I think there's three parts to the question:
1. Will it work?
2. Will it be legal?
3. If No.1 is yes but No.2 is no, will you get found out?
I've had a look at Humminbird's website, and you can download the manual to the VHF5 Marine Radio (I assume this is the one you're considering)
It has US and international channels (but strangely not Canadian), so I guess that the answer to part one of the question is yes
There is, however, no mention of type approval, either FCC (US) or CE (European) so it looks as if the unit won't be type approved for the UK or Europe
But as to whether you'll get found out and thrown in prison (or put into Dave Mallett's stocks)... who knows?