A method of evaluating wave pressures that may be expected in a given locality is presented in this paper and the writer applies the results of his observations to the investigation of structural stability, or design, of seawalls and breakwaters. Since all factors contributing to the solution of the problems herein considered are only approximately knowable, no theoretical approach was deemed advisable. However, all available observational data were used in evolving a method of analysis. Engineering structures should be designed with a certain margin of safety, yet not wastefully. In the past many structures, as first designed and built, required rebuilding after each severe storm until a satisfactory structure was finally developed. The design method herein presented should enable one to appraise his problem within reasonable limits, and arrive ·at a fairly economic solution, according well with experience on existing structures of enduring stability. The concluding remarks and two illustrative problems substantiate this claim. Certain data on wind velocities are included because of the labor involved in collecting this information which is not readily obtainable from the United States Weather Bureau records. Data on weights of cribs and on coefficients of friction, so essential and important in design and stability investigations, are given because the elements of judgment and experience enter largely into their choice. The meager textbook information available may not even be applicable, or it may be misleading.