Marc-André earlier gave the example of the U.K. legislation, which protects wrecks that resulted not only from conflicts but also just from general service. That's one example where something is protected that might not necessarily have become a wreck as a result of a conflict.
To our knowledge, there is no internationally accepted formal definition of a war grave. That would require, I think, more discussion for the Canadian context to decide what might be included in that definition, whether it's conflict in wartime, whether it's service, and whether it would extend to vessels that were put in service by the forces.