Mathematical modeling of floating offshore structures involves dynamical analysis of multiple interwoven and complex interacting hydrodynamic and mechanical systems; the intricacy of this problem is so profound that the behavior of these systems is not "computable" in the sense that we compute, for example, the motions and interactions of celestial bodies. Any attempt to compute analytically the behavior of offshore structures in the presence of fundamentally chaotic excitations arising from naturally-occurring wind, waves and currents is doomed to failure in any truly quantitative sense. This is because the precise environmental inputs are always unknown (and unknowable) and because a comprehensive unified dynamical model of the coupled hydro-mechanical system remains analytically out of reach. While we are quite capable of predicting to one second the time of closest approach of a comet many years in advance of its arrival, in the realm of offshore systems similar precision simply does not currently exist and, due to the chaotic and fundamental complexity of the problem, such precision is not likely to materialize in the foreseeable future.
Given these unfortunate realities, the best we can hope for from available analysis tools, including those offered by SeaSoft, is a qualitative understanding of system dynamics; using sufficient care we can possibly make semi-quantitative statistical estimates of vessel motions and mooring loads that will be of value as one component of a comprehensive design process. No matter how good our tools might appear to be, nature withholds endless quirks and twists which can, and occasionally will, conspire to produce an unsatisfactory and unacceptable result.