Nice work.
hm. at first glanze I feel the black lines (shape of hull), at bow (under and above water line) feels a bit rough. The same at rear just above the water line. There are also an section of black line in the underwater hull where the propeller shaft meet the hull (flank propeller) it looks like several lines that have been connected to each other. And should those line be black, are they at 90 degree angle toward the rest of the hull, since ice breaker have an smooth hull...
Other than that, you still got it.
BTW. Have you tried to color those water intake for the reactor (powerplant) in very dark red instead of black, Break the rule a little!
Just noticed it. the bow knife as you have drawn it now, it's looks like it's just an metal plate mounted on the hull, in fact those knife are smooth with the hull, so an outlining toward the hull should be black or dark red.
Bow of ship with similar bow. notice how the knife is smooth with the hull: