For more photos see http://gcaptain.com/photos-worlds-first-lng-powered-icebreaker-polaris/
ARCTECH has completed the World’s first LNG powered (dual fuel capable, low sulfur diesel or LNG) icebreaker, NB501 Polaris, for the Finnish Transport Agency, and it is currently in sea trials.
The vessel will be able to move continuously through about 1.6 meter thick level ice, to break a 25 meter wide channel in 1.2 meter thick ice at speed of 6 knots, as well as to reach 9…11 knots of average assistance speed in the demanding icebreaking conditions in the Baltic Sea. In open water the service speed will be 16 knots.
Reportedly “It will also be able to perform oil spill response operations, emergency towing and rescue operations.”
Its dimensions are 110x24x8 meters or 361x79x26 feet. Its propulsion comes from three azimuthing propulsors totaling 19kW or about 25,500 HP. Specs here (pdf).
Crew requirements are tiny at 16.
With a 30 day endurance, it does not have the range the Coast Guard needs for Polar Operations, but with 180% more horsepower than the Mackinaw, it would make a great Great Lakes icebreaker. The US certainly has a lot of LNG. Would be good for the environment too. (Of course it would have to be built in the US, but using a foreign design is not a problem for the Coast Guard.)
Thanks to Lee for bringing this to my attention.
Chuck Hill's CG Blog 
Chuck,
I believe that the Finns have been very helpful to the Coast Guard with the Mackinaw as the example. We should continue this relationship.
Polaris is pretty awesome and truly represents the latest in icebreaking technology, just like the client wanted, but it’s definitely not the kind of vessel the USCG should look for polar operations. However, as Chuck pointed out, the bow azimuth solution would be pretty good for Great Lakes operations. Perhaps the 361′ icebreaker is a bit too big, but you can still get good performance out from slightly smaller hull – the Russians are building a 292′ icebreaker with four Azipods and nearly 5′ continuous icebreaking capability. LNG has its challenges, but if it’s taken into account early in the design (and preferrably using experience from designing Polaris), it shouldn’t be an issue.
In case you were wondering what the most advanced icebreaker in the world looks below waterline, Arctech has published a series of photographs in their press kit:
http://arctech.fi/news-and-media/press-images/