Building the cutting edge sailing yacht Athos

The stats are impressive enough. Measuring 62m overall, Athos has a beam of 10.9m and weighs 390 tonnes at half load. Her 1,980 square metre upwind sail area requires the largest carbon rig ever made by Rondal, with a 54m foremast and 61m main.

Holland Jachtbouw (HJB) is building Athos fully to MCA and Bureau Veritas rules, and she is the largest sail yacht ever built in aluminium alloy 5383.

The early decision to use this strong, high modulus material was the first of many premiers for a hugely ambitious project that revolves equally as much around technical sophistication as her imposing size.

‘This project has been a process of continuous development driven by the owner,’ says Zijlmans, production director at HJB. ‘He adores engineering and constantly endeavours to push the needle of efficiency. The owner is not afraid to take risks and while confident that we can pull it off he is also taking his own share of the responsibility, right down to warranty issues.’

Many of the requests have involved installations and systems that were simply unavailable on the market and therefore had to be specially developed. It is clear that the flexibility offered by the World Class Manufacturing principles which HJB follows has proven indispensable for coping with these new developments.

Designer Andre Hoek was on the front line of this evolutionary process from the outset, and worked on the owner’s previous sailing yacht.

‘In 2005 I took him to see the 55m ketch Adèle and he loved the twin deckhouse owner’s privacy concept that Hoek Design pioneered on this yacht. Initially, he felt that Adèle was a little too large for his requirements, which seems ironic now when you consider how the project grew from 44m to 58m by the time HJB joined the team in 2006. As we developed Athos, more space was added for the crew, guests and equipment.’

Within weeks of HJB winning the tender, the owner had added a further four metres to Athos in order to cater for a new positioning for the boom vangs and increase the size of the engine room. He also began to devise the most powerful hydraulic system ever installed in a sail yacht to date; a monumental feat of engineering that would eventually require over 30km of wiring and a great deal of smart thinking.

‘The initial brief for a 90kW bowthruster was superseded by a request for a more powerful bowthruster,’ remembers Zijlmans. ‘The amount of power [150kW] was unprecedented and when it became clear that he would have to finance some serious development work, the owner decided to commission a sternthruster at the same time with the same power.

‘Moreover, both thrusters had to be able to be operated simultaneously with both main engines running on a fixed rpm of just 1,500 because he also wanted to have the option to run the complete installation in combination with gearbox-driven generators. This was quite a puzzle to work out and required well over 2,000 engineering hours.’

With 300kW on the thrusters alone, and taking into account efficiency losses and the hydraulically powered controllable pitch propellers, Athos now had a simultaneous hydraulic power factor in the range of 450kW.

‘By this time, we had prepared a hull construction and layout for a system one fifth of the size so we had to rethink the proposed design, working everything around the entire installation to keep it all concealed,’ says Zijlmans. ‘The pumps on the main engines and generators are huge and the piping needed to transfer and hold the pressure involved in such a vast system power is tremendous.’

Some 80mm in circumference, the pipes and their brackets had to be installed in a way that would be both resilient and sound insulating. While such heavy duty gear may be common in the commercial shipping sector, the restrictions on a luxury yacht where real estate is so precious – and peace and quiet so valued – made this a colossal challenge.

A similar dichotomy between two different maritime worlds can be seen in another of the owner’s innovations, which had been a key feature of the original specification.

Athos has double redundancy of almost every system on the boat, divided into port and starboard systems. Twin main engines drive two propellers, while two 90kW diesel gensets and two shaft generators provide a parallel power supply (add in the emergency generator aft and you have five gensets on a sail yacht). The shaft generators are another relatively common feature in the shipping world that you will not find on many superyachts.

The owner’s requirement for Athos to have dynamic positioning (DP) is also very unusual.

‘As far as we know, this is a first on a sail yacht so we had no reference point,’ says Zijlmans. ‘It is not the DP system itself that is complex, it’s the communication of the signals within the system and how parts of the yacht respond that are the big deal. The installation itself is driven by GPS signals, but the desire to have it hydraulically operated was something altogether new.

‘Finding a solution entailed a great deal of discussion with the yard, the DP installation manufacturer, the hydraulic components and engine controls suppliers, and the naval architects. In addition to being able to enjoy quiet without anchoring up, a secondary benefit is that it will be possible to manoeuvre Athos using a “simple” joystick.’

Athos also features a fully integrated stern anchor. Again, it is not the anchor itself that is revolutionary but the way it is being operated – in this case remotely, with a uniquely devised system that retracts, rotates and pivots the anchor into the hull.

‘The logistics of implementing this pushbutton-controlled installation within the framework and layout of the stern were phenomenal,’ adds Zijlmans.

The arrangement of the main anchors is unique. Normally these are integrated into an aluminium hull and then the area around the anchor opening is clad in stainless steel plates.

Another fascinating feature incorporated into Athos’ giant hull is her hydraulically operated centreboard, which is seriously complex both from a structural point of view and technically.

From the earliest stage, the yacht’s single rudder and keel centreboard configuration was designed to minimise the wetted surface and enhance performance.

The huge 6m centreboard construction itself was designed in order to offer an unparalleled degree of safety. The bottom two metres are fitted on to the top part with a snap-bolt construction and the board has an indirect connection to the hydrocylinder. Should the board hit something, the mechanism will take the breaking load by deforming or breaking and the cylinder will not be affected.

Walking around the giant hull in a construction hall it is easy to forget that structures of a similar standard of sophistication and an even greater magnitude will soon be sprouting out of the deck.

Rondal has been responsible for building the giant masts, which are made of high modulus carbon fibre in order to minimise weight. Further significant weight savings have been realised by replacing the heavy stainless steel cylinder boomvangs normally found on a yacht of this size with two carbon vangs tailor-made by Navtec. Weight issues were also a key reason to use PBO standing rigging instead of rods. This was created by Smart Rigging, which had to engineer and manufacture the longest cables thus far made for a pleasure vessel.

The records keep on tumbling as we explore Athos’ spars. Being a Panamax boat she has a very tall sail plan for a schooner. At 61m, the main mast is the longest mast built by Rondal or anyone else in The Netherlands. The 15m fore boom and 23.5m main boom are made of a high strength carbon fibre sandwich construction. Each has an electric sun awning system on both sides and over the full boom length, custom designed by Rondal. Meanwhile, the main boom is the longest built by the company so far, even larger than the boom for Athena.

In terms of its operation, Athos has an entirely pushbutton-operated rig that includes in-boom furling sails, hydraulic boom vangs and captive winches for the sheets and halyards.

‘When we first designed Athos, she was intended to be an ocean-going cruising yacht,’ recalls Hoek. ‘But after the owner started enjoying racing he decided to increase the emphasis on performance.

‘This entailed changing the sail plan and we opted for a new development in the form of furling booms with roached main and foresails. The furling booms are for ease of operation, while the roached main sails enhance performance.’

Here too we have another illustration of how many people had to work closely together to research the solution, including the owner, designers, sailmakers and equipment suppliers.

Eventually, a fully battened sail was developed that furls into a boom with a large roach. To handle the huge batten loads involved, Schaefer Marine designed a special hinged track system on the back of the mast. The entire track rotates and has an outer groove for the batton receptacle and inner groove for the bulk load.

After some fine tuning on the owner’s current yacht the system works well, and now these experiences are set to be translated on to a much bigger scale.

Athos is designed with captive winches so that she can be sailed pushbutton. Because of the yacht’s massive hydraulic capacity, all the winches and other sailing related equipment can be used simultaneously.

‘The most incredible shapes of blocks and stainless steel brackets were required in order to get everything organised,’ says Zijlmans. ‘A load sensor system has also been developed to measure tension in critical lines, with monitors installed and the signals from the rails collated and displayed on screens in the engine room, deckhouse and crew areas.’

Once completed there will be many more high-tech features to be admired on Athos from the moment one steps aboard, which can be from either side of the yacht via boarding ladders that retract into the platforms or using a bespoke stern platform. In the cooling arena alone, Athos has many customised innovations, each of which sound relatively simple but required a separate study in their own right.

Her on-deck dashboards, for example, are not linked into the overall air-conditioning as normal but cooled locally by ventilators and cooling elements that have been shaped to fit within the exact space and equipment.

A similarly compact and lightweight solution was also developed for the audio-visual stacking area. And the engine room has a very special system that lowers the temperature using outside cooling water and blowers.

Perhaps the greatest testimony to the achievement is that all the systems and solutions detailed here have been completed without impinging on the interior volume of the yacht’s living areas.

A great deal of space has been dedicated to crew as the owner recognises the need to attract the very best people to run such an ultra-advanced vessel. One example is the spacious and comfortable engineer’s accommodation connected to the main switchboard control room.

An amazing amount of storage has also been found for toys, one of which is a Polaris flying tender (a lightweight Zodiac with a hard bottom and wings) that will be garaged in the forepeak. Two other custom tenders will be kept on deck, while there is also storage for two Optimists, two Laser Vago sailing dinghies, and all kinds of other toys in two huge side lockers next to the deckhouses.

Athos is a classic case of how tomorrow’s technology can be integrated in a yacht that visually speaking pays homage to the golden days of yachting past. The vast teak deck may still be partially covered for protection but it is already clear that she is going to look spectacular.

Come Athos’s launch in spring 2010, however, and aesthetics will not be the primary concern of Captain Nick Haley. No stranger to record-breaking yachts, having spent six years at the helm of Windrose of Amsterdam (also built by HJB), Haley is not underestimating what will be involved in ensuring that the extraordinary technical systems above and below Athos’ waterline actually work in practice.

‘Although Athos’ critical systems have undergone a detailed development process, we still foresee an extensive commissioning and sea trialling period,’ he says. ‘There will no doubt be some prototype systems that do not work perfectly first time, and possibly some systems that we assume will not give problems end up doing so. Hopefully there will also be systems that we think might give commissioning headaches and yet work trouble-free straight away.’

Haley also believes that the biggest challenge of all will be to extract the full sailing performance from the boat.

‘This process will continue well after the yacht leaves HJB. As the dimensions of and potential loads in the rig are so great it will be an awesome and exciting task.

‘As well as the new track system to handle the roached in-boom furling sails, we are also at the limit of what is possible with running rigging, hardware and winches. In more than one sense we will be setting off on a voyage of discovery.’