The Inspection of Offshore Wire Ropes: The State-of-the-Art

Abstract

ABSTRACT This paper discusses problems associated With the inspection and discard of wire ropes used offshore. Rope degradation mechanisms are reviewed. Special attention is given to conditions that can lead to internal damage. Electromagnetic (EM) nondestructive inspection methods and their emerging role for offshore application are discussed and illustrated by examples, which include crane ropes, mooring ropes anddiving bell hoist ropes. INTRODUCTION Because the reliable and safe use of wire Ropes is crucial to offshore operations, concern with their integrity is a constant preoccupation of safety authorities and users. In spite of these concerns, a reluctance to apply appropriate wire rope inspection methods and discard criteria compromises the safety of many offshore operations. More dependable inspection methods, combined with a better understanding of degradation mechanisms and discard criteria, can notably increase wire rope safety. Because many offshore ropes deteriorate internally, their inspection solely by visualmethods is unsafe. For these ropes, reliable inspection procedures are particularly important. In other cases, visual inspection is possible but may not be practical. For example, mooring ropes are often covered with mud and marine growth. This makes their visual section difficult or, impossible1,2. Following the API recommendation of washing the rope with a high pressure water jet, is both time consuming and can remove valuable lubricant/blocking compound. On the other hand, electromagnetic(EM) inspections at regular intervals can significant increase the safety of offshore ropes. EM inspections are particularly effective when they are combined with visual examinations as part of a comprehensive inspection program, Electromagnet and visual wire rope Inspections complement teach other. Both are essential for safe rope operation, and both methods should therefore be used for maximum safety. Because EM nondestructive examinations Provide an important addition element of Wire rope inspection, the thrust of evolving regulations is clearly toward combinedperiodic EM and visual inspections. Furthermore, wire rope inspection andRetirement standards are becoming simpler and more lucid. Future guidelines will be easier for inspectors to interpret and for rope operators to fulfill. A thorough inspection must considerable aspect sofa rope' condition, including:the finding sofa visual inspection,the results of an EM rope inspection,the rope's operating conditions and Related damage mechanisms,the history of the rope under test and That of its predecessors. 4,5 Users as well as regulatory authorities Recognize that careful inspections canSignificant increase the safety of wire ropes. More over, dependable inspection procedures, Using combined visual and EM methods, can detect rope deterioration at its earliest stages. Therefore, wire rope user scan employ them as an effective preventive maintenance toolTo illustrate, here are some practical examples'.5The early detection of corrosion allows Immediate corrective action through Improved lubrication.Accelerating wear and interstrand Nicking can indicate a need to reline sheaves to stop further degradation.Careful inspection scan monitor theDevelopment of local damage at the