The purpose of the underwater inspection of F(P)SO and FSU hulls is to verify the floater's integrity and ensure the safety of personnel and production equipment. It is required by internal rules and by international maritime conventions applicable to floating units.
Today, hull inspections are performed by divers who operate in relatively deep waters (down to 30 m), on live installations and in an open sea environment subject to swell and variable weather conditions, all of which add up to significant risks for the divers' safety. These operations also involve mobilizing considerable logistic means for several weeks (support ships, decompression chambers, numerous teams).
An integrated solution has therefore been developed to perform this task with dedicated ROVs. It offers important advantages not only with regard to safety by limiting the number of diver interventions and thus the risk of accidents, but also in terms of reducing OPEX, as the HERO can operate for longer than divers and in harsh sea conditions which usually limit the duration of diving campaigns.
HERO is now under qualification and the first industrial trials have started.
This paper develops the method for specifying the equipment, positioning the system with NDT measurement tools (CP and US probes, magnetic sensing), HP cleaning and operational deployment. It also presents the results of various qualification tests carried out in the laboratory and the harbor to develop this new technology such that it satisfies hull inspection specifications.
HERO inspection methodology and performance have now been qualified by the main classification companies (Bureau Veritas, Lloyd's, DNV, and ABS).
The main applications envisioned for this solution are:
Underwater inspection in lieu of drydocking (UWILD) for classification requirements
Accurate hull evaluation for life-extension purposes
Assessment of floating assets prior to sale or conversion