The clipper rig as we know it may be a thing of the past.
The clipper rig as we know it may be a thing of the past but an updated version will soon be launched and is destined to add a new dimension to superyachting. David Glenn reports
It seems appropriate that someone who has spent his life in the risk business should be attempting one of the most daring developments in yachting. Later this year, Tom Perkins’s three-masted 289ft clipper yacht Maltese Falcon will be launched from Perini Navi’s Yildiz yard near Istanbul, where all eyes will be on her extraordinary square-sailed Dynarig which promises to add a new dimension to superyachting.
For a man whose venture capital activities have started companies like Google, AOL, Amazon.com, Genentech and Sun Microsystems and who earlier in his Silicon Valley career managed Hewlett Packard, building a big yacht might seem like a walk in the park. But this is no ordinary yacht. And her rig is genuinely revolutionary, potentially a serious alternative for sailing yachts
over 200ft (60m).
In an unusually detailed paper delivered recently at Project 2004 in Amsterdam, Perkins and his team – including Gerry Dijkstra (naval architecture), Ken Freivokh (interior and exterior styling), Damon Roberts (rig design and builder) and Franco Torre (from the builders Perini) – described how some of the unique design challenges have been met. For two hours the assembled cognoscenti from the superyacht industry sat there goggle-eyed.
Tom Perkins, an inventor himself in the field of laser technology, admitted that both he and his friend Fabio Perini, with whom he has built two previous yachts, were “both nerds who get off on doing new technical things”. By the end of the session that seemed like an understatement.
Three biggest yachts
But this wasn’t just about Maltese Falcon. From the outset Perkins put the yacht in context with the two other existing superyachts that have knocked our socks off in recent months – namely Joe Vittoria’s VT-built Mirabella V (the biggest sloop in the world with an LOA of 246ft 8in/75.22m) and Dr Jim Clark’s Huisman-built three-masted schooner Athena (the biggest privately owned sailing yacht in the world with an LOA, including spars, of 295ft 3in/90m). Falcon’s ‘biggest’ claim is for being the largest modern clipper. About the only other thing they have in common is that they are all owned by Americans.
But being very much a scientist in his own right and with a competitive streak which has been a distinguishing feature in his yachting exploits (he drove his Herreshoff schooner Mariette very hard indeed on the race course), Perkins was quick to point out that ‘the Falcon’ is not only the longest on deck at 278ft 10in (85m) but more significantly is much longer on the waterline at 256ft 6in (78.2m). Both Mirabella and Athena measure 200ft, just over 60m, in that department.
Despite his expertise at managing the risk versus dollar spend equation, even Tom Perkins admitted with the wryest of smiles: “As the dollar has progressively collapsed against the euro and the pound, the size of the yacht has increased – if anyone can explain this miracle I would appreciate it.” Among the uneasy shuffling in the audience one could almost hear the mutterings of: “Who, me?”
He clearly also has a vision of all three yachts going head to head in a big, open-water, long-distance contest, perhaps following a clipper route. So, continuing the comparative theme, he made some predictions about performance based on hard data, specifically for sail area:displacement and length:displacement ratios (see table above).
“If there was a race in light air I think Mirabella would be a killer because of her favourable sail area:displacement ratio, but in more breeze the advantage would move towards Maltese Falcon because her length:displacement ratio of 7.28 will have more meaning.”
Why an old steel hull?
It seems odd that for all the innovation and dollars being pumped into the Falcon’s rig, her hull is based on an old steel shell which had been lying alongside a dock at Perini’s Turkish base. In fact, it was a project which had been derailed. The original naval architecture is in-house Perini, and intended for cruising. Perkins said that he had been discussing the hull for some years but the question was, how could he turn it into a fast modern yacht?
Enter Gerald Dijkstra and Partners, the Amsterdam-based big yacht specialists who were able to assess the hull in conjunction with the Dynarig, a concept which they had been searching for an opportunity to develop. Interestingly, Gerry Dijkstra showed a slide of four different options for Tom Perkins, including a much more conventional schooner and a traditional square-rigger.
But there was never any doubt that the technical challenge the Dynarigged clipper yacht posed would make it the natural choice and when Dijkstra’s performance predictions came through there was real excitement about potential.
Perkins and Dijkstra favoured steel because Maltese Falcon is going to be in her element in big seas and big winds. Incredibly, Dijkstra and Damon Roberts from Insensys, who is responsible for designing and building the three free-standing, rotating carbon spars and 18 yards, claim that Falcon will be able to carry full sail in 55 knots of true wind which could equate to 70 knots apparent.
“We’re going to sail her,” said Tom Perkins, “and we are hoping for high speeds in the ocean – so rigidity and the strength of steel are important.” The suggestion is for long, sustained average speeds in the high teens. The other big consideration was the need to resist the immense athwartships forces associated with the free-standing concept. The numbers for steel stood up well.
On the weight budget
Mast supportBut the hull was modified dramatically following model towing tests at Delft University. It was originally conceived with a forefoot bulb but the results suggested this should be removed. The shell was lengthened and the rudder moved aft. The depth of the hull was increased by 1.7m so that a further 100 tons of ballast could be accommodated. In total she carries 200 tons of lead ballast and 50 tons of water ballast, which can be transferred in 20 minutes.
The other very obvious appendage is a daggerboard, which Tom Perkins said will probably only be fitted when undertaking a record attempt or racing. It increases draught from 19ft 6in (6m) to 36ft (11m). Maltese Falcon’s displacement is predicted to be 1,240 metric tons, considerably more than that of Athena (1,068 tons) which is built in Alustar aluminium alloy. “We are on the weight budget so far,” said Tom Perkins who recognises the dangers of running out of control if sailing performance is the ultimate aim.
Despite Tom Perkins’s loyalty to the Perini marque and his acceptance that the yacht will carry the company logo, he has decided to break away from the company’s stock in trade dark blue livery. Perini’s keenness for conformity – including the Henry Ford-style mantra ‘you can have any colour so long as it’s blue’ – is a well-known cornerstone of their marketing policy . “Well, I am going to paint my new boat black – I don’t know whether Fabio has signed off on that yet, but that’s what I’m going to do.” Polite laughter…
Testing the Dynarig
Dynarig testingTom Perkins bought the residual technology for the Dynarig from the German government who researched the idea in the 1960s when they considered sail to be an alternative means of power when the oil crisis of the time looked like worsening.
Much of the hard technical number-crunching work had been done. What the Maltese Falcon team wanted to know was would it actually perform in practice, a stage the Germans never reached. So the team started with a one-sixth scale model with yards made in wood.
A fan was directed over the surface of the sail while the angle of attack was altered for optimum performance. First signs were good. Then they transferred the single-panel square sail to a small dinghy. This looked amusing but the result was just as impressive with the crew finding the rig extremely easy to handle and promisingly efficient.
Wind tunnel tests were then conducted at the University of Southampton where the team were able to observe air flow over a full suit of sails, establish lift and drag coefficients and the centre of effort for the sailplan.
A large radio-controlled model was built to see how well the yacht would go through a tack and once again there seemed to be few problems. Initially the foremast sails would be tacked first to carry the bow round but it is hoped that the full-size version will be able to rotate all her masts simultaneously when going through a tack and that the difficulties square-riggers encountered in such manoeuvres, such as being caught in irons, will be avoided.
The final part of the test was a full-size sail with yards and trusses set on a latticework mast set in concrete on the dock in Turkey. This was equipped with all the outhauls and furlers necessary and refinements were able to be made to guiders, tracks and the cross-panel sail itself. “We routinely tore it (the sail) to shreds,” said Perkins, “but that never happens now.”
The rig also had Damon Roberts’s embedded fibre optic strain monitoring sensors fitted so tests could be carried out on the full-scale carbon structure. “These showed us what happens when we bend and twist the rig – it shows how the rig is feeling, if you like.”
Another challenge involved the unusual relationship between the hull and the three free-standing, rotating rigs. A feature of unstayed masts is that instead of conventional vertical chainplate loads, the hull has to withstand athwartships loads and be designed accordingly.
Damon Roberts quoted the bending moment at the deck as 17,000,000 newton metres which is the equivalent of 31 London taxis hanging off the end of a 30m pole! Fifteen load cases were carried out, assuming 2G for hull impact and 1.5G for grounding plus tests for sagging and hogging to prove that she would survive being suspended between waves or perched on a crest in worst case conditions. The rigs were tested in a theoretical 122-knot wind and it was determined that she would heel to 30° in her natural 10 second rolling period.
When angled efficiently, the Doyle-made square sails suffer very low loading due to the yard support, so simple Dacron can be used to good effect. In 50 knots of wind no more than 900kg loading was measured, tiny compared with leech loads on some far smaller ‘conventional’ rigs.
Rotating the masts so that each set of five squares is at the optimum angle of attack will be crucial, particularly when trying to reach top speed close-hauled. But Gerry Dijkstra explained that the optimum apparent wind angle will be about 45°, which is what the Germans had determined 60 years ago.
Heel angle, especially hard on the wind, is going to be an interesting point. Almost in passing during Tom Perkins’s presentation, the sailing performance figures ended with a heel angle of 20° being quoted. That’s an alarming (and usually inefficient) angle in a small yacht but in Falcon with a beam of 41ft 4in (12.6m), the effect will be magnified.
Controlling it all
“This is a true revolution in sail control,” said Perini’s Franco Torre, representing the builders, who also have responsibility for sail handling and mast rotation.
It seems extraordinary that despite three masts, 15 sails and 18 yards, not a single piece of running rigging will be led on deck. Patrick O’Brian would be turning in his grave. Instead, as explained in the box above, the entire furling system will be aloft, with a total of 75 electric furling winches mounted in the rigging. “Simple, light and reliable” is how Franco Torre described the system but one must wonder whether this complexity can be relied upon for prolonged periods in heavy conditions which could, conceivably, involve icing.
All winches are operated from the ‘control station’ on deck equipped with an array of lights and dials, which although numerous, basically enable sails to be wound in or out. The station is also where the crucial angle of attack is set for sails by rotating the masts. It is important to understand that the yards, trusses (see above) and masts are a fixed entity and that the entire edifice rotates on a heel bearing. The heels of the carbon spars are glued into steel buckets, linked in turn to the rotating mechanisms which sit on universal ball joints. This should allow the masts to bend below deck without damaging the rotation gear. The masts and deck structure are supported wherever the spars pass through a deck bearing.
Turning and supporting the masts with enormous bending loads is a technical minefield but Fabio Perini and his engineers have devised a hydraulic turning system which can move the assemblies through 180° in just over a minute. There are some 60 cables running through each mast, some of them fibre optic for the rig load sensors and they have further complicated the rotating mechanism.
Tom Perkins said: “Unlike my friend Dr Clark (Athena’s owner), we never let the computer close the loop,” emphasising that, in extremis, the royals (uppermost sails) are designed to blow out and furling can theoretically be carried out by hand.
“In the old days the captain would come out with a shotgun and shoot out the royals if the crew couldn’t get them down in time,” said Perkins who pointed out that the storm sails are the lowest sails and not the biggest (see opening illustration).
Carbon loo roll holders
The expectation might be for Maltese Falcon to be fast but her interior will be a study in lightweight luxury. When Ken Freivokh was commissioned to style the vessel, he described it as a project “without compromise” and one of “high-tech simplicity”. “She has a relaxed, open, minimal style with a totally open plan main deck and only three guest cabins,” said Freivokh. Everything from a ceramic model vintage sports car emerging from the centre of a table at the press of a button, to velum, maple and aluminium tiled walls, leather floors and carbon fibre loo roll holders can be found in the specification.
Unlike Mariette’s Edwardian original interior, and Atlantide’s art deco style (Tom Perkins’s motor yacht for which Freivokh was responsible), Falcon’s interior has a clean simplicity about it with a dramatic, multi-deck atrium built around one of the masts. “We are using glass floors which allow you to see the mast sleeve and cantilevered steps,” said Freivokh who also styled the deck level ‘spider’ supports which help support the free-standing spars. The clean, modern lines continue to run through the saloon, writing room, library, gymnasium and a separate passage cabin on the bridgedeck which has its own terrace.
Use of lightweight honeycomb coring, carbon fibre trays and aluminium fittings is extensive to keep to the weight schedule. Camera shutter technology is being used for some skylights and low power LED lighting is being used throughout the yacht. Key elements of the exterior styling include the louvred superstructure, the large light and signal mast up forward and the enormous ensign staff.
Whether you look on deck, below or at Maltese Falcon’s startling three-masted rig, this yacht must be regarded as truly revolutionary and is likely to draw even more comment than Mirabella V and Athena. Some say she is too complex and her rig unwieldy but whatever the outcome she will be the subject of intense speculation until she launches later this year.
This is a truly monumental project both physically and technically, but Tom Perkins, right at the end of his presentation, attempted to put it in perspective. “I’ve worked out that it will have taken three to four million man hours to complete this (yacht), which includes building engines and things like air conditioning plants – but that’s just five per cent of the work it took to complete the great pyramid of King Cheops near Cairo, which took 32,000 men 23 years to complete!”
What is a Dynarig?
Radio-controlled modelEach free-standing mast carries six yards each designed with a 12° arc, a critical element of the design to ensure optimal airflow over the sails. Each mast carries five sails, starting from the top with the royals, the topgallants, the upper tops, the lower tops and finally the courses.
The sails stow on vertical furlers inside the masts and are then hauled out to the ends of the yards. The head and foot of each sail are set in internal tracks in the yard so that each mast carries, in effect, a continuous five-panel surface.
Each sail is unfurled using a set of four winches which pull the ‘corners’ of the sail to the ends of the yards. A single motor operates the vertical furler to douse the sail so each sail has a total of five motors, 75 in all in the rig.
The three 60m carbon fibre masts are being moulded in purpose-built workshops at Perini’s yard. A single mould is being used to build up the 174 layers of T800 intermediate modulus carbon used in the matrix, which is highly complex because the spars not only change from being elliptical to round but also taper.
In addition, there’s a slot running along the forward face of the mast to accept the sails. “There’s an H beam running through it to deal with the open slot and the loss of strength,” said Roberts. In spite of this, the top of the mast is able to bend through an arc of 11ft 6in (3.5m)!
Attached to each of the masts are six moulded trusses or mountings which form the solid connection between mast and yard. The trusses also form the platform on which the furling winches are mounted.