In recent years, with the development of CAD and CAM technology, the boar design and boat component manufacturing processes have been greatly improved. However, the quality of the boatbuilding still mainly relies on the boat assembly process and tools. The accurate measurement of the angles between the boat keel, bulkheads and frames is a bottleneck problem in small boatyards. This paper investigates the current techniques used for angle measurement in civil engineering and geographic survey. The main problem with the application of these angle measurement techniques for boatbuilding is that sensors currently available on the market have relatively low accuracy, high price and are used in strict work conditions. Based on the investigation and analysis, a novel principle of angle measurements for 3D construction is presented. The system consists of a laser diode, photodiodes, targets and a microprocessor. The laser diode sends a laser beam to targets, where the photodiode captures the reflected light to produce a signal. Using the signals, the microprocessor calculates the measured angle with the accuracy level of are second. The system is of high accuracy, low cost and reliable to be used in boatyards.
