Summary The St. Lawrence Seaway Development Corporation in the U.S.A. has been assigned with the task of demonstrating the feasibility of winter navigation on the St. Lawrence River. As a part of this program, an ice boom was designed, installed, and instrumented at Copeland Cut in the Wiley-Donden Canal near Massena, New York. In order to measure forces exerted on the boom elements by the ice cover, twenty tension transducers were designed, built and located in the critical members of the boom. Force measurements were made before, during, and after ship transits through the ice cover and boom opening. Typical signal recording of several of the tension transducers are presented.