The Determination of Gradients on Enemy-Held Beaches

IN the autumn of 1941, a few officers who were beginning to consider invasion problems realized that knowledge of the gradients of enemy-held beaches was very meagre. Even on the north coast of France, which is com? paratively well charted, information was by no means sufficient for planning an operation which involved the beaching of hundreds of craft in most difficult conditions. No map or chart could possibly set out in detail all the gradients required. Apart from the limitations of scale and the changes which beaches undergo with the passage of time, both maps and charts tend to regard beaches as a kind of "no man's land" with which neither is greatly concerned. This is a general statement. Where large-scale hydrographic surveys of areas which include a beach have been made, the results have been excellent; but such surveys are rare and the areas covered are small. More often the beach is regarded as a border to the sea bed which is being sounded. Work becomes difficult in shoal water, since the boats may ground and may even be swamped if a sea is running; the position of a boat is usually difficult to fix near the water line, owing to the poor condition of the triangles on which the resected positions are based. Add to these difficulties the fact that the common user of charts is more concerned with keeping off the shore than grounding on it, and it becomes clear that charts cannot be expected always to give detailed infor? mation about beaches.