Wikipedia
Escalpelamento
Scalping is the eradication of the scalp from the skull, in most cases because of boat motors. Scalping is a widespread problem in the Amazon region, where this type of accident is common, because of the poor safety conditions of the typical boats used to travel and to work throughout the Amazon River, called Voadoras.
Usual victims of these accidents in the Amazon are the ribeirinhos, rural people who live along the river and run on small boats to work and to get the city.
A protection for the voadoras engine was designed and produced, in order to prevent these accidents, but a lot of ribeirinhos still don’t use them.