In this paper, a new method is proposed to find a point scatterer's height in a 3-D marine scene with a monostatic lowgrazing angle coastal radar thanks to multipath propagation. A simulator is developed to predict electromagnetic scattering of a 3-D marine scene. Our work is twofold. Firstly, a marine scene is simulated with a three-dimensional linear sea-surface model. The scattering model used is the GIT model based on an experimental campaign measurement with low grazing angle. Multiple-bounce is included with the Four Path Model (FPM). Multipath effects for low grazing angle in the ocean environment are investigated with an isotropic non dispersive reflector above the sea surface. Secondly, a review of height finding algorithms is realized.