a note taken from the Ontario Mirror Dinghy Association e-mail network:

"As you have all read in the latest Jibsheet you are now required (in Canada) to carry a buoyant heaving line not less that 15 m. (aprox 50 ft)...  A heaving line must be able to be thrown with some sort of aim, this requires a float with weight.  The weight should not seriously hurt if it hits a person.  You can purchase various items to make it work or Canadian Tire has one at a good price.  You may have to look for it or even ask you local store for it because not all appear to carry it. The heaving line is listed under CTC number 79-0039-4 and retails for $12.99 plus tax.