This is a very interesting question of international law.
Your vessel is considered to be part of the jurisdiction where it is registered; so when you are on your boat you are residing in that jurisdiction.
under marine law you operate under the regulations of that registry, But you must also comply with the laws of the country you enter.....
.....so who's law takes precedence, the country of registration or the country where you are visiting?
Here's my little scooter onboard my cat:
When it's onboard is it in the UK jurisdiction even if I'm in Spain?
When I take onto the road is it only in Spain for that period of time, and does it return back into uk jurisdiction when I load it back onboard?