in this study an analysis concerning the pulsating and impact portion of the tensile stresses inside tetrapod armour units is presented. The data has been obtained from a series of small scale model tests performed at Delft Hydraulics. Stresses have been measured using a load cell technique developed and made available by Coastal Engineering Research Centre in association with Aalborg University. For the rested area of the breakwater the following parameters only appeared to have influence on the stress distribution inside a leg of a tetrapod: (1) significant wave height; (2) water depth in front of the breakwater. Other parameters investigated which appeared to have no or negligible influence on the stress distributions were: (1) the fictitious wave steepness; (2) the location of the tetrapod; (3) the orientation of the instrumented leg of the tetrapod