This document provides comprehensive guidelines for inspecting catenary mooring components of floating drilling units. It was developed in response to the need for an industry standard for such inspections. Some discard criteria for used chain and wire rope have been established and used by some manufacturers, regulatory bodies, operators, and drilling contractors. However, these criteria vary, widely and most of them cannot be applied directly to the mooring of floating drilling units. To ensure good mooring inspection quality and to form an industry agreement on discard criteria, this recommended practice was developed.
The need for rigorous, effective inspection of mooring hardware is apparent because most of the mooring failures involved faulty mooring components including corroded or physically damaged wire-rope or chain, defective connecting links, or mooring hardware of inferior quality.
This document should be useful to engineers and operating personnel concerned with the following:
a. Planning a mooring inspection.
b. Conducting or supervising a mooring inspection.
c. Deciding whether to reject, repair, or replace mooring hardware.
d. Communicating with others concerning acceptable mooring hardware.
This document compiles factors that are best understood and can be quantified at this time. The information in this document will be updated after further experience and knowledge are gained. Accordingly, we encourage comments and suggestions toward broadening and refining these guidelines.
Although this recommended practice was developed for moorings of floating drilling units, some of the guidelines may be applicable to moorings of other floating vessels such as floating production platforms, pipe-laying barges, and construction barges. The applicability of this document to other floating vessels is left to the discretion of the user.