Why Canada modified American ship designs

When did Canada last build an American ship design directly from the drawing board?

Even during the Second World War, British and Canadian naval architects modified American designs, partly because measurement conventions differed.

Canadian wartime construction did not simply reproduce American drawings unchanged. British and Canadian naval architects modified the designs before construction. One practical reason given is that American and British measurement conventions differed even when both used Imperial terminology. The example illustrates why an allied design could require adaptation before another country's yards built it.