- A probabilistic model for the collision between a pair of cylinders in tandem subjected to random waves is presented and compared to experimental data. The model is developed by adapting first-passage time formulations from probabilistic mechanics, and is extended to account for a non-Gaussian collision process by applying a Hermite transformation technique. Large-scale experiments were conducted to study the fluid-structure interaction between water waves and a pair of flexible cylinders, designed to represent TLP tendons and risers in approximately 1000m of water. Comparisons between the probabilistic model and the experimental data showed the first-passage formulation for the probability of cylinder collision to be appropriate. The Hermite models provided an accurate-to-conservative bound on the experimental data while the Gaussian model was unconservative. The comparisons also demonstrated the importance of accounting for the non-Gaussian nature of the response for predicting the extreme statistics. 1994.