Tallink Grupp’s new LNG dual-fuelled fast ferry Megastar has been delivered – and the use of gas is just one of many innovations
Tallink Grupp’s ground-breaking gas dual-fuelled Megastar has been delivered and has set the bar high – the ferry operator says that the fast ferry "will be a symbol for a new era in fast ferry services on the Baltic Sea.”
Meyer Turku in Finland built the 49,000gt ferry, which has capacity for 2,800 passengers. A spokesperson for the shipyard explained that one of the main considerations in the construction of the ferry was the placement of the gas tanks. Meyer Turku has experience of building gas dual-fuelled ferries, as it built Viking Line’s ground-breaking Viking Grace, one of the first ships to use liquefied natural gas (LNG) as fuel. However, there are some differences between Megastar and its predecessor, the most obvious of which is that Viking Grace’s tanks were placed outside, aft. On Megastar they are inside. “This was something that we really needed to consider carefully. It was one of the main points to think about when designing the ship,” said Tapani Mylly, Meyer Turku's communications manager.
The vessel is equipped with two large stainless steel LNG tanks under the main deck, with total volume of 600m³. The tanks and LNG handling system were built in Sweden, at a Linde Group Cryo factory.
In addition to the tanks, the ship’s LNG system consists of two specially designated bunker stations, double-walled vacuum insulated bunkering lines, a large amount of special pipe fittings for safety, two LNG storage tanks and a gas distribution system for supplying the main engines and steam boilers.
All the pipelines for LNG and gas have been built from acid-proof stainless steel in order to avoid corrosion and possible leaks during the long service life of the ship. All the electrical equipment in the close vicinity of the LNG and gas units is certified as explosion-proof. For safety reasons the ship is equipped with a very large number of gas detection sensors, according to a website dedicated to the construction of Megastar.
Megastar has a total of five Wärtsilä 50DF engines, of which three are 12-cylinder and two are 6-cylinder. The engines were manufactured at Wärtsilä’s factory in Trieste, Italy. “The engine capacity is influenced by wind direction, schedules, and ice conditions, for example,” explained Tallink on its Megastar website.
“With the help of different types of engines, the capacity can be optimised as required. The small engines function as adjustment units alongside the big ones. The task of the engineer officer is to assess which engines should be used at any given moment,” said Mika Ojutkangas, general sales manager for Wärtsilä Ship Power.
“Exhaust fumes from Wärtsilä’s 50DF engines contain hardly any nitric oxides, which are particularly harmful when it comes to the eutrophication of the Baltic Sea,” Tallink noted.
The full scope of Wärtsilä solutions on board Megastar also includes Wärtsilä fixed pitch propellers and propeller shaft lines, the latest version of the Wärtsilä SAM Electronics Nacos Platinum integrated navigation system, and external communication facilities. The Nacos Platinum system's combination of integrated voyage planning, monitoring and track control significantly eases the workload for ship navigators while improving navigational safety.
Wärtsilä has also signed a five-year maintenance agreement with Tallink Grupp for Megastar. Under the agreement Wärtsilä will optimise the vessel's performance, enhance its availability and reliability, and improve financial predictability for the customer. The service agreement also covers Wärtsilä's condition based maintenance and online remote support. The agreement includes maintenance and optimisation of the vessel's engines as well as the supply of spare parts and round the clock online support.
“As the ship is dual fuel, the engine is large for a ship of that size - almost the same size as that of a larger cruise ship. This involved lots of work and parts,” explained Mr Mylly.
Another important consideration was weight – especially as Megastar is a fast ferry. While large engines and LNG tanks add weight, this is balanced out by a lighter hull.
Indeed, the hull shape is innovative and very advanced. “We found out in the sea trials that its performance was even better than what had originally been specified in the agreement,” said Mr Mylly.
Meyer Turku designed the ship’s hull using computational fluid dynamics (CFD) tools. Mr Mylly explained: “We tested thousands of different shapes and from this chose a smaller number; in this case 35 shapes. It is one of the crucial ways of making a hull even better.”
The 35 different hullforms were evaluated so that the best and most effective one could be chosen. “After the CFD calculation, the model tests confirmed the very low hull resistance and high propulsion efficiency of the chosen hullform, which make it advanced and environmentally sound. These extremely good hydrodynamic characteristics lowered fuel consumption and emissions to air, minimising environmental impact as well as providing economic benefits for the company in terms of bunker costs,” said Tallink.
The hull shape and the use of LNG are not the only innovative and energy saving features. “All the systems have been optimised for energy saving,” said Mr Mylly.
He pointed out how waste water is stored on the ship to provide heating to the ship when it is in harbour.
Furthermore, the “change from gas to diesel is almost instant, so the ship operator can optimise according to weather and fuel conditions and choose which energy mode to use in order to run the ship at maximum energy efficiency. It is easy to optimise the operation of the engines, as fuel changes are instant,” said Mr Mylly.
With regard to the engines, a statement from Tallink added: “The concept of diesel-gas to electric power enables the ship’s operators to choose the right number of engines that are needed for current weather conditions. This results in high energy and environment savings, because all the engines can be used at their nominal power, where their efficiency is the highest.”
Elsewhere, the Evac Complete Cleantech Solution including vacuum collection, wastewater treatment, dry and wet waste, fresh water and automation systems, can be found aboard Megastar. “Green values, reduction of all emissions, minimising the amount of waste and increasing recycling have been very carefully taken into account in the design of the ferry,” said Evac. The Evac Cleantech systems aboard the ferry include:
- vacuum collection systems (vacuum units, vacuum toilets)
- wastewater treatment systems (membrane bioreactor)
- dry and wet waste treatment systems (incinerator, food waste vacuum collection units, sludge handling system, thermal steriliser unit)
- freshwater generation systems (potable water treatment equipment)
- systems automation.
Comfort was also a priority, for both Tallink and Meyer Turku. Mr Mylly explained: “The comfort level is extremely high, even better than expected, and sound and vibrations are very low so the journey is very smooth.”
Meyer Turku achieved this through the hull shape and through the tests that it ran to look at vibration. The shipyard used machines to generate the same vibrations that would be experienced on the ship's route, and sensors placed all around the vessel. It then tested the vibrations, making corrections as required.
When it comes to the car deck, the ship has two-level loading, where the entry and exit ways are used simultaneously to load or unload the vessel. This makes the process much quicker.
Megastar is co-financed by the European Commission's Connecting Europe Facility programme.