1. Tank gauging, level gauging – the process of measuring tank contents.
Every modern chemical tanker must have an accurate and reliable tank gauging system. The system must be capable of measuring the tank contents at any level of filling and must be independent of the high level and overflow control system alarms. The Code specifies three different types of gauging systems dependent upon the flammability and toxicity of the cargo, viz: open gauging, restricted gauging and closed gauging.
2. Thickness measurements which are carried out to evaluate the corrosion wastage of hull structure. Ultrasonic thickness (UT) measurement is applied in the maritime industry. The gauging of a plate or member normally starts out with two readings. If one appears to indicate a suspect condition, then more shots are taken.