Indonesia has many maritime potential resources, namely oil and gas as well as renewable energy resources such as wave, current, tidal and ocean thermal. The floating structures play an important role in exploration of the resources. Floating structures like mobile offshore drilling unit (MODU), SPAR, floating storage are important for exploration of oil and gas in deep seas. The trend corresponding to the ocean energy conversion, the floating converter becomes an interesting issue mainly for wave energy conversion because it may be combined with the others renewable energy resources such as solar and wind energies. The challenge is how to design the floating body with highest efficiency wave energy conversion.