Abstract: A semi-rigid floating marina adapted for use in both ocean and inland waterways including a submerged structural frame interconnected to a floating surface structure by a plurality of rigid and flexible members. The marina is readily portable in nature to accommodate the changing water level and varying boundaries of inland waterways. A variable buoyancy anchor and an in-situ method of forming the same is provided which allows the anchor to be selectively submerged or buoyed from the bottom of the waterway.