An important element in the ComCoast concept is the overtopable sea defence, often a dike.The landward (inner) slope of the dike is adjusted in such a way that it can withstand higher overtopping rates. One of the concepts to improve the resistance is the "Sandy Dike", a cover of the inner slope with layer sand. The sand will be washed away during extreme overtopping events, but this will not threaten the sability of the dike if the thickness of the sand layer is sufficient. The objective of this study is to elaborate the feasibility of the concept by means of a short theoretical study. In this report a describtion of the relation with its environment, a further developed theorie, a provisional design of the concept and a test case are given.