Alternative drive solutions are one of the key technologies for future mobility concepts. Hydrogen-powered fuel cells have significant advantages compared to battery-based drive solutions, e.g. long range and short refuelling times. On the other hand, there are disadvantages regarding the costs of the vehicle components, such as the type IV pressure vessels for hydrogen storage, which are loaded with up to 700 bar. Defects introduced by the wet filament winding process, such as gaps and overlaps between neighbouring fibrebands, can lead to a reduction of the original strength by up to 20 % [1]. For this reason, pressure vessels are frequently overdimensioned to meet the required load capacity, which results in avoidable costs. [1] Vasiliev, V. V.: Composite pressure vessels: Analysis, design and manufacturing. Blacksburg, USA: Bull Ridge Corporation, 2009, ISBN: 097-0-9787223-2-6 The publication presents studies on the influence of the curing process on the extent of defects in the laminate, such as gaps and overlaps between neighbouring fibrebands as well as variations in the fibre volume content, and the effect of these defects on the mechanical properties of the pressure vessel. Such defects are introduced into pipe-shaped samples in various degrees of severity. During winding, the fibreband tension and the position of the defect in the laminate are also varied in order to investigate the influence of these parameters on the occurrence of defects and the mechanical properties of the laminate. Ring-shaped test specimens are taken from the pipes and subjected to microscopic examination and mechanical testing using the split-disc method. Based on these results, it will be discussed which defect dimensions are acceptable or critical in the production of type-IV pressure vessels and how these defects can be detected during the process.