The most reliable floating structure for the unexpected storm conditions of east coast India deepwater is presented in this paper. Dry-tree support due to very low heave response in 100 yrs return strom attracted this vessel solution to be cost effective in ultra deepwater. Several advantages are inbuilt including self installation of the vessel. The key design features that would enhance the applications of the semi-submersible design for deepwater are vessel motion characteristics, heave natural period, high air-gap, large deck-area, large deck pay-load, reduced mooring load, large riser pull-down load, feasibility for dynamic positioning, self-installation, quay-side top side integration and float-over installation. This paper presents the design of dry-tree support semisubmersible for drilling and production from deepwater of east coast India. The displacement of the vessel is 82500T, payload is 15000T, free board is 19.85m and the keel tank size is 91.5m by 91.5m by 6.1m. The ballast in the keel tank is 28000T.The hydrodynamic response of the vessel obtained by the experimental study for the retracted condition is used to validate the numerical results. The numerical study on the dry-tree submersible with keel tank in retracted (draft=39.62m) and telescopic condition (draft=65.25m) is carried out and the results are used to demonstrate the application of dry-tree support semi submersible for deep waters of east coast of India.