Glossary Term
Hull Thickness Measurement
Hull thickness measurement is the gauging of metal structure to determine the remaining thickness of plating or structural members and to identify wastage, corrosion loss, or local damage. In yachting, the term is used mainly on steel and aluminium structure, especially where survey, repair planning, or condition trending is involved. The measurements are usually taken by ultrasonic methods and recorded against original scantlings, allowable diminution, or repair criteria.
The term becomes important during class surveys, pre-refit condition assessments, corrosion investigations, and post-damage inspections. Lloyd’s Register states that thickness measurements are fundamental to structural periodical survey compliance, and its survey guidance also notes that suspect areas may require measurement after the surveyor’s overall assessment. That makes the measurement record more than a data sheet; it becomes part of the technical basis for repair extent and survey acceptance.
On a yacht project, thickness results influence whether an area can remain in service, needs coating rehabilitation, or calls for cropping and renewal. They also help define how much metal work is genuinely required, which prevents both under-repair and unnecessary steel replacement.