FPSO Mooring Monitoring & In-service Inspection FPSO Research Forum Richard Leeuwenburgh College Station – May 1 st 2003

n Typical Classification Requirements n Bluewater Experience Contents

n ABS – Guide For Building and Classing Floating Production Installations n Bureau Veritas – Rules for the Classification of Offshore Units n DnV – Classification of Offshore Units n Lloyds Register – Rules and Regulations for the classification of a floating offshore installation at a fixed location Sources

General Requirements n Annual Survey Visual Inspection of critical components n Check for excessive corrosion and abrasion n Check mooring line angles n Bearing n Special Survey (3-5 year intervals) NDT on critical components n Joining shackles n Links at chainstoppers n Marine Growth n Sea-bed condition

General Requirements n Monitoring No real requirements unless design relies on it (Safety case) System is proof loaded and checked after installation

Bluewater Experience n 2 Opportunities on North Sea FPSOs for in-service inspection –NDT tests were executed (on deck of supplier) –Thickness measurements taken –No abnormal wear/corrosion observed –Thickness measurements are now reference

Bluewater Experience n ROV Surveys (annually) –No excessive abrasion/corrosion found –No change in pre-tension angles –Missing safety pins in link plates –Trenches at touchdown areas

Bluewater Experience n Monitoring –North Sea : All lines are equipped with inclinometers/proximity switches –Brasil : Tension measurements –All : Position measurements