Simplified finite element modeling of a stiffened cylinder subjected to underwater explosion was investigated. The use of smearing the stiffeners into the base structure as well as beam modeling using SOR (Surface of Revolution) beam elements were used in the simplification process. The dynamic response and overall global deformation were then compared between the fully discretized stiffened cylinder model and simplified models. The study first examined the effectiveness of smearing stiffeners into a flat plate. The smearing of stiffeners into a cylindrical shell orthotropically was then examined. Next, beam modeling of both unstiffened and stiffened cylinders was investigated. Finally, an integrated beam/shell model of a stiffened cylinder was developed. These models were subjected to the same underwater explosive loading for numerical study. The analysis showed that when comparing the dynamic responses caused by underwater explosions between the discrete model, the beam model, and the beam/shell model of a stiffened or unstiffened cylinder, globally similar results could be produced.