A linear, frequency-domain, performance model is presented that links an oscillating structure to air-pressure fluctuations with a Wells Turbine in 3-dimensions for a floating OWC device. An array of field points defining the interior free surface allows hydrodynamic parameters relating to the fluctuating air-pressure within the OWC to be calculated using reciprocity relations after analysis with a potential flow solver. Device structural parameters for a non-optimized BBDB are detailed and the performance model is exercised on this device. The hydrodynamically coupled resonance location of the OWC is identified. Power values for two optimization cases are presented. The first optimization case considers only the power absorbed by the fluctuating air-pressure, while the second case considers the power absorbed by both the oscillating structure and the fluctuating air-pressure. In both cases the optimal resistive damping and the resulting performance are presented. Comparison of these two optimizations shows a 30% increase in power conversion in monochromatic waves when both the oscillating structure and the fluctuating air-pressure are considered in the optimization procedure.