Paper gathers information on Condition Assessment Programme (CAP), which is implemented by classification societies to thoroughly assess condition of tankers and bulk carriers by inspection of engine and hull. It is voluntary programme, mostly participated by tankers and bulk carriers which are fifteen and more years old and today less present on the market. Special focus will be on ultrasonic measurement of thickness of ship´s plates which is most significant indicator on condition of older vessels. After all measuring is done, data is compared with classification society rules and condition of hull and machinery will be assessed. This kind of inspection provides owners of older ships proof that despite age their ships are equally capable of conducting sea voyage. The authors analyse the number of ship arrivals in the port of Rijeka to gain a better insight into their age. Furthermore, the authors advocate ultrasonic thickness measurement for the purpose of reducing hazards.