In the current paper, we have developed a method, based on 2D+T theory, to model the performance of doubled-stepped planing hulls in asymmetric conditions. We have performed Computational Fluid Dynamics (CFD) simulations to evaluate the difference between the results of the 2D+T method and CFD. We have validated 2D+T and CFD simulations. The quantitative comparison between the results of both methods shows they predict almost similar heeling moment, resistance and trim angle for a doubled-stepped planing hull. Results of non-stepped and doubled-stepped planing hulls are compared against each other, demonstrating that an increase in heel angle has less influence on the performance of the doubled-stepped planing hull. The heeling moment of a double-stepped planing hull is found to be smaller than a heeling moment of a non-stepped planing hull at early planing speeds, but, by the increase in speed, heeling moment of doubled-stepped planing hulls becomes slightly larger.