Abstract: A support assembly for use in combination with a boat or like marine craft having an open cockpit or compartment area thereon wherein the support platform is disposed in overlying, covering relation to the open cockpit and is dimensioned, structured and configured to support one or more people thereon in either an upright or reclining position. The material from which the support platform is formed comprises an at least partially flexible, tightly woven polypropylene material which is secured in the aforementioned operative position by anchoring and connection facilities so as to maintain tension on the support platform and thereby provide the support platform with a substantially rigid configuration which will at least minimally yield to the weight of a person's body supported on the support platform over the open cockpit of the boat or marine craft.