Worlds Largest Superyacht Boat international Magazine

The Environmental Superyacht

The first in a planned series of RSD Eco-yachts, the 70-metre shown here incorporates as standard a series of environmental systems designed to minimise both its consumption of resources and waste outputs.  These include:

  • 100 square metres of flexible solar panels producing 20kW@ 22% efficiency.
  • Vertical axis wind generator producing over 7kW of power.  The system used on the RSD 70m incorporates a mechanism that folds in the helical wings when winds gust over 40 knots.
  • Heat convection as twin solar-heated towers draw air through underwater pipes into vessel, reducing reliance on air conditioning.
  • Waterline length is near that of length overall, offering a good length/beam ratio that improves hull efficiency without reducing interior volume.
  • Electric azimuth drives with CPPs driven by sequentially activated diesel generators. Capacitor storage-system for ‘regenerative braking’ also incorporated.
  • Diesel fuel storage and delivery system is up-rated for biodiesel, which can be mixed with conventional diesel to improve efficiency.
  • Foredeck mounting point and winch for Skysail, to be used on longer distance passages.

Boat International November 2008

  1. Introduction
  2. Propulsion and power
  3. Energy conservation
  4. Waste management
  5. Leaving behind nothing but a (minimal) wake
  6. Conclusion

1. Introduction

These days you would have to be marooned on the proverbial desert island to escape today’s favourite eco-buzzwords: sustainability, environmentalism, carbon-neutral, zero impact, the list goes on, and you can hardly open a magazine or newspaper nowadays without coming across them within the first page or two.

The world of luxury yachting is one that so far has not figured high on the lists of groups or activities that pose a major threat to the environment, or contribute to man’s impact on the climate.  This is in part due to the fact that in the grand scheme of things there just aren’t that many superyachts in the world compared to, say, luxury cars or private jets, and the vast majority of environmental activists go through their lives without laying their eyes on one.  But that’s not to say that superyacht owners and builders can afford to ignore the prevailing winds in this contentious area, and it is to the industry’s credit that so much discussion is already taking place.

Outside influences have played their part of course, with new laws, particularly in the EU, on the disposal and recycling of waste affecting every part of the production and manufacturing process for yachts and their components.  The ban on TBT antifouling paints in 2003 due to their harmful effect on marine organisms is another such example.  The fact remains, however, that superyachts represent some of the largest monuments to conspicuous consumption in the modern world today, and the amounts of carbon given off when a hundred tonnes or more of metal, glass and tropical hardwood are moved around at twenty plus knots through water – a liquid around 800 times denser than air – are truly prodigious, particularly when seen on a per capita basis relative to the number of people generally on board.  We cannot expect to remain out of the spotlight for much longer.

There is good news, though, for the many owners who wish to combine the enjoyment of their yachts with their desire to minimise their impact on the places that they choose to visit, with technology and science coming to the aid of yacht designers such as Rainsford Saunders Design in London, giving them the tools to create superyachts whose consumption of resources and residual impacts will be a fraction of those generated by their forebears.

RSD has recently introduced an ‘ECO-yacht’ range, a move that is intended to clearly differentiate these designs from the many yachts that are launched today incorporating elements of environmental technology yet fail to embrace whole-heartedly the ethos of making minimum consumption and minimum waste output the starting point of the project.

"We are deliberately taking the commitment to sustainability in yacht operations on to new ground" said RSD director Rupert Mann.

“The Eco-yacht principle is all about integrating environmental coexistence into the design of a yacht from the moment the first line is drawn.  As designers the responsibility for everything that goes into, and comes out of, our yachts ultimately lies with us, and that means that if we are to take that responsibility seriously we have to design the yacht around the necessary systems, and not the other way round.  We aim for the Eco-yacht marque to represent a benchmark for standards in this field.”


2.  Propulsion and power

The most obvious goal for the owners of large yachts is the reduction of the amounts of fuel that they burn.  The fact that the price of oil has multiplied by more than five in less than ten years is unlikely to cause too many sleepless nights for those able to afford such craft, but efficiency gains will not only reduce their carbon emissions but for some more importantly increase their range, giving added trans-ocean capability and opening up new cruising grounds.  These gains are coming from both improvements in engine design and, more dramatically, the use of lightweight composite materials in the construction of superyachts that give the same or greater strength and rigidity as conventional materials but weigh substantially less.  The recently-launched 37m Ermis2 uses high elongation Airex R63 linear foam cores coupled with carbon fibre and Kevlar®-reinforced epoxy skins to make the shell and structure not only substantially lighter than even an equivalent solid carbon fibre laminate, but also substantially tougher.  The total composite package for hull, deck, superstructure and internal structure came in at just 17-tonnes, showing what can be achieved with modern materials.

For those who wish to go the extra step, RSD considered the options available to owners looking to reduce or eliminate the use of hydrocarbon fuels altogether.  Solar power and the use of photovoltaic cells is one energy source that becomes more realistic the larger a boat becomes.  In their current study for a 140-metre design the Rainsford Saunders team envisages having 60 m2 of solar panels mounted on the superstructure which would be capable of producing enough stored charge to run the entire vessel’s lighting systems; even enough to manoeuvre the ship at low speed around a harbour using the planned rotating Azipods, thus reducing the dependence on conventional generators for electrical power.  In fact, the development of CIGS (copper indium gallium selenide) solar cells by companies such as Nanosolar in the US opens up the potential for much greater use of solar energy.  Solar cells using this technology can be printed onto flexible surfaces using a semiconductor ink, allowing them to be deployed on almost any surface, and without adding much weight to the superstructure.  Other manufacturers are working on transparent solar panels that could one day replace conventional windows, although efficiency levels are currently low.

The future of clean, on-board electricity in meaningful amounts lies, however, in the development of portable fuel cells.  UK-based Voller Energy is at the forefront of developing fuel cells that can make a practical contribution to the energy requirements of large yachts.  Previously the problem with fuel cells was the issue of obtaining and storing the highly volatile hydrogen that they use as fuel.  Voller Energy has come up with a process that uses LPG as the primary fuel, with the fuel cell extracting the hydrogen that it requires and releasing small amounts of CO2 as a by-product.  Voller’s current Emerald fuel cell produces just 1kW of power, but for superyachts the company is marketing them as a power source that can be either fitted in multiple installations to provide continuous charging to the main batteries, or installed singly about the yacht to provide the same function for critical pieces of equipment that need an uninterruptable power supply.  For owners that value their peace and quiet, particularly at night, the great advantage of fuel cell technology is that it is extremely quiet and free of vibration.  More powerful units are in the pipeline.

As for running the engines, renewable biofuels are currently receiving a good deal of publicity.  The idea of growing crops to produce vegetable oils that can then be converted into biofuels is not without controversy, but the technology is rapidly growing in popularity, aided by developments such as the recent success of the 24-metre tri-hull wavepiercer Earthrace in setting a new powered circumnavigation record, using two 1080hp Cummins Mercruiser engines powered 100% by biodiesel to travel at speeds of up to 25 knots.  Many conventional diesel engines can already run on biodiesel, or on a mix of bio and conventional, but for both owners and the bunkering sector the challenge remains getting hold of the stuff.  With strong demand from the higher margin consumer sector supplying biodiesel to the marine sector in meaningful quantities simply isn’t a priority for the producers, and it looks to be some years before biofuels of any kind have any sort of measurable impact on the marine world.

What is in plentiful supply in most places, of course, is wind, which is why the owners of sailing superyachts can sit back and bask in the warm glow of the knowledge that they can circumnavigate the world if they wish leaving little more than a carbon toe-print behind them.  The vast majority of superyachts are, of course, propelled by engines rather than sails, but even they can access the free energy source that is wind. SkySails GmbH is currently the leading developer of the technology that uses kites to provide supplementary power to ships and large motoryachts – an idea that has been around since at least the start of the 19th century.  The underlying principle is that wind speeds at altitudes of between 100 metres and 300 metres are typically stronger and more stable than those found at sea-level.

A superyacht of around 100 metres in length can be fitted with a SkySail of between 300 and 600m2 and its associated deployment and control systems and thereby reduce fuel usage by anything up to 50% in optimum conditions with no sacrifice in speed.  The system is not intended for close-quarters island hopping, but for passage-making and ocean crossings it would appear to have a number of genuine advantages.

Wind can be used for more than propulsive energy on yachts, of course, but many owners shy away from conventional wind turbines due to their undoubted unattractiveness and limited contribution to a boat’s energy budget on anything but the largest scale.  However, the new generation of vertical axis wind generators from companies such as quietrevolution in the UK and Bluenergy in the US do away with bladed propellers and instead use helix shaped wind vanes.  As well as having a movement that is much easier on the eye, such designs have the added advantages that the machinery is located in the base, giving it a much lower centre of gravity, and the blades also rotate in much lower wind speeds than their conventional rivals.


3.  Energy conservation

So far we have looked at ways of generating power more efficiently, and with fewer emissions, but the flip side of going green afloat is identifying ways in which superyachts can reduce the amounts of power that they use without any loss in comfort or amenity.  Air conditioning is typically a major user of power in large motor yachts; and while the new types of solar control glass that are now on the market can help reduce the heat that enters the internal space on a large yacht, as can the use of heat reflective paint on the hull and superstructure, they do not eliminate the need for climate control when a boat is in a tropical or sub-tropical environment.  Recent studies have, however, highlighted the role that passive solar cooling and heating using convection can play in regulating internal temperatures, particularly in the very largest motoryachts.

"The principle is a simple one,” explained RSD exterior designer Sam Cuson, “and requires no energy generation, and has no moving parts apart from the air itself.  The cooling process works on the basis that warm air rises, and so is at its most effective at night when the air within the yacht is warm, but outside is much cooler."

By having two sets of vents, one as near to sea level as possible to draw in the coolest air, and the other at the highest point in the superstructure where the warm air collects, the warm air can be released to the outside with the resultant drop in internal pressure sucking in the cool night air to replace it.  The principle can also work in the day with the vents on the shady side of the yacht being opened.  The greater the difference in height, the more effective the process. 

To efficiently heat a boat in higher latitudes using available natural sunlight, the requirements are thermally efficient glass to trap the solar energy once it is inside the boat, internal walls and structures made of materials that will store the heat and release it slowly in periods of low sunshine, and movable louvres that can be adjusted to regulate the amounts of sunlight permitted to enter.


4.  Waste management

With often large numbers of crew and guests living on board, large yachts can generate substantial quantities of waste.  The vast majority recognise the need, and have the facilities, to retain that waste until it can be disposed of in a responsible fashion, but in their study Rainsford Saunders Design took that a stage further and incorporated a number of technologies that enable a large yacht to process its own waste, thereby both reducing the pressure on shore-based infrastructure and greatly reducing the storage space given up to waste.

Organic waste for example can be bulky and awkward to store, but with the installation of a hydraulic press the subsequent removal of the liquid element can dramatically reduce both its volume and weight and enable it to be stored in a dry and odour-free form.  The water that is extracted can then join other grey water outputs such as those from showers, laundry and the galley and be sent to a water recycling facility that typically will use either biological or distillation processes to separate the purified water from the residual elements.  Elsewhere on board non-organic waste can also be compacted for high density, low volume storage while awaiting onshore disposal.


5.  Leaving behind nothing but a (minimal) wake

“Of course for a yacht owner to adopt the whole ethos of environmental responsibility he or she needs to look beyond the microcosm that is the yacht,” added Rupert Mann.  “Many environmentally sensitive locations, for example those with coral reefs, already restrict access to visiting yachts due to the damage they can do with their anchors or simply the wash from their passage.  These locations are likely to become more widespread, and the criteria governing them ever tighter as authorities seek to protect or regenerate environments that are a valuable economic resource as well as something worth defending in their own right.  For large yachts to gain access to such places they will increasingly need to be able to demonstrate that they have a zero impact on their surroundings and the capability to internalise any emissions or waste that they cannot avoid generating. It will undoubtedly involve greater expense in design and construction, but for most it will be a price worth paying.”


6.  Conclusion

The technologies described above represent just some of what a yacht owner in conjunction with his design team can achieve.  The RSD research programme turned up a wide array of small scale products that would further contribute to a yacht’s sustainability objectives, ranging from fake rare wood veneers that, once they are printed on to a lightweight substrate and coated with a thin layer of clear epoxy, are indistinguishable from the real thing, to biodegradable fillings for mattresses and upholstery produced by companies such as Natural Mat in the south west of England.  All these and more demonstrate that there is a great deal that can be done providing that the commitment to achieving a minimal environmental impact is there right from the beginning.

However the perceptions of owners and the industry change over the coming years, superyachting will never be the most environmentally-friendly activity.  Even with the most sophisticated power-generation and recycling systems, the consumption per head of materials and resources in both construction and operation are simply too great to make it anything but a luxury of the highest order.  Yet this ability to command access to the very best also gives superyacht owners the capability to take a leading role in the nurturing and development of the emerging technologies that will eventually enable us all to coexist in some sort of balance with the other inhabitants of our small planet. 

"Someone has to push at the boundaries of what is achievable,” said Rupert Mann, "and we hope to convert something that is currently a novelty into the mainstream.   Who knows, maybe superyachting will yet surprise us all with the scale of its contribution to the task of creating a cleaner world."

Boat International
November 2008

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