During process of water-exit

the slender body will suffer a very complex loads environment which may be consisted of wind

waves

as well as currents

which will cause transverse vibration under these loads. Lowfrequency vibration is characterized by huge vibration energy

large structure displacement and big deformation

in addition to the slender structure of the slender body

it is quite necessary to identify and check strength transverse low frequency vibration loads the maximum section

that is dangerous transversal. Based on velocities information measured by sensors and the modal superposition method

a load identification method is developed for transverse low-frequency vibration. A modal with theoretical solution is used to verify the method

and results show good agreement with the theoretical solutions.