Studies on the efficiency of purse seines were carried out in a water circulating experimental tank in a static water condition using five simplified seine models of different hang-in ratios. The results indicate that the seine with hang-in ratio of 34% sank the fastest and seines with 25% and 30% of hang-in ratios had sinking speeds nearly equal to each other. The final depth of the former seine wall was 91% of the designed seine depth, while that for the later was 97% and 100%. From this data it is thought that a net with about a 30% hang-in ratio is the most efficient for both fishing and also in terms of construction. Model experiments on the two net designs of mackerel purse seines operating in Indonesian waters revealed high sinking speed those are 53% and 40% of setting time, after that time both model nets decreased the sinking speed. So it is recommended to commence pursing because at this moment, the stretched seine wall of model net A showed 72% and model net B showed 86% of seine depth. The effects of various pursing speeds and pursing times on the purseline tension of two model nets A and B showed a quadratic function. The purseline tension of model net A was greater value than that of model net B, the reason might be caused by the different design and size of the seine used in the experiment. The relationship between pursing speed and the value of square root of the opening area of seine bottom by initial opening area of seine bottom was a linear function. The opening area of the seine bottom of model net B was faster closing than for model net A, even though the purseline length of model net B was longer than of model net A.