Analysis of wave-induced Loads on cross deck of a trimaran ship

Trimaran is a type of multihull vessels that consists of one long slender centre hull with two outriggers or side hulls connected to main hull by a cross structure. However these side hulls have a significant effect on the stability, dynamic behavior, seakeeping performance and wave-induced structural loads. Due to its superior seagoing performance this structure has been of interest to naval architects, especially in commercial and military jobs.Compared to mono-hull ships, a trimaran will be exposed to different structure loads. Because of existence of cross structure, this vessel experience transverse wave loads except for longitudinal wave loads. These loads include transverse bending moments, transverse torsional moments and transverse shear forces that arise from interaction between side hulls and main hull. Furthermore, the fluid load acting on a side hull will transfer to the main hull by cross structure. In this article hydrodynamic loads of cross deck of trimaran was calculated using a 3D panel method based on the linear potential flow theory in the frequency domain using Maestro software. The results showed that in beam seas the responses are not sensitive to changes in the vessel speeds and only depended on wave frequencies. Moreover peak magnitudes accrueat the vessel speed of 25 knots in the Bow Quartering Seas (135 degree).