Canada has three types of firearms licenses.
Longguns are basically firearms, provided they are semi-automatic. You could buy an M4 semi and it would be treated like an unrestricted firearm, provided it is incapable of going to fully automatic.
Pistols are restricted, which is a different license, but anyone can take the course and get the ability to own one.
Carry permits are usually job related for any class, otherwise it must be in a locked box in the trunk with the ammunition in a seperate locked box with a different lock. Job related carry permits (armoured car, police, military, etc. are permitted based on the job duty)
Prohibited is automatic and assault weapons capable of firing full automatic. These are restricted to police and military, carry permit is the same as above.
Hope this clears that up. Maritime law is different than on land. At sea, you are basically piloting your own small country on your vessel, and what happens on your vessel save for a crime like murder, torture, or rape, the laws are no longer enforceable. Carrying a pistol on your vessel is not a crime, even without an open carry permit (concealed is usually prohibited).
So if you have a prohibited assault rifle on your vessel in Canada but do not take it onto land, you are in the clear. The moment it is on the dock, provincial and Canadian criminal code applies to it’s transport. Common sense would dictate that if you do not have the necessary permits, you couldn’t have transported it to the boat in the first place, so this sort of thing is exceedingly rare.
Canada actually has more guns per capita than the United States (albeit with a much smaller population).
Hope this clears up the gun thing.
I made this post because I have been encountering bandit A-hole tug operators (not hauling logs, but boats) for a few years now who are doing their best to create make work projects for themselves in the off season, which includes stealing boats - most importantly to me, my boat.