Final answer:
Approximately half of all fatalities in canoeing and kayak accidents were due to victims not wearing life jackets. Paddling near the shore is advisable upstream due to slower currents, while the middle of the river may be preferable downstream for a consistent flow and fewer obstacles.
Step-by-step explanation:
According to a study of paddle sport accident statistics from 1995-2000, approximately half of all victims of canoeing and kayak related fatalities were not wearing a personal flotation device (PFD) or life jacket at the time. Wearing a life jacket is an essential safety precaution in paddle sports.
When paddling a canoe upstream, it is wisest to travel as near to the shore as possible because the current is generally slower along the edges of a river due to drag against the riverbank. In contrast, when canoeing downstream, staying near the middle can be best because the flow is more consistent and there's typically less risk of encountering obstacles like rocks or branches near the shore that can cause capsizing.
Additionally, when considering the momentum of canoers in a river, we must take into account both the velocity of the canoe with respect to the water and the flow of the river. The momentum of the canoers with respect to the land would be a vector sum of their momentum with respect to the water and the momentum of the river's current.