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Underwater close visual inspection (CVI) and magnetic particle inspection (MPI) are major components of the commercial diver's job of nondestructive testing and the maintenance of subsea structures. We explored the accuracy of CVI in Experimenta and that of MPI in Experiment 2 and observed high error rates (47% and 24%, respectively). Performance was strongly correlated with embedded figures and visual search tests and was unrelated to length of professional diving experience, formal inspection qualification, or age. Cognitive tests of memory for designs, spatial relations, dotted outlines, and block design failed to correlate with performance. Actual or potential applications of this research include more reliable inspection reporting, increased effectiveness from current inspection techniques, and directions for the refinement of subsea inspection equipment.
INTRODUCTION
Subsea inspection and nondestructive testing (NDT) of offshore structures and pipelines are the most common types of underwater tasks carried out by commercial divers (James, Ratjanm, Chadwin, & Ross, 1985; Leach & Morris, 1988). Indeed, subsea inspection and NDT have taken on such a distinct identity that there exists a formal qualification of "diver-inspector," and subgrades exist even within this category, as specified by the Certification Scheme for Weldment Inspection Personnel (CSWIP). The purpose of underwater NDT is to locate and identify defects in weldment and parent metals of offshore structures by noninvasive mean,. Once this inspection has been achieved, any necessary remedial action can be taken to halt defect propagation. Failure to prevent such propagation can lead to a loss of structural integrity with possible risk to life and the withdrawal of an operator's certificate. Missed defects are attributable to a failure in visual search and carry the most severe consequences for safety (Drury & Forsman, 1996). False alarms or spurious errors are attributable to subsequent decision failures (Drury, 1992).
The initial phase of a subsea inspection campaign involves the close visual inspection (CVI) of welds, in which the diver is required to locate, identify, and report a number of different types of defects that may be present on a weld or its parent metal. Of the various defects that may be found on subsea structures, the more important ones for the diverinspector include cracking, undercutting, corrosion, blowholes, porosity, arc strike, torn surface, grinding marks, slag inclusions, and other defect indicators...