Finnish icebreaker Nordica assisting a merchant ship near Hamina, Finland, on 28 February 2009. photo by Cornelia Klier
A bit of news that may be indicative of things to come.
The Associated Press, via the SeattlePI, reports. the Finnish multi-purpose icebreaker Nordica. has made the earliest transit of the North West Passage on record. “Setting off from Vancouver on July 5 and reaching Nuuk, the capital of Greenland, on July 29.”
That is a journey of 6000 miles in 24 days for an average of 250 miles per day or 10.4 knots.
Nordica is not a particularly powerful icebreaker with four engines totaling 21 kW or about 28,000 HP, smaller and slightly less powerful than USCGC Healey’s 22.4 kW.
Chuck Hill's CG Blog 
Correction: Nordica has.a propulsion power of 15,000 kW (2 x 7.5 MW electrically-driven azimuth propulsion units), compared to Healy’s 22,400 kW (two 11.2 MW propulsion motors and shaftlines). Both have four main diesel generators and 21,000 kW sounds about right for Nordica; can’t remember what Healy has.
According to Wiki the Healy’s diesels total 34,560 kW.
https://en.wikipedia.org/wiki/USCGC_Healy_(WAGB-20)
That’s quite a significant reserve. Depending on the mission, it allows you to either carry out maintenance of part of the power plant while underway or continue mission at full propulsion power even in the event of sudden engine failure.