Estudo experimental da velocidade de avanço e das ondas geradas por uma embarcação regional do tipo rabeta

Abstract

The use of small boats, which can reach high speeds, is common in the Amazon region. Therefore, safe, and sustainable navigation activities with this type of vessel still require studies that allow to characterize their hydrodynamic behavior. This work aims to study the speed of advance and the wave patterns generated by a common regional vessel in the State of Amazonas, known as a rabeta, frequently used for short-distance transportation between riverine communities. First, surveys were carried out in the field to document some examples of these types of vessels. Then, a real-scale experiment was carried out by selecting a representative vessel as a study case, aiming to determine the forward speed with maximum engine power. To measure speed, we used a cell phone GPS application and image processing techniques applied to videos obtained by a drone. With this last, the wave patterns generated in the water by the boat were captured. In addition to the experimental study of speed, a slender body hydrodynamic method was implemented to represent the experimentally captured wave patterns. The results obtained demonstrate that the boat can achieve modes of operation defined by a length Froude number around 0.5. Likewise, it is defined that this type of vessel can reach high speeds, mainly in the semi-displacement operation regime. Furthermore, the results obtained with the drone demonstrate that the use of these types of vessels can also generate wave trains that interact with the sand banks or vegetation next to the boat path. Similar studies can be implemented to understand the typical modes of operation of various regional vessels.