What is the length and construction of the canoe in question? Does it have cross members?

-Make sure your roof rack bars are spaced apart as far as possible, this will give you the most stable platform. I usually center the canoe on the roof rack, except for long trips.

-Use 4 straps: 2 over the top at the front and rear of the roof rack, these hold the canoe down. The other 2 connecting the front/back of the canoe to front/back of the vehicle. For the rear connection point I like to loop the strap around a hitch pin. The reason I asked about canoe members is they are usually what you’ll need to connect to in order to attain the rearward pull. The front you may need to get creative if you don’t have an aftermarket bumper/recovery points. Put towels between the strap and paint to prevent damage.

I’ve portaged my canoe thousands of times using the above method, albeit not on my 4R.