I was watching a show recently that stated the US did not engage in convoy strategies for a significant amount of time after U-boats began to attack their shipping. The Canadians meanwhile carried out convoys in the area without losses, and even after the US began the convoy system the Canadians provide a significant amount of support.
So I was wonder, what if, seeing the loss of ressources these attacks on US shipping was inducing on Canada and Britain, the Canadians decided to provide convoys for what American ships they could until the US realised the use of convoys?