A rigid harness for a floating aquatic structure (1) is provided. The harness (2) comprises first and second ends, and the first end is pivotably attachable to the structure (1) such that in use the harness (2) may pivot about a single pivot axis (23) through a range of angles relative to, and including, the vertical. The harness (2) further comprises one or more mechanical and/or umbilical connections (28,30,32) adjacent the second end thereof. A mooring system for a floating aquatic structure which incorporates the harness is also provided.