NDE of historic structures - USS Constitution

The USS Constitution is the oldest flowing commissioned ship in the US Navy. Recently, the USDA Forest Service, Forest Products Laboratory, was involved in developing an inspection methodology for the use of Navy personnel responsible for maintaining the ship. Several NDE techniques were used to assess the condition of fasteners in the ship and the general condition of the wood comprising it. Radiography and ultrasonic techniques were used to assess the condition of the copper pins used as fasteners. Stress wave NDE techniques were used to locate areas of degradation in the wood. This paper describes the stress wave techniques employed and results obtained form their use.