INTRODUCTION: WOOD IS AN ENGINEERING MATERIAL WHICH HAS WIDE APPLICATION IN MARINE STRUCTURES, SO ITS INSPECTION, MAINTENANCE AND REPAIR NEED CONSIDERABLE IMPORTANCE. SIMILAR TO ANOTHER ENGINEERING MATERIALS, DURING SERVICE LIFE, WOOD A S A MEMBER OF MARINE STRUCTURE IS SUBJECTED TO DIFFERENT TYPES OF DEGRADATION AND DESTRUCTION (CHEMICAL, PHYSICAL, MECHANICAL AND BIOLOGICAL) WHICH DECREASE THE RESIDUAL STRENGTH OF WOODEN MEMBERS. THEREFORE, THE ASSESSMENT OF DEFECT AND ESTIMATION OF RESIDUAL STRENGTH IN WOODEN MEMBER IS NECESSARY TO PREVENT THE FAILURE IN STRUCTURES. SINCE THE INSPECTION AND EVALUATION OF MARINE STRUCTURES IS AN IN SITU (OR IN SERVICE) INSPECTION, SPECIAL METHODS WHICH ARE APPLICABLE FOR IN SITU INSPECTION WITHOUT DAMAGE TO INSPECTED MEMBERS ARE NEEDED. NONDESTRUCTIVE TECHNIQUES HAVE SUCH ABILITIES.