Abstract: The invention is an anchor which constitutes a certain weight in the water, when dropped into the water by means of a connection like a rope or chain connected to the mentioned vessel in order to stabilize the vessels at a required area or point over the sea surface. It has an expandable reservoir which allows the water transmission inside from the outside, keeps the material located inside and is connected to the vessel with the connection and contains a water absorbent material which expands and gets heavy when interacting with water located in the reservoir. When the water absorbent material interacts with water it turns into a mass of thick solid gel and becomes heavier inside the reservoir in which it is located, and reaches the sufficient weight that the reservoir can stabilize the vessel at its place.