It is very common to use stern trim control devices in order to improve hydrodynamic performance of high speed vessels. Effect of stern trim control devices (wedges, trim tabas, interceptors) was analysed on the basis of dozens of tested projects of semi-displacement and planing hulls. Projects were tested in the large towing tank (276 m × 12.5 m × 6 m) which enabled that fairly large ship models were manufactured. Corresponding Reynolds numbers in model scale were larger than 1 × 10⁷ for the majority of conducted tests. Focus of the research was oriented towards higher speeds, i.e. especially limiting speeds where it is considered that impact is no longer positive. Resistance force and changes in dynamic trim angle were monitored and described. Influence of the characteristics of the hull (ratio of main dimensions, LCG position, deadrise) was observed and commented. On the basis of conducted analyses guidelines are created with the intention to serve as simple practical tool in early design phases for quantitative evaluation of possible gains.