I've used an arborist throw weight, but have never taken it canoeing. I made a slingshot for mine which can get the weight up to about 70' with good accuracy. I've probably put that weight into trees a hundred times and it's never gotten stuck. About the only thing I use it for anymore is to annually place a holiday decoration as high into a tree as possible.
Before I had a throw weight I used a fishing rod with monofilament and a 1oz weight. That worked okay. Problems were accuracy of cast, difficulty seeing the line in the trees, and the weight/line would sometimes wrap around a branch. With the mono over a branch, I'd lower the weight to the ground and attach a heavier line. Many canoeists carry fishing gear, so this approach might work for them.
I've always used a stick or rock or water bottle tied to the end of the rope as the throw weight for hanging my camping food. The water bottle, bane of environmentalists everywhere, deserves special mention. Advantages are the plastic bottles are inherently slippery and of a size and weight that doesn't easily hang up in branches. The weight can be adjusted by changing the volume of water in the bottle. On the carry, the weight can be lowered to near zero by emptying the water.
Regarding food hangs, here's a story I imagine I've posted before:
On a trip to Shoeshone Lake, I was told to string my vittles up from cross-poles I would find at the site. The cross pole was attached to two vertical trees with chain, and the darn thing was 20 - 25 feet up. I wasn't sure I had enough rope to get over that bar and back down.
I tied together the several lengths of rope I had, tied a hefty stick on one end of the line, and about threw my shoulder out pitching the stick over the cross bar. As the stick was sailing over the bar, it occurred to me I better grab the loose end of the rope before the stick carried the whole rope over the bar. That was a good idea, but in the excitement I kind of lost track of the physics of the situation. I caught the loose end of the rope, which arrested the flight of the stick, which became the weight on the end of a pendulum. After I caught the rope, I turned back toward the bar and the stick swinging towards me on the rope smacked me across the jaw. I don't know whether the shock or the pain was greater.
I was quite afraid of meeting a bear. There wasn't a lot of human traffic and the rangers had really hyped the danger of bear encounters. Nobody was at the three other sites I visited while wandering. If there was a bear encounter, it would just be me and the bear. I swore so loud after that stick hit my face that any bear in the neighborhood would have been more scared than me!
