Ships under the regulations , it is necessary to measure the rudder clearances and the tail-end shaft wear down clearance measurements in order to ensure that they are seaworthy and safe for the cargo and the crew that mans it.
Underwater ultrasonic thickness is a widespread technique, which allows you to measure the thickness of different materials, without requiring access to both sides of the material, such as classic measurement methods
Classification societies at particular intervals inspect and certify to the relevant authorities, how the ship complies with the conditions of the license and that it can sail safely in accordance with all international conventions.
