Thetis-class ocean patrol vessel belonging to the Royal Danish Navy. (Similar in size to the OPC.) Source: konflikty.pl, Author: Łukasz Golowanow
The September 2018 issue of the Navy League’s Magazine, Seapower, has an article about ice strengthened Patrol Vessels. The entire issue is available on line. You will find the article on page 32.
P570 Knud Rasmussen. The first of three Danish navy Knud Rasmussen-class ocean patrol crafts. Commisioned in 2008. Photo from Flemming Sørensen
The article looks at the Danish Knud Rasmussen and Thetis classes, the Norwegian Coast Guard vessel Svalbard, and the Canadian HMCS Harry DeWolf class Arctic Offshore Patrol Ship (AOPS). It talks about why the ships were designed the way they were, and the features that allow them to operate successfully in the Arctic.
These are not icebreakers, they are hybrids, offshore patrol vessels adapted to work in both Arctic and ice free environments. The Danish vessels thanks to the StanFlex mission modules system can fill the role of warships, mounting ASW torpedoes or Evolved Sea Sparrow AAW Missiles.
Norwegian Coast Guard Vessel Svalbard. Photo by Marcusroos
Heated masts, superstructure, antennae, etc. is a really good idea for ships designed to spend much of their time in icing environments. I wonder if the new icebreakers will have this feature?