This paper presents results from the third phase of large scale mooring investigation at the Scapa Flow in Orkney, Scotland, for wave energy applications. It considers the suitability of three slack mooring line configurations, namely, i) compliant chain, ii) complaint hybrid and iii) taut fibre rope arrangement. This investigation is extended with a numerical study analysing the station keeping criteria for the three slack line configurations and that of a taut system for wave energy converter installations. The results are used to discuss the suitability of the individual mooring line configurations and that of the taut arrangement. This paper is partially to provoke a discussion on the advantages of a taut mooring system and raise the issues that need to be solved if they are to be practicable.