The current trend of weight reduction entails a reduction in safety factors. This approach is understandable, but light profiles are more susceptible. The structure works close to the boundary loads, and their destruction is primarily determined by dynamic relief. Today, composite masts are diagnosed by the following methods: optical microscopy, electron microscopy, X-ray analysis and thermal analysis. These methods are invasive methods. It seems that the vibration analysis of the mast - rigging system could supplement or replace the mentioned methods without the need to dismantle the mast, giving the possibility of testing on the yacht [5]. The article presents the possibility of diagnosing a composite material defect on the example of a interrupts a continuity of structure.