A new design for mooring tidal stream turbines is proposed and its feasibility is studied by analysis and scaled model tests. The design features mooring multiple turbines on a common tether with anchoring only at two ends. The whole array of turbines is in submerged floating with only two major lifting buoys partially above water surface. A new method to moor a single turbine on the common tether was devised and tested using models. The mooring system can prevent the single turbine from rolling and also allow bi-directional operation by a vertical flipping motion. An end clump system was also designed to work with the new turbine mooring method and the lifting buoys to maintain the turbines within desired depth range in varying operating flow speeds. Analysis in mechanics provided example designs and corresponding parameters. Scaled model tests demonstrated the feasibility of the single turbine mooring method and the end clump depth maintaining approach.