In this paper, discussion is made on a problem of determining the inspection interval appropriately to keep the reliability of ship structure at a certain level which may be equal to the initially estimated one at the design stage. Bayesian reliability analysis method is applied to the evaluation of the results of repeating inspections of hull structural members to be incorporated with improvement of the reliability of ship structures. A general formulation is given on the following assumptions that (1) fatigue life of the structural member considered follows a two-parameter Weibull distribution, (2) its scale parameter is unknown, and (3) the uncertainty of inspection is introduced as the average detectability which is determined from the probability distribution function of fatigue crack size and the detectability of certain size of a crack.
Actual inspection records are analysed by the proposed method to proove its effectiveness for estimating the safety of ship structures after inspections.