ABSTRACT Chris Brown†, 2013. Monitoring and Maintenance of Plymouth Breakwater This Breakwater now has four zones of discrete armour: - the submerged foreshore rock slope tidal berm – rock partially covered by 100te precast concrete blocks known as Wavebreakers at a coverage of between 40 and 80% deposited from unique catamaran pontoon an impermeable fitted masonry carapace over the crown of the Breakwater from LWM to LWM on the lee side, rock from LWM to the seabed Concerns have long been raised regarding the stability of both roundheads, the foreshore berm and the 100te Wavebreakers on the berm. Although records of placement of materials exist from 1839 to date, these do not allow accurate estimation of movement to be made. Nor do repetitive cross-sectional surveys, as made between 1840 and 1995, allow any more than a gross approximation of volume change to be made, and then only at discrete sections. Recent developments with GPS, aerial LIDAR and sonar bathymetry have allowed much greater accuracy in o...