The ClampOn DSP Subsea Corrosion-Erosion Monitor (CEM) continually monitors and quantifies changes in wall thickness over a large area of a pipeline. The instrument estimates the rate at which corrosion and/or erosion reduces the thickness of the pipe wall. In this way, it can provide operators with an early warning of potentially catastrophic failures before they occur. The CEM is therefore also an effective tool in helping operators comply with newer regulations regarding the need for condition monitoring. It can be retrofitted to existing structures or installed on new pipelines before they are deployed subsea.