Ship design in the modern era has become steadily more and more scientific and mathematical, steadily superseding time-served traditional methods of working to a set of principles and then building a model (or succession of models) to make sure the vessel meets design intent.
The arrival of computers and their growing sophistication has taken the strain when it comes to number-crunching and complicated calculations – and a more recent development in the IT world, computational fluid dynamics (CFD), now allows designers to optimise the design of hulls and their interaction with the water by comparing a wide range of parameters and predicting operational performance.
New or improved designs arrive more quickly, with water tank testing used to verify that the computer-generated data and predicted performance have been accurately captured in the final physical design.
CFD technology itself continues to develop and grow in power too, which means today’s and tomorrow’s designers of ships and marine equipment have not simply a new tool but a whole new toolbox that radically increases the speed, accuracy and comprehensive scope of their work.
Recognising these benefits, Rolls-Royce has always employed CFD as fully as possible within all of its businesses – with its marine designers using it for ship design, propulsor development and a range of other applications. Though extensive use is made of commercial software, the company also develops its own codes for specific technical areas of interest.
And Rolls-Royce is also leading an EU-funded technology programme, Streamline, which in today’s environmentally-conscious world is investigating radically new propulsion concepts and systems. A central raft of the research – which was launched in 2010 and scheduled to run until 2014 – is to develop advanced CFD tools that can simulate, analyse and optimise the hydrodynamic performance of these new propulsion concepts.
CFD is an increasingly powerful and flexible tool for both innovative research into future designs and the very real world of today’s shipping projects.
It can develop new products and refine existing ones, ensuring the in-service realisation of performance predictions; it can evaluate alternative shapes, positions, hull forms and integrated propulsion systems to ensure optimum water flow. This is important in meeting overall vessel efficiency goals required to meet prescribed Energy Efficiency Design Index (EEDI) targets.
And more and more variable design factors can be stored in the computer databases, such as the effects of wind on various ship types and configurations, including the secondary effects of on board equipment such as cranes, helicopter decks and other superstructure. Wind tunnel testing then validates resulting calculations.
Such detailed data is another vital contribution to the CFD databases that help ensure that individual vessels move, manoeuvre and position themselves precisely as they are designed to do.
Ready for the LNG revolution
The marine industry relies on fuel oils for almost all current powering needs, but tighter emission regulations and the need to go ‘green’ are starting to convince vessel operators to consider the alternatives. That’s where Rolls-Royce is in place to help.
Liquefied natural gas (LNG) is being widely hailed as the marine fuel of the future. For Rolls-Royce, engines fuelled solely by natural gas have been in production since 1991. Since the introduction of the Bergen lean burn technology more than 650 gas engines have been delivered for operation on land or at sea. More than 23 million running hours of experience have been accumulated.
Exhaust emissions from ships came into sharper focus because of national and international antipollution rules phased in since 2005. As emission control areas (ECAs) were introduced in the Baltic, North Sea, and later the United States, the hunt was on for cleaner fuels.
Deep sea vessels have mainly used heavy fuel oil (HFO). In the late 1970s the quality of this fuel deteriorated as crude oil was more intensively refined for valuable fractions, and ships were encouraged to burn the cheap residue, the engine manufacturers working hard to develop engines capable of using it. High sulphur HFO is not usable in ECA areas around many coastlines without expensive exhaust cleaning systems.
The rules for using light distillate liquid fuels are also becoming stricter, with a probable increase in fuel price as the forthcoming SOx restrictions will encourage a higher uptake of ultra low sulphur fuel. Nitrogen oxide emissions are also very much in focus, with states increasingly imposing penalties. In the case of Norway, a tax on NOx emissions has been given a positive aspect by turning tax into a fund, which is used to encourage NOx reduction measures, subsidising and rewarding practical reductions.
With the use of liquid fuels for marine propulsion becoming more expensive and problematic, attention has turned to LNG. LNG is mainly methane, and its chemical composition leads directly to lower CO2 emissions. LNG is also virtually sulphur-free. With suitable engine technology, NOx emissions are also dramatically reduced, and the gas burns cleanly without smoke and with few particulates. It is now more abundant than oil and less expensive, although its price compared with liquid fuels varies around the world.
It is projected that this differential on an energy equivalent basis will continue, and may even increase.
This has opened up an opportunity for significant fuel cost savings for operators. When the shipping industry began to take an interest in LNG, Rolls-Royce was there with well proven medium speed engine technology.
Design for Life - Bergen B33:45 diesel engine
Introducing the Bergen B33:45
A new family of medium speed diesel engines producing 600kW per cylinder maximises the integration of today’s technology to reduce operating costs.
Developed to be more powerful and efficient as well as extending service intervals, the new Bergen B33:45 harnesses today’s technologies to the full.
- Reduced life cycle costs was the number one design objective, which resulted in five clear goals.
- Lowest fuel consumption and the highest power per cylinder in class
- Dynamic/extended service intervals
- Increased power within the same footprint
- Compact modular design
- Base engine suitable for liquid and gas fuel
The ship designer and shipyard can use to advantage the new engine’s compactness and ease of installation.
600kW per cylinder
The new B33:45 comes with a 20 per cent increase in power per cylinder compared with current B-series engines.
Bore is 330mm and stroke 450mm. CFD analysis of the combustion process was undertaken together with the MTU R&D centre in Friedrichschafen.
In-line engines are the first to be produced, with V engines to follow later. In-line six, seven, eight and nine cylinder units span a power range from 3,600 to 5,400kW and V engines 6,000 to 8,400kW.
Low fuel consumption
Specific fuel consumption is 175g/kWh at 85 per cent MCR and 177g/kWh at full load.
The engine control system is the electronic engine management system from MTU which is developed in-house. It monitors and controls all key engine functions and exhaust aftertreatment.
A totally new turbocharger is matched to the exhaust system which provides multi-pulse charging with charge air taken through a two stage intercooler, which gives a high turbo efficiency. Modular design has been applied throughout for ease of maintenance.
Looking more closely at the design of the B33:45, the foundation is a more rigid SG iron block than the current B-series, which has reduced vibration levels to 10-11m/sec. It supports the balanced crankshaft which is the same for both propulsion and generator applications. Cylinders are individual units that can be removed complete within a service height of 2.52m above the crankshaft centre-line. Connecting rods are of the marine three-piece type allowing piston removal without disturbing big end bearings. The strengthened camshaft design has one section per cylinder for ease of replacement.
Another feature is a reduction in the amount of external pipework, that ensures a safe, yet simple fuel system design. This has been achieved by putting the oil bores into the cylinder heads and the passages are joined by simple transfer blocks. The system is common rail ready, with the conventional system providing maximum flexibility for different applications.
Meets IMO Tier III
Meeting IMO Tier III NOx emission requirements was another important goal and is achieved with selective catalytic reactor (SCR) technology. The system uses urea to convert the NOx into nitrogen and water vapour. An SCR system was part of the development programme and NOx levels within IMO levels have been successfully validated running from 10 – 100 per cent load. The control unit is integrated into the engine controller and compact SCR units will come in various sizes to match the engine power selected.
Extended maintenance intervals
The B33:45 family is designed for 25,000hrs between major maintenance when operating at average loads within a specified window. This enables major engine maintenance to be alined with the vessels reclassification intervals, normally every five years, which significantly reduces vessel down time. When overhauls are finally needed owners can benefit from the Bergen worldwide exchange pool system which offers cylinder heads, injection components and other parts by exchange and later return, with warranty.
Pulling power - the tale of two tugs
At Statoil’s Kårstø gas processing terminal, north of Stavanger, the LNG-fuelled tug Borgøy has been operating successfully now for about six months, escorting hazardous cargoes in and out of the terminal. It was recently joined by sister tug Bokn, which went to work immediately upon arrival. Both the owners and charterers have expressed their satisfaction with the tugs’ performance so far.
The world’s first LNG-powered tugs made the delivery voyage from the Sanmar yard in Turkey to Norway, refuelling LNG from road tankers at planned locations on the way. Both tugs are owned and operated by Buksér og Berging, headquartered in Oslo. The company was founded in 1913, specialising in towage and salvage, mainly serving the Norwegian, Danish and Swedish markets. It has been involved in escort towing at tanker terminals since the concept was first introduced, and has pioneered new designs of escort tugs in its own design department.
The company now operates at seven Scandinavian terminals, performing around 1,500 escort jobs and assisting around 4,500 vessels every year. The two Kårstø tugs represent the latest Buksér og Berging design thinking in z-drive azimuthing tugs, with systems designed around using LNG as the sole fuel. When the towage contract at Kårstø came up for renewal it was Statoil, the terminal’s operator, which favoured LNG for the tugs instead of diesel. Environmental impact was very much the driver. Buksér og Berging won the five-plus-five year contract by offering the LNG option. Rolls-Royce gas propulsion specialists worked closely with the tug owner’s staff and the shipyard to meet Statoil’s requirements, while satisfying international and DNV-GL rules on gas craft construction and safety measures. Specialist training is also part of the gas propulsion system package, with courses held at the Rolls-Royce training centre in Ålesund and the Bergen factory.
Borgøy and Bokn are to the same design. The 35m long, 15.4m beam hull incorporates a foil-shaped keel built into the bow and runs about three quarters of the length aft, enhancing the tug’s effective side force when operating in indirect mode, where the tug sets itself at an angle to the ship to act as a brake. Two Rolls-Royce US35 azimuth thrusters with 3m dia CP propellers and nozzles are shaft driven by two Bergen C26:33L6PG engines. The engines together produce 3,410kW running at 1,000rpm and also drive the hydraulics and firefighting pumps.
Gas is carried in a single vertical cylindrical insulated tank holding 80m³ of LNG, which is fed to the engines at about 35°C and 6.5 bar via two entirely separate gas supply systems. Operating safety is paramount. With separate drivelines and gas supply systems, double-walled gas pipes in the engine room and monitoring by the Rolls-Royce ACON safety, alarm and control system with gas detection in all areas, propulsion redundancy is assured, a critical factor in escort tug work. Any leaked gas is led to vent pipes high above the foredeck, a noticeable visual difference that marks these tugs out from the conventional diesel.
A bollard pull of 65 tonnes is available, and the towline pull can be increased to in excess of 100 tonnes in indirect mode by using the keel for extra force to stop or turn a tanker. The new tugs do their job as planned. Apart from the specialist training, the learning curve has been normal. The main question at the planning stage was whether the response of gas engines to rapid changes in load would be good enough. Fears were unfounded. ”The engines are very responsive. We are happy,” says Arild Jaeger, CFO of Buksér og Berging.
Satisfaction is also apparent on board Borgøy, where Captain Martin Knape demonstrates the tug’s capabilities. He says the LNG-fuelled tugs respond as well in operations as their diesel counterparts. Bunkering is required every five or six weeks, depending on the number and size of vessels to be handled at the terminal. LNG is transferred from road tankers, which takes less than an hour. The indications are that Borgøy and Bokn will showcase the same efficiency, operating cleanliness and low service requirements as other Bergen gas powered vessels.
The Kamewa stainless steel series waterjets continue to evolve.
The Kamewa mixed flow waterjet pump is already an efficient device. Intensive CFD & FEM analysis has signifiicantly improved propulsive efficiency, especially in the 30-40 knot speed range. The new Steel-series Kamewa waterjets provide improved efficiency over a wider speed range.
Steel series waterjets can be supplied in three configurations to suit the owner and yard preference:
- A skid mounted unit in steel, aluminium or FRP – a simple to install baseplate with transom and all waterjet components installed as a unit that can be bolted into the hull aperture
- Inlet duct with mounting, with waterjet pump and manoeuvring system shipped as a separately.
- Pump and manoeuvring system as a unit, with drawings for the inlet for shipyard build.
The new waterjet range is designed for easy and infrequent maintenance. The mean time between overhauls is up to 15,000 hours or five years. Hydraulic cylinders and feedback sensors located inside the hull simplify maintenance and minimise the risk or oil leakage to sea. The shaft seal is a robust unit made of duplex stainless steel for corrosion resistance, so zinc anodes are not needed for some models. The offer the best combination of performance, capital cost and economical operation.
Kamewa waterjets have now been standardised into two product families, steel and aluminium. Steel models have mixed flow pumps with a stainless steel impeller and well proven aluminium jets have axial flow pumps with a stainless steel impeller. The new range includes the former A3 series, now the smallest models in the steel family. It starts with the 25 and spans 19 frame sizes with powers from around 450kW to over 30,000kW.
Safer operation from the bridge
Shipbuilders Astilleros Gondan have worked with Rolls-Royce since the 1990s to build fishing vessels from their yard in northern Spain. But they are now building a UT design for the first time. With competition becoming more and more fierce, Iván Artime Díaz – Project Director, Astilleros Gondan, S.A. knows that they have to offer customers flexibility as well as quality.
The concept of the ‘unified bridge’ is one way that Astilleros Gondan is meeting those challenges. In a first for the offshore market, they are fitting their UT vessel with this advanced control system for their customer Simon Møkster. Ship operators in the past had to work with many different pieces of equipment. Now with just a few consoles on the bridge, their jobs have become not just easier but importantly, safer.
With engineering details such as this, not only Rolls-Royce, but also adaptable shipbuilders like Astilleros Gondan, have a clear advantage in the offshore market.
Within arms reach
The new bridge set-up covers more panels and functions within arm’s reach than the previous set-up. The maritime classification rules list vital equipment that has to be within these zones and the new set-up fits more equipment in closer proximity to the user.
The vessel is designed to pierce through the waves under harsh weather conditions, making it possible to keep a more constant speed, reduce the use of fuel and increase on board safety.
What will ferries look like in the future?
Like any diligent business, Rolls-Royce delivers a view of the future for customers by maintaining a strong focus on the future requirements for key market sectors. The Rolls-Royce Blue Ocean team investigated how ferries of the future are likely to look and operate – and th team emerged from its study with some innovative answers.
Using a typical ferry mission as its baseline – a 120 nautical mile route in an Emission Control Area (ECA), operating at 19 knots – the team generated two design concepts, code named Clear Blue and Dynamic Blue.
Clear Blue takes a minimalist approach in terms of ship design, while Dynamic Blue seeks to enhance the passenger experience while minimising operating costs. Importantly, both aim to deliver strong economic benefits to future ferry operators, reducing fuel consumption and delivering energy savings of up to 25 per cent.
The Clear Blue concept fundamentally aims to minimise initial capital costs low by removing non-essential elements and simplifying other on-board features. This 24,500-tonne, 152-metre long design has a wider profile, allowing extra vehicle lanes and U-turns as all vehicle movements are over the stern and there is no moving ramp.
It also incorporates a high degree of modularisation to reduce build costs. Two decks of cabin blocks – containing all passenger facilities including restaurant, bar and shop – are installed on rather than inside the hull. This allows them to be installed as modules pre-outfitted with heating, ventilation and air conditioning and other auxiliary services.
Stores for each voyage are brought aboard and parked alongside the galley in refrigerated containers, which eliminates the need for unloading and on-board stores.
Clear Blue’s main propulsion centres on a 7,600kW Bergen B35 series gas engine driving a single controllable-pitch propeller through reduction gear equipped with a hybrid shaft generator. Two 3,700kW gas gensets provide electrical power, and aft of the propeller is an electrically-driven Azipull thruster that provides vectored thrust for nimble manoeuvring, augmented by two bow tunnel thrusters for extra agility.
Liquefied Natural Gas (LNG) road trailers – suitably anchored to the open deck centrally aft – will take the place of internal gas tanks. This further underlines the guiding principle of Clear Blue based on minimising complexity, on-board installation and construction costs.
The second concept developed by the Blue Ocean team, Dynamic Blue, takes a different approach by utilising technology to reduce operational costs while maintaining passenger comfort.
This 27,500-tonne, 170-metre long vessel embodies a novel non-symmetrical layout, with services, shopping and deck-to-deck access concentrated on the port side, leaving the starboard side uninterrupted for passengers and the various on-board facilities they want to use. This part of the deck is cantilevered out over the lower decks, with a glazed roof, providing extra light and a spacious feel.
For propulsion, four engines use LNG bunkered in two fixed tanks. A single 7,600kW Bergen engine drives the central shaft connected to a Promas integrated propeller/rudder. Two electrically-driven Azipull thrusters flanking the main propeller can be used to augment propulsion in transit or for manoeuvring.
Three 3,700kW Bergen gensets supply electrical power, and a waste heat recovery system improves efficiency further still. The overall configuration allows the crew to ensure optimum performance by selecting mechanical, electrical or hybrid modes according to operating conditions, and the LNG fuel additionally provides cooling for ship’s services.
Both designs are expected to carry around 1,000 passengers with Clear Blue containing 128 passenger cabins and Dynamic Blue 166 cabins. Comparison studies indicate that the cheaper-to-commission Clear Blue design will produce an annual energy saving of 15 per cent, while Dynamic Blue will save 25 per cent compared to the baseline vessel.
Norwegian ferries set new standard
Two new LNG-fuelled ferries powered by Rolls-Royce engines are setting new standards of comfort and efficiency on a route between Norway and Denmark.
“We are delighted with our two new vessels – the MS Bergensfjord and MS Stavangerfjord,” says Fjord Line’s President and Chief Executive Ingvald Fardal. “They put us in a sound competitive position and we have only positive feedback from our customers who appreciate the fact that the ships are much quieter than conventional vessels.”
Linking Bergen and Stavanger with Hirtshals in northern Denmark, the 1,500-passenger cruise ferries then call in Langesund on Norway’s Skagerrak. The two ferries each have 306 cabins and capacity for up to 600 vehicles.
With hulls built in Poland, the ships were outfitted at Bergen Group’s Fosen Shipyard in Rissa, Norway. Fjord Line chose gas-only engines from Rolls-Royce rather than dual-fuel propulsion units capable of burning oil or LNG. Mr Fardal explains why.
“We examined various options – in fact, the two ships were originally designed with conventional engines capable of undergoing conversion to LNG power at a later date,” he explains. “But when we looked into it, we found that the Rolls-Royce Bergen engines are more fuel-efficient, more flexible, more responsive and simpler than equivalent dual-fuel engines.”
“For us, though, there was one deciding factor. From next January, all ships operating within the boundaries of Europe’s Emission Control Area (ECA) will have to burn fuel with a sulphur content of less than 0.1%,” Fardal says.
“This means that the owners of conventionally-powered ships will either have to pay a huge premium for their fuel or install costly scrubber technology.”
Mr Fardal continues. “But LNG has a fantastic emissions profile compared with fuel oil and diesel. It contains virtually no sulphur or particulates, nitrous oxide emissions are cut by 90% and greenhouse gas by a quarter. That is why we are seeing LNG propulsion being adopted by the owners of a growing number of ships, and ship types, in the existing ECAs of northern Europe and North America.”
But what about the availability of LNG?
Mr Fardal admits that has proved something of a “catch 22”. LNG bunkering infrastructure has not been put in place until there is sufficient demand. And there are, as yet, relatively small numbers of gas-powered ships in operation, mostly in Norway. However, Norway leads the way on the build-up of LNG bunkering facilities and there is a growing number of supply sources along the country’s coast.At present, the two ferries are supplied with LNG by truck at the Risavika ferry terminal in Stavanger and in Hirtshals in Denmark. But from September, a newly constructed and dedicated LNG pipeline just a few hundred metres away, will feed fuel to the ships in Risavika from the LNG storage terminal there.
Naming ceremony for HMS Queen Elizabeth
Naming ceremony of HMS Queen Elizabeth
Friday 4th July saw the naming ceremony for the Royal Navy’s new aircraft carrier HMS Queen Elizabeth. Built at the Rosyth shipyard in Scotland, and weighing in at 65,000 tonnes she, and sister ship HMS Prince of Wales will be the largest naval ships in Europe. Rolls-Royce is working in an alliance with Thales, L-3 and GE delivering the power and propulsion for both ships.
Our equipment includes the MT30 – the world’s most power-dense marine gas turbine. A pair of MT30s each rated at 36 megawatts, will power these magnificent ships. We are also supplying the giant propellers that measure 7 metres in diameter and produce around 50,000 horsepower. And we’re supplying shaft lines that drive the propellers, the low voltage electrical systems, steering gear and rudders.
Our Neptune stabilising fins, which deploy under the water in rough seas, will steady the ships during aircraft operations.
This was a hugely proud day for the Rolls-Royce team. We congratulate everyone at the Aircraft Carrier Alliance, MoD and the Royal Navy, and we are privileged to have been a part of this historic day.
Thinking the unthinkable
Sometimes what was unthinkable yesterday is tomorrow’s reality. So now it is time to consider a roadmap to unmanned vessels of various types. Steps have already been taken, mainly in the naval area. On the way, certain functions will be moved ashore.
Engine/equipment monitoring and some underwater operations in the offshore sector could be the first. A growing number of vessels are already equipped with cameras that can see at night and through fog and snow, and have systems to transmit large volumes of data.
Given that the technology is in place, is now the time to move some operations ashore? Is it better to have a crew of 20 sailing in a gale in the North Sea, or say five in a control room on shore?
When ‘fleet optimisation’ is considered, the advantages compound. The same person can monitor and steer many ships. As conditions ashore are often preferred, it will also help retain qualified and competent crew, and is safer.
Many facilities and systems on board are only there to ensure that the crew is kept fed, safe, and comfortable. Eliminate or reduce the need for people, and vessels could be radically simplified. Attitudes and ways of working will need to change, but safe operation is possible, particularly for vessels running between two or three fixed points.
Shipping’s approach is usually about complying to regulations in the most cost efficient way while addressing the key cost issues of fuel, finance, cargo handling and crew. They can all be influenced by holistic ship design. In the future, we must not think of a ship as a number of separate processes or systems, but as a whole where all aspects affect the other. Only by thinking the unthinkable can we truly affect costs.
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