Abstract: This paper presents an initial quantitative analysis of the extent to which networking multiple-monostatic active sonar systems can improve performance in detecting submarines. The improvement mechanism explored is the sharing of data on detections, with tracking being performed centrally. Our analysis indicates the conditions under which the improvement should be present and provides an estimate of its magnitude. This is achieved by focusing on the step of centralised track initiation, using sonar coverage area as the metric. We identify situations where coverage area at the 95% level can be more than a factor of 10 larger with centralised tracking compared with tracking by individual sonars. This is achieved solely by sharing detections, without any other modifications to the submarine kill chain. The results show that a 30% detection probability (Pd) can be tactically useful provided that there are other sonars with a similar Pd for the target of interest that share information on detections. This result may provide a prac¬tical way around the great and continuing difficulty of obtaining acceptably high Pd values at tactically significant range from a single sonar.