Some cable-driven parallel robots (CDPRs) can be rapidly deployed on-site. To achieve such deployability, the fixed frame is usually substituted by four masts. However, not having any rigid fixture between the masts reduces the overall stiffness of the CDPR. This paper introduces a CDPR called Rocaspect, that has four compliant masts. The robot behavior and accuracy is evaluated experimentally and three different mast models are proposed.