Mechanical damage. Computerised monitoring systems are increasingly being used to determine coating performance and the results of these techniques, which are usually in conjunction with larger ships, can be of direct benefit to small ship operators. These surveys reveal the full extent to which various types of mechanical damage are the cause of coating damage. Corrosion is a major problem which can remain unobserved unless intensive monitoring techniques are used. Berthing, fendering and cable chaffing are all actions that can cause mechanical damage. Impact forces on the coating caused by impingement at right angles can cause the coating to fracture and break away from the surface. Erosive forces cause the rubbing of metal along the paint surface, and reduces the paint thickness. Gouging can cause the coating to be cut from the substrate under lateral movement.