The motion response of a moored open-bottom floating platform is examined by a time-domain simulation technique, derived by the impulse response method that takes into consideration the frequency dependency of the fluid reactive force terms, i.e., added mass and damping force coefficients. The sway and roll responses of the moored platform to random wind loading are evaluated by solving the equations of motion using a simulated random wind loading history. The hydrodynamic coefficients of the open-bottom platform, with pressurized subdivided air chambers having a free air-water interface, are evaluated by modified Frank's close-fit method. Numerical examples of the motion response of the floating platform are presented. The results are used to study the effect of the variation of mooring system elasticity on platform response.