I suppose it all depends on where you have it docked.
I doubt whether a permit even if you could get one would help showing your 'dinghy' is illegal in most places and a law trumps a permit.
I let people see my dinghy all the time as a matter of fact i just showed it to a group of swedish girls who wanted to ride it.
Yes. Please apply for one at city hall.
canoe be more specific?