashby and others convinced them to build the huge wing mast they used to win the 2010 Cup. My son Tim also played a role managing our Holland affiliate’s America’s Cup IACC rig work.

The demise of the J Class followed by the trauma of the Second World War had led to a 20-year hiatus for the Cup following Ranger’s defence of 1937. It was not until the mid-1950s that New York YC commodore Harry Sears and friends of his at some British yacht clubs decided that the Cup must be revived, this time targeting the new biggest boats in town: 70ft 12-Metre yachts. But twelves were deemed not seaworthy enough to sail to the challenge waters ‘on their own bottoms’ so all agreed to eliminate that requirement and the Deed of Gift was changed. Twelves were regularly racing on both sides of the ocean so keen interest was immediate.

1958 Defence
​As in 1937, the NYYC group had trouble getting a syndicate together. New Jersey shipping magnate Henry Mercer stepped in and agreed to fund a boat to be named Weatherly. Chandler Hovey did likewise, agreeing to build Easterner in Marblehead. Things eventually came together for the NYYC and Columbia was also built. The fourth 12 competing that year was Vim, built in 1938 but now stripped down to the barest essentials in terms of equipment and, with Bus Mosbacher at the helm, she would certainly keep her new rivals on their toes. (Turning his older brothers green with envy, Ben, aged 12, got to sail a race on Weatherly in the New York Yacht Club Cruise of that year at the invitation of future America’s Cup Hall of Famers foredeck boss Vic Romagna and skipper Arthur Knapp).

All these twelves were made of wood, the most advanced of which was Weatherly with laminated wood epoxy frames built at Bill Luders’ yard, specialists in moulded plywood construction. Once, while visiting the Luders operation, a shop hand gave my brothers and me our first cans of two-part epoxy glue, a big help tinkering on our Thistle and wood Flying Dutchman.

The hulls were predictable. They all looked like the Js of 1937, with beautiful flowing lines both above and below the water. The only exception was that Easterner had a clear ‘corner’ at the lower end of her rudder’s trailing edge.

Materials-wise the biggest change was the use of synthetic Dacron sailcloth instead of the Egyptian cotton used by the Js. It was lighter and relatively unaffected by moisture. Rig-wise, the 12s already had aluminium masts; their rigs remained pretty much state of the art all through the 12-Metre era, with a handful of exceptions.

The biggest improvement was the use of streamlined shrouds from aviation technology that predated even the 30s on the high-speed Gee Bee, Supermarines and other racing aircraft. Basically round stainless steel was flattened into an oval with a roughly 3:1 thickness ratio. The shroud ends were left round and then threaded for fitting attachments.

As we touched upon in Part I, right from the get-go in 1957 the 12s also had aluminium spinnaker poles, a handful of which were soon being built by Grumman Aircraft made using early-stage aluminium honeycomb construction.

By 1964 designers Sparkman & Stephens had added a great deal of sophistication to their latest 12-Metre Constellation's masts and booms. At the time high-performance dinghies all had bendy masts and booms to give more sail control through varying conditions. The sailmakers were pushing the twelves in the same direction and the Constellation designers responded.

Adding any more bend to the relatively weak weld-tapered aluminium upper third of the 12-Metre masts risked breakage. The solution: design the upper third of the masts in rolled and welded higher-strength titanium. Welding titanium must be carried out in an inert atmosphere so the work was done by special facilities in the titanium industry to extremely high standards. For the same reasons titanium booms were also constructed in a similar way, to meet higher bending stress requirements.

Ironically, while the titanium-tipped masts were design-strength and manufacturing marvels, the quality of mast-fitting design, especially at the upper spreaders, was poor. During the New York Yacht Club Cruise in July 1964, Constellation’s mast broke just below the titanium-aluminium splice. The culprit: an undersized titanium spreader pin.

Although the titanium-tipped mast was repaired in time for the final trials Constellation stayed with their all-aluminium mast that by that point was highly tuned, fast and had the crew’s confidence.

Constellation started slowly in 1964, losing regularly to American Eagle. But after helmsman duties were handed over to top sailor Bob Bavier, Constellation went on to dominate, fulfilling the potential of her superior sail control with bendy spars.

1967 Defence
Three years later in 1967 the same rig designs reappeared on Intrepid. She lost her mast during the June trials, an occurrence first considered the fault of a brittle heat-treated titanium pin. A few other parts had also been made of heat-treated titanium, some of these also showing cracks in places. The problems ended when the parts were remade in more ductile annealed titanium.

When Intrepid and Constellation both lost their rigs on the same July day a month later (and almost exactly three years to the day after Constellation had broken hers in 1964) in fresh winds in Buzzards Bay, Intrepid’s skipper Bus Mosbacher was in no mood to listen to any more speculation about the rig failures.

My brother Ned was in the windward tailing position when Intrepid’s boom crashed to the deck near him when the mast went. ‘Bus was really upset,’ he recalls, saying Mosbacher minced no words this time, insisting Olin Stephens not only tell him exactly what happened, but also what the plan for the permanent fix would be.

Stephens admitted that, in hindsight, the designs were bad because they didn’t properly consider the bending and compression loads on the spreaders that were installed pitched downward to minimise windage when heeled. The spreaders on both boats just folded up, probably the real problem on Intrepid’s earlier failure and Constellation’s three years before. Mosbacher’s demands were met and bombproof spreaders were quickly made and installed with no pitch-down angle. There were no more mast problems in ’67. In ensuing years spreaders have been regularly installed pitched down, even on offshore racers.

Two factors ensured almost no further similar problems:

• Mast designers and their engineering tools were both getting much better.
• Design details were becoming an ever-higher priority.

1970 Defence
​In 1970 designer Britton Chance Jr was contracted to redesign Intrepid. Olin Stephens was designing a new boat and one could only expect it would be faster than the 1967 vintage Intrepid.

So the William Strawbridge-led Intrepid syndicate’s charge to Brit was clear: take a no-holds-barred approach and try every conceivable idea for improving the boat. Brit was a perfect fit because his intellectual curiosity was boundless – probably stemming from his father, Dr Britton Chance Sr, a world-renowned bio-physicist.

I guess it’s fair to say that as a result the 1970 Intrepid project went a little nuts with materials and, for good and ill, as project engineer I was in the thick of it.

In the mid-1960s, after graduation from the University of Michigan, I had taken a job at Grumman Aircraft, where, as previously mentioned, I was first introduced to some early composite technologies including boron-epoxy structures.

At the same time I was working with Brit Chance on the side helping him with Chancegger, Baron Bich’s design trialhorse for the eventual French challenger France. (The ‘Egger’ half was the Swiss builder he contracted. With their names on the boat Bich figured he’d get their best work.) Brit knew that I was working on advanced composite structures in the Grumman F-14 fighter programme so the first thought was applying that where we could to Intrepid’s spars and related components. It would be a full-time effort and in late 1969 Brit hired me to do it.

The F-14’s design called for a horizontal stabiliser with a boron-epoxy skin, the first advanced composite production article in aviation history. Boron has great properties, still exceeding the best carbon materials in tensile and compressive strength and at least equal in modulus of elasticity. But boron was, and still is, prohibitively expensive. A pound of carbon at the time was also expensive at US$300, but boron was many multiples of that.

But fighter jets could justify it with the potential weight savings. Grumman graciously agreed to donate a boron/carbon/ honeycomb spinnaker pole to Intrepid and, later, Valiant for the Cup. No cost was ever revealed for the poles but the number was easily in six figures, according to reliable sources. The new poles weighed 39lb where existing poles weighed 89lb. Intrepid’s pole, now on display at the Herreshoff Museum in Bristol, is arguably still the highest-tech spinnaker pole ever built.

A hybrid aluminium/boron/carbon/ honeycomb boom was also made but sideways bending problems took too long to solve and it was never used in a race. In an interesting historical irony, the J Class designers, who worked hard at bending booms sideways for better sail shape in the area just above the boom, probably would have liked it!

A boron shroud programme was initiated when Brit found a Washington DC Beltway start-up that could make rods using unidirectional boron with a magnesium (instead of epoxy) matrix. Boron stays would have been a quarter of the weight of Intrepid’s stainless shrouds, providing a huge advantage as stays were not part of the rig minimum weight rules.

The programme called for creating lenticular sections to be bonded to special titanium ends. When the 1m test sample easily passed its test programme, a first (V2) shroud was ordered. The programme cratered when the full-sized shroud exploded into pieces well before it reached its design load in Grumman’s static test facility. We could only guess that the magnesium had too little give causing some fibres to load up before others, starting a simultaneous failure.

When someone introduced him to the metal beryllium which had the weight of aluminium and stiffness of steel, Brit immediately looked aloft. Although the sophisticated titanium mast tips that came with Intrepid were stronger than aluminium, they were no lighter and Intrepid’s mast VCG was above the minimum height, even with corrector weights placed at the butt to bring the mast up to minimum weight.

If beryllium was so stiff and light, Brit mused, why not replace some of the titanium aloft with it, matching the tube’s stiffness while bringing the VCG down to minimum height; subsequent calculations proved it would do just that and without any reduction in strength. It all worked as designed and the corrector weight to bring the mast up to minimum weight was now placed right at the VCG, yielding a mast with much better mass moment properties than our competitors’ spars.

The chemical milling removal of titanium in discrete areas and replacement of it with bonded 0.015in (0.4mm) beryllium sheets is a story in itself. Suffice to say that, though it certainly may have helped us win, it was a daily nightmare to keep serviced.

Because beryllium was even lighter than aluminium the syndicate also encouraged the manufacture of a bunch of beryllium fittings (gooseneck and headboard car among them). But beryllium is a ‘powder metallurgy’ material and, like castings, its brittle nature was not structurally optimum for primary, point-loaded yacht structures. The fittings broke in several cases and the beryllium fittings were never raced.

Even though exact figures were never revealed, rulemakers knew that these exotic materials would increase the cost of 12-Metre racing significantly and banned their use after 1970. Carbon did return in 1987 since by then carbon spinnaker poles were being widely built at higher but still reasonable costs.

Reading reference materials, it seemed as if Intrepid’s rig in 1967 had featured another first: streamlined titanium shrouds. In a quote about all the things Intrepid had going for her in 1967, Olin Stephens mentioned ‘streamlined titanium rigging’.

With great respect, I believe that Olin was wrong. I say this because in 1970 we inherited all Intrepid’s 1967 rig materials and the shrouds were all stainless steel.

In 1970 we had machined streamlined titanium V2-D3 shrouds but I always felt that, since the titanium shrouds were only slightly lighter but also slightly bigger, any performance increase was marginal at best.

In 1970 a major new rigging system was introduced by recent start-up Navtec. Now universally known by every sailor, Navtec’s rod cold heading process was revolutionary at the time. First, it allowed much simpler assembly of rigging, plus it had the added advantage of being almost bulletproof in fatigue. By contrast the previous rolled streamlined stays, with high-stress concentrations at their threaded ends, had a more limited fatigue life.

The price of the new Navtec product also compared favourably with other rod systems on the market at the time. We didn’t use it because we had already inherited rigging, but Charley Morgan did buy it for his 1970 defence candidate Heritage, launching Navtec’s meteoric rise in the yacht rigging business.

1977 Defence
​Through to 1974 most 12-Metre masts were made from the same oval section. In 1977 Ted Hood’s Independence team worked much harder on mast details than anyone before. Ted’s engineers and mast builders created rigs that were based around a multi-piece riveted and aero - dynamically optimised D-section. Adding to that they optimised their mast fittings for minimum windage and also carefully optimised their boom design.

A lot of this work also benefited their stablemate Courageous which went on to defend the Cup that year in the hands of ‘Captain Outrageous’ Ted Turner. The other contender, Enterprise, in the capable hands of Lowell North, was hard at work as well.

As John Marshall recalled recently, he and Lowell thought a smaller, higher aspect foretriangle would be faster. Marshall felt it was faster in straightline speed, but had an unanticipated flaw: since genoa overlap areas were the same regardless of foretriangle size, the space for getting this same amount of sail through the smaller foretriangle was an issue, slowing up tacks. Marshall believed this had a negative effect on Enterprise’s ability to be competitive in tacking duels, most notably with Courageous, with whom they otherwise felt they had equal straightline line speed.

During the 1970s 7075-grade aircraft aluminium, stronger than conventional mast aluminium 6061, was used to build some 12-Metre masts that proved stiffer in bending. Since it cannot be welded, 7075 masts were made in complex multiple riveted sections. But use of this alloy was shortlived, probably because of its susceptibility to corrosion in a salty atmosphere!

1980 Defence
​Through the years the twelves had been steadily increasing mainsail roach curves. But by 1980 they’d pretty much reached a practical limit, where any more roach resulted in unstable leeches. Enter the British contender Lionheart that year with certainly the most dramatic rig development in 12-Metre history: a permanently bent, fibreglass-tipped mast.

The British mast had, by 12-Metre standards, a huge permanent bend in its upper third. The idea was to add ‘roach’ (till that point unmeasured) to the leading edge rather than the trailing edge. It allowed more area and longer battens on a much more stable sail. Once the Aussies saw Lionheart’s rig they went to work themselves in secret and by Cup time they had their own fibreglass-tipped mast.

In light air they were formidable, winning the light-air ‘Sunset Race’ in the 1980 Cup finals before ultimately losing 4-1. Dennis Conner said at the time that this was the future of 12-Metre rigs. Rulemakers, in typical reaction to a really good idea, had other ideas. Henceforth they required mainsail girths to be measured, effectively killing the innovation.

1983 Defence - lost to Australia II
​In 1983 hydraulic jumpers were introduced on several boats, most notably eventual Defender Liberty whose port and starboard jumpers could be adjusted independently, allowing both fore and aft and sideways control of the mast. In the sixth race of the Cup Liberty’s hydraulics failed, preventing use of the system. Although she lost that race (and, famously, the Cup the next race), John Marshall said the hydraulic failure did not impact the result.

At Hall we built our first 12-Metre rig in 1983. On the rig, for French entry France 3, one of the experiments that was tried but didn’t work was the installation of a set of Teflon-lined curved tubes to take the place of halyard sheaves. The weight saving was impressive but function wasn’t – and we soon went back to sheaves!

1987 - Freemantle
​In 1987, the last year the America’s Cup was sailed in 12-Metre yachts, composites re-entered the picture. By now the ban on carbon poles was lifted (carbon poles were now common on boats all over the planet) and most of the 12s had them. At Hall we also made what was, I believe, the only boom with a composite structure. Built for Tom Blackaller’s San Francisco entry USA II, it was a carbon-aluminium hybrid with aluminium caps top and bottom and cored carbon sides.

Right after the 1987 Cup a complicated Deed of Gift Challenge was issued by New Zealand creating the famous Big Boat vs Catamaran Cup. Although it may not have been intended, it caused the demise of the 12-Metre yacht as the America’s Cup class of choice, leading to the creation of the new International America’s Cup class (IACC) for the 1992 Cup.