in the thesis we demonstrate the derivation of the equations of small-amplitude sea waves (linear wave theory). in the first part, we establish the main differential equation and the boundary conditions, which describe the linear wave theory. we solve the boundary value problem with all the necessary simplifications. in the second part, the equations for the pressure field under a sea wave are derived. we further analyse the behavior of the pressure field and its resulting force in relation to all the relevant parameters: water depth, wave length, and wave height. we represent the dependence of the dynamic pressure to the ratio among pairs of parameters graphically, which enables us to directly quantify the effect of the parameters to the dynamic pressure for a wide range of conditions, which can appear in the natural environment.