Its ok for a submarine to sail through Canadian water, innocent passage and all that...
Actually, Underway, there is no such right of innocent passage in the NWP according to Canada's official position.
Canada drew straight lines across all the outside edges of the Arctic archipelago and claims the waters so enclosed as
internal waters of Canada. There is no right of innocent passage in internal waters. In international law, the state has absolute and unrestricted power over such waters. This position is based on what is, IMHO, a fallacy, that the ice in those passages is used by the Inuit
as if it was land to hunt, fish and travel.
I say it is a fallacy because, obviously, it only applies when there is solid ice across the whole area, i.e. in winter. In summer, when the waters are open, the Inuit use boats like everyone else. In winter, there is just no ship traffic up there, other than icebreakers on extremely rare occasions (last time CCGS Amundsen overwintered there, it did so stopped, as a floating base rather than icebreaking), and the ice reforms quickly behind them.
The US position is that the 12 NM waters from each island in the archipelago are properly
territorial waters of Canada, and up to 200 NM, are Canada's EEZ, but the NWP itself is an
international strait. In such waters, international law provides for the right of innocent passage, and in international strait, there are even more restrictions on what the nation whose waters it is can impose. The US position, BTW (12NM territorial, and 200 NM EEZ), mean that the NWP cannot be transited without, at some points (in fact multiple and over quite a wide area), being forced to enter Canadian territorial waters, and that the whole of the archipelago is unambiguously Canadian EEZ.
I also believe that the US position is wrong. The US position on the 12 NM territorial waters and 200 NM EEZ is the correct starting point, but there are still numerous bays and fiords in the Archipelago that meet the criteria of international law for enclosure with strait base lines to become internal waters, and these would have to be promulgated by Canada everywhere they are applicable, IMO, and then the 12/200 NM calculated therefrom. Also, I don't believe that the NWP meets the criteria for designation as an international strait because it simply has never been used for international navigation. There have been very very limited attempts, such as the SS Manhattan, of exploring such possibility, but it came to no fruition, and "adventurers" transiting for the sake of the adventure, but it is not and has never been used for "international navigation" as this term is employed in International law of the sea.
Personally, however, I think that the actual properly applicable regime should be adopted sooner rather than later by Canada and Canadian legal framework that would be workable when the waters become more accessible should be put in place as early as possible.
P.S. Little known fact: As the Arctic ice recedes more and more in the summers, there is a lot more first year ice and some multi-year bergs that break and float around, The archipelago, with its configuration and weird currents actually catches more and more of this ice, leading to more frequent, not less frequent, number of events where the NWP gets blocked by ice at various choke points in the summer. That is making navigating the passage more difficult and uncertain for navigation - not the other way around.