Abstract: A cooler assembly for particular use in combination with catamarans is set forth comprising a support base defined as a container formed with planar sides and a planar floor overlying an arcuate bottom surface of a complementary configuration to a convex arcuate upper surface of a pontoon of an associated catamaran. The container includes a plurality of clips secured to each side of the container to secure the container to downwardly directed flanges of the catamarans pontoon. A flexible strap is pivotally mounted at one end to a right side of the container and formed with a forward terminal end including a rigid "U" shaped clip for reception within a slot formed within a left wall of the container to secure an associated refrigerant cooler within the confines of the container.