In January 2004, Memorial University purchased a stereoscopic Particle Image Velocimetry (PIV) system for making flow measurements. Although the system was potentially very versatile, its primary application was envisioned to be in a towing tank. The system was supplied as a complete package of hardware and software for calibration, data collection and analysis. The intention of the PIV system designers was to collect as many data frames as possible for a fixed measurement plane location, relative to the model. This required the PIV system to be fixed on the towing carriage, moving with the model being studied. It was found during some preliminary experiments that an active seeding delivery system was necessary to ensure sufficiently high seeding particle concentration, especially when measuring flow velocities around a model hull with a large yaw angle. This paper describes the development of a seeding technique for a PIV system that can be used in a towing tank. The paper also includes an estimate of the uncertainty of the measurement system, including the analysis of the flow behind the device used to deliver seed particles into the flow. 水下粒子成像測(cè)速系統(tǒng)(Under Water PIV) Imager SX PIV相機(jī) 用于粒子成像測(cè)速(PIV)的熒光示蹤粒子