Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2009. / In this thesis the mathematical modelling and simulation of an autonomous underwater vehicle is presented. A generic six degree of freedom model suitable for AUV control applications is presented. This model is then tailored to the AUV testbed developed by IMT. The model parameters are determined from vehicle geometry alone. In addition to this, a linear model is presented and analysed in order to determine the modes of motion for AUV. The development of a generic visualisation system suitable for underwater vehicle simulations is also presented. A generic MATLAB based AUV simulation system is developed, and used to supply the visualisation system with the necessary simulation data. Lastly, two example simulations are shown