An improved tarpaulin bow for use primarily on a vehicle trailer in which the bow is selectively movable in a downward direction. The bow is preferably arched and attached to the sidewalls of a typical open-bed trailer. The arched shape enables the trailer to assume a greater load capacity and a multiplicity of the bows support a tarpaulin which protects the contents of the trailer. The bow comprises two sections connected by spring elements. Downward pressure on either section extends the spring elements allowing the bow to move downward without breaking. Once the downward pressure is removed, the spring elements compress and return the bow to its original position and shape.