Eric Hall on America's Cup Heritage - Seahorse, October 2017

America’s Cup-winning sparmaker, aerospace engineer and composites innovator and closely involved with America’s Cup technology for well over half a centruy, Eric Hall offers a little more insight into just how deeply that heritage runs.

Returning from the Bermuda Race in 1958, as our family cutter Nimrod V (ex and again Blitzen) was passing Block Island we were excited to see two America’s Cup contenders appearing out of the fog that was just burning off in the noon-day sun. It didn’t take us long to figure out it was 1938-built Vim (same year as Nimrod) practising with their trial horse Gleam. That was day one of what became for me over 50 years of sometimes obsessive interest and participation in the America’s Cup.

Following today’s America’s Cup, with the absolute highest level of equipment with hydrofoils and demanding composite structures, it’s fun for me to reflect on my own life and its participation in hydrofoil and advanced composite technology.

In 1958 my brothers and I were following 12 Metre news closely. Three boats were being built, Olin Stephens-designed Columbia, at the Nevins yard in City Island, Phil Rhodes/Jim McCurdy-designed Weatherly at Bill Luders’ yard in Stamford and Ray Hunt-designed Easterner at Graves in Marblehead. A fourth was Vim which had been sailing on Long Island Sound as a semi-cruising boat for years with the Matthews family.

Two others, Gleam and Nyala, had also been racing but were not entering the Cup campaign. A third, Nereus (née Northern Light and built alongside Vim in 1939), was taken out of mothballs to serve as a trial horse to Columbia. For the Cup trials Vim was stripped of extraneous equipment and was a deadly serious contender with Bus Mosbacher at the helm.

Luckily, as a Long Island Sound yachtsman himself, my father knew most of the players, both designers and sailors. During the New York Yacht Club cruise that year we got tours of all the boats on a lay day. The guy who showed us around Columbia was a very friendly 21-year-old MIT student named Halsey Herreshoff.

My father also worked at Grumman Aircraft where, with his considerable pull as ex-chief test pilot and now chief engineer, he had Grumman build some slick bonded aluminium/honeycomb spinnaker poles for Weatherly and Columbia (and, natch, one for Nimrod V).

That pull was to help my own efforts as chief engineer for Intrepid 12 years later in 1970.

During my early 1960s schoolboy years I worked for a company that built hydrofoil boats. Still a year or two away from grad school, I became fascinated with hydrofoils, observed everything I could and decided that I’d like to be an engineer because I wanted to design and build hydrofoil boats.

In the mid-1960s after graduation I also took a job at Grumman and eventually ended up on the F-14 fighter aircraft design team, in the small five-man Horizontal Stabiliser design group. Lucky for me the project was ambitious: it was to take advantage of the emerging boron-epoxy composite technology.

As earlier with hydrofoils, I was hooked again, this time by advanced composites.

The America’s Cup of 2017 in Bermuda drew my major fascinations together as never before. The America’s Cup is like that. But first let’s go back a little…

1930-1937: The J-Class era

The America’s Cup has always been about technology. The modern era of America’s Cup racing started, arguably, in 1930 with the advent of Marconi rigged J-Class yachts. With it came major technological developments, many of which had years-long impact. Although 1930 was almost 90 years ago participants’ relentless quest for better performance that year rivalled even the most technology-driven America’s Cups campaigns that followed and exceeded many.

The 1930s saw significant technology advances and the yachts were sailed by America’s best – well, really, east coast America’s best. Basically, there were New York boats and Boston boats. And most were built here in Bristol, a short sail away from Newport. Although many of sailing’s greats participated during those years, the dominant figure was Harold S Vanderbilt who was defending syndicate manager and helmsman in all three J-era Cups in 1930, 1934 and 1937.

His first J was Enterprise in 1930.

1930

Unlike today’s J-Class yachts with their sumptuous interiors, in keeping with America’s Cup yachts until that time, Enterprise was a stripped-out machine with accommodation barely adequate for the afterguard to go below for a cup of tea. Then, as now, windage, weight aloft and above-deck simplicity were high priorities.

Vanderbilt, in his two books about those years, Enterprise (1930 Cup campaign) and On the Wind’s Highway (1934 and 1937 campaigns), repeatedly stressed his near-obsession with windage and weight aloft. On Enterprise shroud chainplates as well as most of the winches and related sail-handling equipment were below decks. During the 1930 campaign even runner blocks were moved below deck with only the runner cable itself visible above.

While sailing, a ‘Black Gang’ of crew were below and rarely saw the light of day while the crew slept and ate aboard other support craft. Eventually enough people came to accept that it was too much to ask of a challenger, sailing across (as the rules demanded) to Newport with full accommodation, to then have to strip it all out to prepare for the summer’s racing in Newport. The rules were changed.

In late 1930 new rules were introduced to require ‘seven short tons of cabin fittings’ which included full crew and afterguard living spaces for future Cups. At the same time all but a very few operations (for example, centreboard hoisting) were moved above deck. Vanderbilt, with typical clarity, said he thought the new Js with their interiors had acquired a ‘simplified mobility’.

Enterprise, a ‘smaller’ J at 75ft waterline, could not survive the rule change and its negative impact on her stability and ‘was broken up and sold to the junkman’ after the 1930 Cup. Yankee, being a larger 87ft waterline J, did survive the increase in displacement with little or no apparent ill effects.

The advent of the J Class in 1930 put new rigours on sail handling and power and speed were increasingly in demand. As now, sailing on a J then was to experience first hand the enormous power these boats generated. Sail-handling systems such as multi-part come-alongs no longer sufficed. As a result, the pedestal winch was created, the ‘outstanding winch development’ of those years, according to Vanderbilt.

The first such winches were on Enterprise in 1930 with pedestals below decks connected to one or more drums above deck, as on the 12 Metre Cup yachts of 1967 and 1970 before similar rule changes moved them back on deck in 1974.

Such winches have been routine equipment on racing yachts ever since. The winches were the brainchild of Nathaniel G Herreshoff, ‘the Wizard of Bristol’.

As a tribute to their engineering, Super-J Ranger had 27 winches but only three were new. To give an idea of Herreshoff winch durability, some of Ranger’s winches came not only from Rainbow and Enterprise but also from Resolute, built in 1913, and, astonishingly, yachting’s all-time behemoth Reliance some 34 years earlier.

Luckily plenty of books have been written about Herreshoff. One can never mention him without emphasising how special a person he was. He was not only a yacht designer, but also his superb engineering prowess created steam engines, cars, planes and high-speed motorboats, to name just a few of his endeavours.

Duralumin (aluminium) mast

In 1930 Enterprise’s designer Starling Burgess was fascinated about the prospects of a lighter mast in Duralumin, a new material until then found mostly in aircraft. Despite its huge expense, he convinced Vanderbilt to order one. The mast weighed 4,000lb whereas her wood mast weighed 5,000lb. Vanderbilt considered it ‘the outstanding contribution’ to her performance.

A word about designer Starling Burgess. Like Herreshoff, Starling Burgess was a special individual. He not only designed yachts, he was the foremost rig designer of the time. Early in my career my boss at the time, Brit Chance, told me to read and prove I understood his paper on the subject. No one has ever written a more detailed and scholarly treatise on rigs. He was also a poet, car designer, classical music expert and a historically significant aeroplane designer. He built the first plane to fly in New England in 1910 and in 1915 won the Collier Trophy, to this day aerospace’s most prestigious prize. The sheer size of his biography, No Ordinary Being, tells it all. It’s the biggest book in my library.

Two wooden masts, a heavy version and a light version, were ordered as back-up. The Duralumin mast was designed by Burgess’s brother Charles, an accomplished mathematician and civilian engineer in the United States Navy, and built at the Glenn L. Martin aircraft factory in Baltimore. It was a dodecagonal (12-sided) circle made of formed Duralumin and riveted together with protruding round head rivets. Its diameter at the deck was just 45cm tapering to 20cm at the tip.

It was not ready when Enterprise was launched in Bristol in early May, so the heavy wooden mast, built at Nevins yard in City Island NY, was stepped first. With dimensions of 60x50cm, it was designed shroud rigging system.

Before the Duralumin mast was stepped both wooden masts were tested. The bare weight of the heavy mast was 100lb under its 5,000lb design weight; the bare wood mast weight was 150lb over its 4,600lb target, so a 400lb difference ended up only 150lb. But Duralumin fittings on the light mast weighed 300lb less than the Monel and bronze fittings of the heavy mast so there was a total saving of 450lb on the lighter wooden mast.

When the Duralumin mast was delivered and stepped in early June its substantially smaller diameter was a big difference in looks and windage. But, as might be expected, it was a bit squirrelly, ultimately requiring a change to a much larger second spreader. The diamond configuration was also eliminated.

Another innovation was a lower spreader that could be folded upward on the leeward side to provide space for overlapping jibs. Before tacking, to prevent loss of the mast, the leeward-side spreader was pulled straight by lines tended by a crewmember specifically assigned to the job.

As could have been predicted, there were some close shaves, making things exciting. Once, in an unplanned-for tack, the spreader man was not at his post. In another incident on approaching the Fort Adams shore while tacking out of Newport, the tending line jammed. In both cases last-second action saved the day. But the excitement was a bit much for Vanderbilt and he had abandoned the system by mid-summer.

(In a bit of interesting America’s Cup trivia, Alan Payne designed folding upper spreaders on Gretel II in 1970 for the same reasons of genoa leech clearance. They were slightly less risky as shroud tension ‘automatically’ pulled them straight during a tack.)

Trulok fittings

Another Burgess innovation that year was the invention of the ‘Trulok’ or swaged connection for wire cable.

Burgess knew that 19-strand cables were stronger and stiffer but could not be spliced onto fittings as conventional cable could. Working with the American Cable Company he created what we know today as swaged fittings. His were soft steel sleeves that were pressed onto the stay, workhardening in the process. The sleeves were then threaded to attach to eye or turnbuckle bodies. The new Truloks developed 100 per cent of the cable strength where splices could only achieve 85 per cent of a cable’s strength. The ability to use 19- strand cables produced a 33 per cent saving in standing rigging weight.

The combination of the Duralumin mast and the 19-strand cables left Enterprise’s weight aloft far lower than her competitors’, a significant factor – perhaps the most significant – in her victories in the Defence trials and Cup Match.

Park Avenue boom

As mentioned, by 1930 the aerodynamics of sails was an ever-higher priority. Because of his aviation background and his intimate knowledge of the work of fluid gurus Prandtl, Munk and Von Karman, Starling Burgess knew that optimising sail shape was key to keeping a performance edge.

He had never liked the fact that a trackmounted mainsail foot* created a large, flat area in the lower part of the sail, rendering it relatively ineffective drive-wise. To maintain the sail’s aerodynamic shape right down to the boom he designed a flattopped triangular-shaped boom with multiple flush-mounted cross tracks at 45cm spacing enabling the foot of the sail to ‘tack’ from side to side, maintaining the aerodynamic shape over its entire height.

The cross tracks had removable pegs that limited athwartships movement of the slides and had three settings, each set defined by green, yellow and red lines, similar to, as Vanderbilt described, the New York subway map.

According to Burgess, they even named each set Seventh Ave, Times Square Shuttle and Lexington Ave. In another reference to Manhattan, the fact that two men can walk along the boom side by side inspired the name Park Avenue Boom, a name that has survived to this day. Burgess also recognised early on that the boom’s more exaggerated endplate offered a worthwhile aerodynamic advantage over a conventional boom.

Typical of many America’s Cup developments over the years, the new boom was built in secret at Herreshoff Manufacturing Co in a shop closed off to visitors and only introduced late in the campaign. It was installed on 10 August. When it appeared it was a surprise to competitors left with little time to react.

The Enterprise team had always wanted to test how effective the slider system was. They got their opportunity in an impromptu tuning trial against fellow defence candidate Yankee, setting one side to the optimum curve and the other fixed at centreline. The test was successful: Enterprise proved faster with the foot curved using the cross track system.

This was an ‘advance’ over the deep depth ‘plank on edge’ booms that bent sideways to achieve the same foot curve, with struts and stays controlling deflections. In both cases the booms were built in wood using aircraft methods of the time.

The Park Avenue had the advantage of more endplate effect but was heavier; the early deep-depth booms were lighter but were less durable and broke from time to time. Ironically in 1934, while the Americans were impressed with Shamrock’s 1930 deep-depth boom and copied it, the Brits copied Enterprise’s Park Avenue boom. Vanderbilt claimed he could not see a performance difference between the two but simply ‘preferred the former’. In 1937 both Ranger and Endeavour II had developments of the lighter stayed booms, with Duralumin now replacing wood.

Burgess also sold Vanderbilt on fitting a smaller rudder to Enterprise that month. Apparently, though possibly faster, it took much more steering input and Vanderbilt never really got used to it, remarking in his book that in the future he’d strongly advise against major changes late in a campaign – something repeatedly borne out in America’s Cup history.

*Loose-footed mainsails, today so prevalent, were deemed impractical at the time due to the inferior strength and resistance to stretch of cotton sails.

Tacking luff mast (not used)

One idea that was seriously considered complete with a full detailed design and working model was a mast system like the boom’s enabling the mainsail also to ‘tack’, allowing the sail to get closer to the leeward side of the mast, eliminating much of the turbulence of the mast on the low pressure or lifting side of the sail that drives every sailboat. It required two tracks and heavier athwartships sliders, significantly adding to weight aloft. Also, Vanderbilt and Burgess worried it might be deemed illegal in a protest. For both reasons, it was never tried.

1934

In 1934 rules were changed introducing a minimum mast weight of 5,500lb, on average 500lb heavier than wooden masts to date. Not only was this a response to Enterprise’s overwhelming rig weight advantage but also to account for the evolution from triple-head rigs to doublehead rigs that induced higher shroud loads. Double-head rigs prompted three developments: - Quadrilateral jibs - Three-spreader rigs - Bar rigging

The significant sail development of 1934 was the quadrilateral jib. Vanderbilt noted that Francis Herreshoff had suggested a quadrilateral jib to him years earlier, sketching it on an M boat sailplan. Typical of what we all do sometimes, Vanderbilt failed to see the advantage and never ordered one.

Then in 1934 TOM Sopwith, Endeavour’s owner, never having seen or heard of Herreshoff’s idea, thought of exactly the same thing, believed in it and developed it. It wasn’t long before word got back to the US and copies appeared on the American Js. Had Sopwith kept it quieter a bit longer he may well have won in 1934, instead of losing a very close match.

(Personally, I think it a shame that such sails are outlawed on the current Js. What fun it would be to see and sail with quads on today’s vastly better-equipped boats.) The three-spreader rig with its narrowed staying base substantially increased shroud loads. Further adding to mast compression loads were now much larger houndsmounted runners.

The higher minimum spar weight was welcome. But cable shroud sizes required for the three-spreader rigs exceeded the capability of manufacturers, so single-piece shrouds could not be made. Burgess suggested having two or three parallel cables serving as side shrouds. As previously mentioned, Vanderbilt obsessed about windage. When the three-shroud solution was suggested, he balked at the extra drag.*

Starling Burgess responded by developing ‘bar rigging’ or what we now call rod rigging. But there was a catch: although sizes could now easily be reached, no bar longer than 17ft could be heat treated in the vertical ovens of the day. The solution: connect the bars in the middle with a threaded turnbuckle-like connector with lock nuts at each end to be tightened to prevent rotation once the rig was tuned.

Worried about fatigue cracking in the highly heat-treated bars, steel experts forbade drilling holes in the rod ends for cotter pins – later we’ll look at how 24-year-old Rod Stephens learned perhaps the hardest lesson of his career with such fittings as rig boss on Ranger. US boats Rainbow and Weetamoe, and ultimately Endeavour, were all fitted with such shrouds in 1934.

Starling Burgess-designed pear-shaped aluminium masts were made for both Rainbow and Weetamoe.

Interestingly, in 1936 Vanderbilt forsook his aluminium mast for a Frank C Paine-designed ‘round and slender’ steel mast that he judged had less windage than the aluminium one which set up ‘too many eddies on the lee side of the mainsail’.

* Ironically, for its 2003-generation IACC yachts Luna Rossa determined that two smaller shrouds placed unconnected one behind the other had lower windage than a single larger stay and would therefore be faster. The ghost of Vanderbilt may well have remarked to himself, ‘Hmmm’.

1937

When the NYYC received a challenge in the summer of 1936 most agreed that, after 1934’s hair’s breath defence, sticking with the existing US fleet was too risky and a new yacht was commissioned, but not without serious funding problems. Other than Vanderbilt, no one at the New York YC offered to contribute. Vanderbilt seemed ready to go it alone when Starling Burgess talked the owner of builder Bath Iron Works into building a new yacht at cost.

The boat was of course Ranger. Although in Vanderbilt’s own words Ranger was ‘The Super J Boat’, it was in fact a careful refinement of everything learnt up until that time.

Her mast, an evolution of the early Duralumin masts, has always been a favourite of mine. It was very clean, made this time with flush rivets. Spreader and other fitting details are worthy of close inspection even by modern aircraft standards. I always enjoy viewing her masthead crane, with its elegant halyard lock, which was displayed for many years at Newport’s Museum of Yachting and is now in the possession of Elizabeth Meyer, whose efforts to restore Endeavour brought about the modern rebirth of the J-Class.

Perhaps more effective were Ranger’s very fair flush riveted topsides, avoiding the distortion of welded plates. Apparently Rod Stephens, visiting every Saturday, drove the builders crazy taking myriad measurements and insisting on reworks to ensure the welded frames’ accuracy.

Ranger didn’t have fairing compound so the fairness evident in all the photos of her was impressive. Vanderbilt remarked that due to her fairness she behaved identically on either tack – though it must be noted that the previous Herreshoff Js were built with riveted bronze topsides and were quite fair in their own right. Ranger was also the first J with all spars – mast, boom and spinnaker poles – in aluminium.

Ranger was launched in Maine and it was decided to step the mast at the yard, then tow the boat around Cape Cod to Newport. The bridges in the shorter trip option through the Cape Cod Canal were not high enough to allow Ranger to pass through with her mast stepped. They could have chosen to tow to Newport with the mast stored on deck, but did not.

It is a long, harrowing story but during the first night of the tow, in relatively calm seas with mild side swell, things went badly wrong. Just after nightfall, with Ranger rolling gently side to side, her crew began to hear noises aloft that began with ‘tinkling’ sounds. The noise became louder with each passing hour. Soon it was obvious the rig was slowly going loose.

During the night the rigging seemed either to have broken or come apart above the first spreader on the port side (not only was it dark but also very foggy so no one knew for sure, and sending a man aloft was out of the question). In addition to the darkness and fog, a slowly building SE breeze aggravated the situation.

Before dawn it was decided to head to nearby Marblehead in the hope of saving the mast that was now bending almost 90° to starboard with each roll. Just after daybreak the mast, now whipping in deep bends side to side, finally broke and, after the crew cut or unbolted it away in quick fashion, sank into the deep Atlantic.

Although Rod Stephens very completely and professionally described the event from his vantage point on the towing vessel, one can only imagine his real thoughts and emotions as rig boss. In All This and Sailing Too Rod’s brother Olin described a call that morning from a ‘very unhappy’ Rod. According to Stephens, when he called Vanderbilt with the bad news, the boss listened quietly then ended the discussion with, ‘Well, now we can go through the canal.’ Rod never knew whether or not comic relief was intended.

At the same age as Rod was in the summer of 1937, I was given the same responsibilities for a 12 Metre mast during the 1970 Cup summer. I had huge worries all summer about things not faintly resembling what Rod went through, so every time I think about the story I can viscerally imagine the true devastation Rod must have felt.

(I am convinced that had that mast been, say, the modern J-Class Lionheart’s seamless carbon spar it would not have broken. It’s both lighter and carbon is significantly better in bending. When we first began delivering carbon masts, more than a few customers came back after tough races, saying things like, ‘If we still had an aluminium mast we would have worn it.’)

The problem turned out to be the lock nuts: as the barrels loaded up they strained (elongated) ever so slightly but still enough to render the nuts loose even though welltightened under no load. So, as Ranger rolled back and forth, the rigging loaded and unloaded and each time the nuts backed off slightly. That all the fittings were very carefully cleaned and lubed before stepping probably increased the chances of the result (no good turn goes unpunished, right?).

With the nuts backed off just a bit, the barrels were free to unwind until they came off. Ranger’s rigging was, in Rod Stephens’ words, ‘hand me down’ bar rigging from Rainbow’s 1934 campaign. Well, why didn’t the rigging do the same on Rainbow? All I can think of is that Ranger ‘tacked’ that night almost as much as Rainbow did all summer in 1934. And surely regular rig checks found the occasional slightly loose lock nut that was just retightened – no drama.

Vanderbilt hinted directly to Stephens that originally someone didn’t tighten the port rigging enough. Rod disagreed and later in the season tightened the V1 with big wrenches to Vanderbilt’s satisfaction; sailing later that day in moderate breeze he climbed to the mid-stay barrel and showed Vanderbilt it was loose, satisfying the boss.

I remember years later an encounter with Rod at a mast shop I was running in Germany in the 1970s. His expression became unpleasant when he saw turnbuckles with lock nuts on one of our rigs in the shop. He explained that high shroud loads can cause such lock nuts to go loose. Then added bluntly that if I ever delivered an S&S rig with such turnbuckles it would be my last.

I hadn’t yet known the Ranger mast story so I was a bit taken aback as Rod was a friend of the family. Dutifully, I never used such turnbuckles again. When I learned later the story of Ranger’s tow, I finally understood.

With the conclusion of the 1937 Cup and the approach of World War II, the J Boat era ended. Super J Ranger was scrapped in the middle of the war in 1942. The other US boats were similarly scrapped for the war effort. At the end of the war no one had the slightest thought of ever again building a J, now a prohibitively expensive endeavour. The America’s Cup went into hibernation.