There is another reason you can't do the Capilano River, even if you have a small enough boat.
The lower section of river is the private property of the Capilano reserve. I did motor up the river last year, and made it to where it is not navigable. The natives promptly came out and told me I was trespassing.
They followed me on shore all the way out to make sure I complied.
I enquired further later. Apparently with the Lions Gate bridge was being constructed, they moved the river several hundred yards on to the reserve....so apparently it is legal. The native that followed me out however, told me their claim goes out to the bell buoy that is well into the salt chuck....that I don't buy.