MUMS is a software model originally developed for simulation of duels between torpedoes and counter-measures. The model has continously been refined to match further requirements for assessment studies and enhancing modeling measures have been taken to widen it´s functionality and scope towards a more general-purpose under-water combat model. To meet demands for early costeffectiveness assessment of the proposed TMS weapon system (Torpedo-Mine-Sensor) a need has arisen for the possibility of system effect simulations. Thus the MUMS model has been further developed to more adequately describe the planned TMS functionality. This report describes the most significant of the new functionalities which have been added since a previous TMSoriented development.