Why are low head dams dangerous to small boats?

Low head dams are dangerous to small boats because they create strong, unpredictable currents that can capsize or trap vessels. When water flows over the dam, it creates a recirculating hydraulic effect, pulling boats back towards the dam and making escape difficult. This phenomenon, often referred to as a "drowning machine," can lead to serious accidents and fatalities, especially for those who are not aware of the risks. Additionally, the relatively low height of these dams can make them less visible, increasing the likelihood of collisions.