Sailing hybrids - The shape of ships to come?
The escalating cost of fossil fuels coupled with tightening environmental regulations are hoisting hopes for a return to the age of sail.
There can surely be few things more exhilarating than the sight of a three-mast clipper fully rigged. On the tea run from China to Europe these majestic vessels could reach speeds of 16 knots.The demise of this one-time nautical mainstay was heralded by the ‘Panic’ of 1857, the first global economic crisis to hit the industrialised world, and the final nail in the coffin was delivered with the opening of the Suez Canal 12 years later. The age of sail was over and steam power ruled the waves.
But increased environmental legislation within the cargo shipping sector has reawakened interest in the economic possibilities of wind, and a number of companies are venturing to develop modern sail-powered cargo ships.
B9 Shipping of Antrim, Northern Ireland is working on a 3000dwt (deadweight tonnes) dry bulk carrying vessel. It is a lucrative potential market with over 10,000 vessels of that tonnage plying their trade around the globe. The company is backed by an encouraging market assessment, which shows a sector requirement based on the impact of fossil-fuel prices, the pending carbon cost coupled with the new emissions regulations.
“We are looking at something that has to be future proof as well as being commercially viable today,” says Diane Gilpin, development director at B9 Shipping. “We will start moving commodities and then [progress] on to wet bulk at some time in the future and then passenger vessels, but the original demonstrator will be a dry bulk carrier.”
Gilpin was part of the team that brought Cellnet to the UK telecommunications market. She went on from there to work in Formula One where transferring technology from race track to the commercial sector was a key aspect of the work. Seeking a healthier environment she moved into yacht racing where the technology transfer from blue-water racing to commercial shipping was under-exploited.
One particular area of interest for B9 is moving biomass. Wood pellets are being imported at the rate of several hundred thousand tonnes a year to support the development of renewable energy in the UK. These are currently arriving on traditional fossil-fuelled ships, which, as Gilpin explains, is a real paradox. “The logic of using renewable energy to move renewable energy makes the entire supply chain more resilient,” she says.
How will it work?
The propulsion for the three-mast ships will be a hybrid arrangement with the dyna-rig automated sail system backed up with a Rolls-Royce LNG engine. “We never really considered a sail-only vessel because in the modern world we are used to having our goods delivered when we want them,” Gilpin adds. “If the wind doesn’t blow, saying the weather wasn’t right isn’t enough. So we decided that a hybrid design was the way forward.”
For the sailing rig the team have opted for the tried-and-tested Dyna Rig set-up, pioneered in the 1960s by German Wilhem Prolls. “The Dyna Rig is essentially an unstayed squaresail rig,” says Rob Humphreys, lead designer on the project. “It is conceptually similar to the rigs that covered the oceans centuries ago. The advantage of being unstayed is that the yardarms can be articulated further to generate better aerodynamic properties, and of course dramatic improvements in material technology transform the lift:drag ratio of the individual sails.
“The ability to handle variable conditions is met by an automated ability to reef individual sails, reducing sail area as required, but also controlling the aero/hydrodynamic balance of the ship to minimise resistance at all times.
“Of course, aerodynamic refinement is one thing: a B9 ship will need to be robust and easy to maintain, and foremost in our thinking is the need for an industrialised approach so that the Capec cost, service cost and general efficiency are optimised towards a viable commercial solution.”
The engine - B9 refers to it as an auxiliary engine - runs on liquid bio-methane, which is derived from waste food that is put through a process of anaerobic digestion. “We propose to liquefy it and inject it into the LNG network that will be emerging for the shipping sector,” Gilpin says. “In reality we will be using LNG for the engines, but for the certification process the amount we are putting in will match the amount of bio-methane that we are putting into the network; this is exactly the way the green electricity certification programme works.
“The phenomenal potential for hybrid power in motor sailing has yet to be explored. We can run the engine to get the hull moving through the water and then use the sail. It is not a binary system; there is an off engine and off sails. But there is also this area that we can refine and develop and we go through the analysis around the sweet spot for using motor and sail in tandem.”
To date a model has been tested in the tank at Southampton University as well as a wind tunnel test for the rig. “We have just about finished analysing the data from that,” Gilpin adds. “We ran a model of the hull design in a towing tank and analysed its performance in various sea states. We also took the rig into a wind tunnel to test it under different strengths and directions of wind. We put all of this data together to look at the holistic design on how the rig works with the hull.”
That data was crunched on several routes from potential customers and the timings and costs compared with conventional vessel performance utilising weather information supplied by the Met Office. “The result was that we would reduce the fuel use by 50 per cent while matching shop speeds, and that is with a sub-optimal design,” Gilpin says.
The plan for the next year is to further test the models to give comfort to stakeholders and potential customers in the market. “Whilst it’s proven technology and a system-integration job, it is a fairly big leap of faith for a big, long-term capital asset,” Gilpin explains. “So over the next two years we will develop the design concept, put it through further rigorous testing in the tank and tunnel and then run much more detailed economic analysis using comparable cargo on comparable routes so that we can give customers the confidence that it has been robustly analysed.”
Tres Hombres: Return of sail
In its home port of Brest the sight of the 32m, Tres Hombres, trimming its sails and heading out to sea has been a common sight since 2009. But the bigantine is no leisure craft plying its trade amongst Brittany’s vibrant tourist industry but a fully working cargo ship.
Capable of carrying 35t of goods Tres Hombres cruises between the Caribbean and Europe carrying rum, cocoa and coffee. It is one of three ships run by eco carrier Trans Ocean Wind Transport (TOWT), the others the 23m zulu Leenan Head and the 21.7m gabare Notre dame de Rumengol work the European routes.
“Wind propulsion will play a great role in the future. If not in two years’ time then in 22 years,” Guillaume Le Grand, the founder of TOWT says. “In the 21st century [traders] will have to rediscover sail and capitalise on new technologies now available to make it efficient.
“Just two years ago sail shipping was regarded as something for lunatics, just as organic food producers were dismissed as crazy 40 years ago. But retailers are now showing great interest in sail-shipped goods. We’re building something out of the blue. It’s important to have something concrete now to make decision-makers understand it does exist and that we are in need of support and a technology break.”
Ecoliner: A concept in wind
Less of a realistic commercial project the Ecoliner from Dykstra Naval Architects is more a conceptual project. The challenge is to create an 8000dwt (deadweight tonnes) multi-purpose cargo vessel capable of sailing a transatlantic route.
The Ecoliner concept can reach about 18 knots under sail, depending on the cargo, wind speed and angle, although the chosen design speed is 12 knots. In operation, the route and speed will be optimised by a routing algorithm, which ensures it arrives on time while minimising fuel consumption. When the sailing speed is less than specified by the routing algorithm, an electric motor will be engaged.
One feature of the hull is the ability to resist the side force of the sails. This requirement calls for a hull shape and appendages that provide sufficient lateral surface. The placement of lateral surface affects the rudder balance under sail and on the manoeuvring capability of the ship.
There are still various rig setups are under consideration. The rig naturally influences the sailing performance but also the rig cost and the effect on cargo capacity and handling must be investigated.
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