AIUI, the Canadians were not buying the three BBs for their own use, as Canada barely had the political will to keep its two ancient cruisers in service, three BBs and presumably support ships are out of the question. Instead, they were planning to pay for the three ships for the Royal Navy to help it defend the Empire, including Canada, so Canada wouldn't have to keep up its own navy besides maybe some fishery protection vessels. The other problem here is during WWI, the British government did not allow any new capital ships to be built. Fisher got some of his personal projects through on technicalities, but three more QE's are not getting laid down and completed during WWI.
Most of the ships Canada had were severely outdated. Maintaining the was well already hard.
There was concerns about German sabotage however to my knowledge, it was never strictly about a Central Powers ship infiltrating Halifax. Even if something like that would have happened, the date of the Halifax Explosion really is too late for Canada to get something like capital ships. If Canada somehow wants capital ships, it is going to need to get them before WWI kicks off similarly to Australia. Any capital ship procurement that starts during WWI or leaks into the interwar period is going to see the nation running afoul of the Washington Naval Treaty. Canada doesn't have the political willpower or the naval development to operate any real number of capital ships, the Navy was underfunded to the point of nearly dissolving constantly throughout its early periods. This is why Canada was flat out giving the UK government money so they could build capital ships, Canada couldn't do anything with them itself. Canada's shipbuilding industry is also completely unsuited to building even small warships to the point where if you wanted to build capital ships in Canada, you'd need a good decade of heavily government sponsored development and/or major pieces like guns, fire control systems, machinery, armor plates, etc to be brought over to Canada wholesale.
But not as difficult/expensive as three 30,000+ ton battleships, each of which has probably twice the crew of the two cruisers combined and needs major facilities to be kept up to work on them.
If a CP ship got across the Atlantic somehow and caused the explosion, it is most likely to be a sub (not really the niche of a BB to counter) or an AMC (much cheaper to counter with a cruiser) slipping a team of saboteurs ashore somehow. BBs aren't really justified by either and as I said in my previous post, would probably not get built anyways.
They probably can't be kept by Canada (or Britain) as additions to the RN capital ship allowance under TTL Washington Naval
Don't give up...work the problem.
I would question why? I think just a larger or changed WNT allowance?
Having 3 more QEs changes the WNT!
I dont see any Canadian QE not being finished (or scraped) mid-war? Ie by WNT they would be in fleet service of Canada or RN? Maybe at the cost of R&R or Hood, but that makes for even less change?
The proposed funding for the three "Dreadnoughts of the latest type," came in the Naval Aid Bill of 1912. There was a perceived emergency at the time that the Royal Navy was short on capital ships.
The battleships were killed by internal political strife and indecision in the Canadian government. The best POD is to have some kind of political champion to force the appropriation bill through Parliament in 1912-13, or to have an international crisis that causes this issue to take priority in the Canadian political mind. You could invent a character to midwife the battleship project, or take a historical figure and buff them up. You could create an international incident from whole cloth, or you could amplify an existing one. You need not even amplify the events of an OTL international incident, only the perception among Canadian Parliamentarians.
