seatec - Finnish marine technology review 1/2017 | Page 30

The vessel has been equipped with a combination of classic qualities .

2 x 6 500 kW at the stern and 1 x 6 000 kW in the bow .
” This type of propulsion arrangement is rather unique in ships ,” Mustamäki expects .
” Icebreakers have been equipped with bow-mounted propellers even in the past , but those could not be rotated to any horizontal angle as in the case of Polaris .”
LNG FUEL FOR BETTER ECOLOGY
The new icebreaker has a length of 110 metres and a width of 24.4 metres . The ship is the ninth icebreaker in the fleet of the state-owned Arctia Oy .
” Overall , it has taken more than 500 man-years to build the ship ,” says Mustamäki .
The ship is the world ’ s first icebreaker to utilise LNG fuel ( liquefied natural gas ). Both of the ship ’ s LNG tanks have a capacity of 400 cubic metres . Marine diesel oil can be used as an auxiliary fuel .
Polaris has been equipped with a diesel-electric power plant and propulsion system . The main engines are the 2 x 6 000 kW , 2 x 4 500 kW and 1 x 1 280 kW Dual Fuel engines manufactured by Wärtsilä .
” The Finnish Transporst Agency can fill up the ship ’ s tanks with LNG fuel at various ports by utilising a fuel truck ,” Mustamäki mentions .
For the first sea trials , the ship was fuelled up at Port of Vuosaari in Helsinki .
Polaris conforms to the IMO ’ s forthcoming international Tier III emission requirements , as well as the special Baltic Sea regional requirements for limiting sulphur emissions .
Further old icebreakers in the Arctia ’ s fleet are to be replaced by newer ones by the year 2029 . The total cost for the fleet renewal has been estimated to be close to 1 billion euros . n
Both of the ship ’ s LNG tanks have a capacity of 400 cubic metres .
30 seatec 1 / 2017