If tidal energy extraction is to be maximised then emphasis needs to be placed on the design of the rotor geometry to optimise performance. The work documented in this paper describes the process used in the design and validation of a new blade based on the Wortmann FX63-137 aerofoil. BEMT was used as an initial tool to redesign the blade due to speed in which calculations can be completed. CFD models were produced after to incorporate the hydrodynamics and provide a 3D solution. The performance coefficients for CP and CT were calculated by each of the two computational methods for comparison with the experimental testing. The experimental testing was conducted at the INSEAN tow tank to provide validation for the computational models. The CFD model was found to closely predict the performance coefficients of the turbine at low TSR at and peak power. The BEMT model over predicted both the CP and the CT when compared to the experimental work, however was found to be good as an initial method for redesigning the blade.