Davie built all of Canada's existing destroyers. The frigates were built half by Davie and half by Saint John shipyard. Of course Davie could build destroyers. It's what's it's been doing for the past 190 years.
In terms of the submarines, I'm sure we could have a debate about this all day, but I would honestly say that I don't think they should be built in Canada. It doesn't make any sense. You could build any ship in Canada. Could you build submarines here? You could, but it would take some expertise. If you look at what the Australians are doing, it's quite interesting, I think.