This paper presents an initial study of the mechanical characteristics of some deepwater floater designs for offshore wind turbines. Three different concepts (NREL TLP, Dutch Trifloater, and Japanese SPAR) are summarized, based on data from the available studies. A 5 MW Horizontal Axis Wind Turbine is used for the reference wind turbine and the steady wind load is calculated from the Blade Element Momentum method. These three concepts are simplified to 2D models and the static analyses of NREL TLP and Dutch Trifloater are compared. The 2D NREL TLP model is selected for dynamic analysis, in which: (1) regular and irregular wave loads are calculated from the Morison equation for the relative motions in the time domain; (2) Airy's linear wave theory is applied to compute the wave kinematics; (3) The 10-minutes irregular waves are realized from the JONSWAP spectrum. For comparison, the same 2D NREL TLP floater model is also developed and implemented as a subsystem in the wind turbine simulation program, HAWC. The HAWC results are compared with those from the author's model. After static and dynamic analysis, the irregular wave calculation showed that the fundamental eigenfrequency of the wind turbine is the main reason for the severe resonance. The latter NREL TLP 5 MW wind turbine model improves the situation, but its eigenfrequency is still in the range of the main wave frequencies. At 9 m/s wind speed and in a regular wave of 10 m wave amplitude and 12 s wave period, the shear forces and the turning moment for the floating wind turbine increases 100 times more than for onshore installation. The output power would oscillate between 1 MW to 4 MW because of the relative velocity between wind turbine and the wind, from 7 m/s to 11 m/s. Therefore, control or damping of such large power fluctuation caused by the movement from the waves is a major task for further study.