Flying an ensign on a boat

[Tim Rabbit]

I know the tradition of flying the red ensign from a private boat in the UK. When I hire a pleasure craft in Belgium can I fly a red ensign on this craft?

[heathfield]

(From the 1894 Merchant Shipping Act). "The Red Ensign usually worn by the merchant ships, without any defacement or modification whatever, is hereby declared to be the proper national colours for all ships or boats belonging to any British Subject. ( My italics).
My interpretation is that if the boat doesn't belong to a British Subject, then the use of the Red Ensign would be 'improper'