In general, the computational cost required for dynamic simulations of structural problems is very high. In certain situations, the system must provide immediate answers so that important decisions can be made based on them. In other cases, several simulations of the same problem, varying only a few parameters, must be performed. Such contexts are very common in problems involving the dynamic analysis of mooring lines.This work presents a computational system for the dynamic analysis of mooring lines using a time-step adaptivity scheme and a subcycling technique with the objective of improving the precision and efficiency of the simulations. The system is an integrated graphical environment and consists of three modules: preprocessor, analysis, and postprocessor. It also allows interactive-adaptive analysis, in which the user can interrupt the analysis at any time, change parameters and restart the simulation.The methodology used in the development of this system is discussed in detail. The results obtained using the time-step adaptivity and subcycling techniques demonstrate that the computational cost can be substantially reduced by using the proposed methodology when compared to conventional formulations presented in the technical literature.