Buquebus’ second LNG dual-fuel fast ferry will be larger than its sister Francisco, and deploy engines rather than gas turbines
Tasmania’s Incat shipyard is building a dual-fuel 130-m vessel which will be the largest ship the yard has built.
In May 2019, the shipyard inked a contract for a 130-m catamaran that will see service between Argentina and Uruguay for ferry operator Buquebus. Incat’s largest-ever catamaran will weigh in at around 14,000 gt and carry 2,100 passengers and 220 cars. LNG-powered, the four dual-fuel engines will drive Wärtsilä waterjets.
The ship follows Buquebus’ LNG dual-fuel ferry Francisco, delivered by Incat in 2013.
Incat chairman Robert Clifford told Passenger Ship Technology that the shipyard was well underway with the design, with aluminium cutting expected to be carried out before the end of this year. He says “It will be the largest we have built, 30 m larger than Francisco. But it won’t be the fastest, as normal service will be 20 knots, although it will be capable of 40 knots.”
He explained this is so it can act as a relief ship for Francisco, which is capable of 50 knots service speed.
The ferry will be powered by four Wärtsilä dual-fuel engines, a contrast to Francisco, which is powered by gas turbines. This is because speed is of lesser importance as the new ferry will normally be on a much shorter route to Colonia from Buenos Aires, Mr Clifford explained. “The slower speed will allow more time to shop in what will be at 3,000 m2 the largest duty-free shop afloat,” he says. Indeed, the shop will be three times as large as it is in Francisco, which also has capacity for 1,000 less passengers than the new ferry.
“The superstructure of the new vessel will be twice as large, but there will be a similar layout and the average passenger will feel at home, with the same interior architect and the car deck will be the same. The shop will be very similar, albeit on a much larger scale,” says Mr Clifford.
The size of the new vessel means Incat will bring in an extra 200 workers to handle it over the two years it will be built, boosting workforce from 550 to 750.
Speaking about one of the main differences between the new ferry and Francisco, using dual-fuel engines on the former as opposed to turbines on the latter, he said “Turbines are not needed because it is not necessary for the new ferry to go very fast, with a normal speed of around 20 knots. Turbines are useful for 50 knots but not necessarily with speeds at 20 knots.”
Furthermore, the route of the new ship includes a lot of shallow water with a draught of only 2.5 m.
Incat selected the engines. “Wärtsilä are well known for their dual-fuel engines and that was the logical engine to use,” Mr Clifford said.
Perhaps the greatest challenge of building the new ferry will be the size of the two LNG tanks to be used. These are being arranged by Wärtsilä and being built in China.
“The fuel tanks are very large and heavy – each one weighs 90 tonnes,” Mr Clifford commented.
“The fuel itself is kept at -250°C and the tanks have to be insulated to keep it as a liquid. We need to take early delivery of the tanks because we need to build the ships around them. They are so large they cannot easily come out again.”
The tanks will be placed mid ship in the hulls, at or below the waterline.
Due to the weight of the tanks, Mr Clifford said it is important for the shipyard to make everything as else as light as possible.
Waterjets, to be provided by Wärtsilä, will be deployed. Mr Clifford says “Waterjets are necessary because of the shallow draft – large propellers would scour the bottom and do damage. We are using Wartsila waterjets, as we have done in previous vessels we have built.”
He added that the maneouvrability requirements are normal for a catamaran. “None of that will be a problem, it is not that unusual a vessel, but for its large size, shallower draft and the fact it is gas powered.”
Commenting on the refuelling of both of Buquebus’ vessels, Mr Clifford says “The use of LNG has been a successful development for Buquebus. They now have their own delivery trucks and the first ship is refuelled each day from their own liquidisation plant. This will be modified only a little to process enough LNG for the new ship.
Indeed, Buquebus bought a piece of land 60 km away from its Buenos Aires ferry terminal which has a pipeline running beneath it, bringing gas to the city. Buquebus is taking gas from the national grid and transforming it for use in the LNG plant. Passenger Ship Technology previously reported that seven containerised LNG packs with adjustable output take the natural gas and convert it into LNG. This process avoids any boil-off of the gas, so there is no pollution throughout the entire process.
Speaking about the fuel deployed, Mr Clifford said “The main challenge is the tank and you do not want the tank too big – you only want enough to satisfy the day’s work. Therefore Buquebus will refuel every day, the first boat every afternoon and night and this new one at least once a day, so the ferry does not carry too much LNG.”
He added “It is no more difficult to handle than other fuels and safety wise it is not an issue, there are things to learn but nothing special. The intention of Buquebus is to use LNG and only use MGO as back up.”
But he pointed out that MGO would be used to get the ferry from Tasmania to South America as there wasn’t enough gas capacity for such a long journey.
As well as being environmentally friendly, the gas is attractive to operators as it is around half the price of MGO.
Mr Clifford sees LNG as making large inroads into the fast ferry sector. “There is no doubt about that, and we are currently speaking to customers about several such projects. There will be fast ferries running on LNG in Europe.”
Incat is also working on a couple of projects that use batteries. Indeed, Mr Clifford makes the point that Buquebus’ newbuild could have used batteries, if electric power had been available to the ferry operator.
“Batteries will come to the fast ferry sector,” he says. “The use of battery propulsion for a ferry across the English Channel would be quite useful as it is only a half-hour voyage.”