To evaluate the performance of proposed submerged intakes in an early design phase, a performance analysis model able to evaluate a range of intake geometries is required. This document details how such a model was developed with the use of available sub-models for specific flow features. A formulation of the method of characteristics suitable for rotational  flow was used to compute the parts of the flow field not affected by viscous effects. Boundary layers, both laminar and turbulent, were implemented via integral integral relations that provide the growth of the boundary layer. The effects of shock waves interacting with the boundary layers, both in shock wave reflection on the intake walls and the pressure rise in the shock train, are implemented via experimentally obtained correlations. To investigate the effects that several design variables have on the intake performance, a parametric study was performed with the intake analysis model. It confirmed the initial expectation that an increased expansion angle significantly decreases the total pressure recovery, a measure of efficiency, that is achieved by the intake. Using a gradual compression or multishock compression surface reduces the loss of total pressure due to shock waves. Performance could be further improved by performing further internal contraction via an improved cowl shape.