This construction is, however, very difficult to inspect with any high rate of confidence and probability of detection using standard NDE equipment. Many standard methods are point measuring and, therefore, a trade-off exists between coverage and time along with an inability to fully interrogate multiple bondlines beneath the surface. As a result, many boatyards are implementing laser shearography inspection into their build program like that offered by Laser Technology, Inc., in the United States and Laser Testing Instruments, Ltd., in the United Kingdom and Europe. The first stage of hull and superstructure construction is carried out by molding the FRP outer skin into a female mold to form the outer skin. After vacuum bagging and curing, the foam core is cut and shaped to fit, thereby defining the thickness of the structure.
Similar application is made for honeycomb cores.
Finally, the inner FRP skin is applied. At every stage, vacuum bagging and curing are carried out. During lay-up of the FRP in the mold and fitting of the foam core blocks, the construction is susceptible to many of the normal faults that encompass standard composite build. These faults need to be detected and identified to ensure the structural integrity of the boat is maintained. It is, therefore, cost effective to carry out the inspection and repair if faults are present on the hulls during the manufacturing process.