Computational modeling is a valuable complementary tool to assess behavior of bottom trawl fishing gears. A simplified model of the gear that mainly affects to the net is proposed. The model is constrained to steady towing conditions, flat seabed and gear symmetry. Simulations proportionate a number of relevant outcomes like distribution of tensions at the warp, balance of forces at the otterboards or spread under different haul conditions such as depth or towing speed. In this paper we mainly focuss on the description and implementation of the model. Nevertheless, some preliminar comparison with experimental data is also shown.