Measuring Propeller Pitch Based on Photogrammetry and Computer-aided Design

There are a number of methods for measuring propeller pitch, but there could still be problems for many fishing boat builders because of their lack of necessary professional equipment. This paper presents a method of propeller pitch measuring based on photogrammetry and CAD (Computer-Aided Design). This method consists of three stages. The first stage is to take a series of 2D image photographs of the propeller using a smart phone. The second stage consists of processing these 2D images using photogrammetry software to create a 3D virtual model of the propeller. A CAD program is used to measure the pitch at different radii of each blade of the 3D virtual model in the third stage. In this study, several propellers for fishing boats were measured and the results were compared to those archived by using an EDM (Electrical Discharge Machining) machine and by a qualified professional worker using simple tools. The measurement results showed that the proposed method would be acceptable for measuring pitches of propellers of fishing boats.