Dry, clean removal with no water waste or containment required
Faster turnaround on safety-critical deck surfaces
The West Venture is a fifth generation semi-submersible drilling vessel built by Hitachi in 2000 and registered in Norway. Classified by DNV as a 1A1 Drilling Vessel, the West Venture measures 117.60 metres in length and 69.70 metres in breadth, with a water depth capability of 1,800 metres and a drilling depth exceeding 9,000 metres. The vessel accommodates 114 persons across 57 cabins and is equipped with dual derricks for simultaneous drilling operations.
In December 2004, RPR Technologies was engaged to carry out paint and rust removal from the primary escape routes and walking areas of the vessel’s deck while operating in the Norwegian sector. These areas are among the most safety-critical surfaces on any offshore drilling vessel, as the condition and anti-skid properties of the deck coating directly affect the safety of personnel moving around the vessel in demanding offshore conditions.
The existing deck coating was an anti-skid system that had deteriorated over time, with areas of rust and flaking present across the surfaces to be treated. The paint thickness ranged from approximately 3 to 5mm. The scope of work required full removal of the old coating and rust to a specified surface cleanliness standard, followed by a surface wash and the application of a new anti-skid coating system to a total thickness of 1,500 microns. The project was completed between 2 and 8 December 2004 with RPR Technologies representative Tom A. Baann present on site throughout.
Carrying out coating removal on the deck of an active offshore drilling vessel in the Norwegian sector presents a set of challenges that go well beyond those of a standard onshore job. The primary escape routes and walking areas of the West Venture are high-traffic, safety-critical surfaces that must be maintained to a reliable anti-skid standard at all times. Deterioration of the deck coating in these areas creates genuine slip and trip hazards for the 114-person crew operating in often harsh offshore conditions.
The old anti-skid coating had accumulated to a thickness of 3 to 5mm and presented areas of rust and flaking that needed to be addressed before a new system could be applied. The contract requirement specified removal to Sa 2.5 on painted surfaces, a near white metal standard that demands thorough and consistent removal across the full treatment area.
Previous experience on comparable jobs using ultra-high pressure (UHP) water jetting had proven the method to be time-consuming and operationally burdensome in an offshore environment. UHP jetting generates large volumes of contaminated water waste, requires extensive containment to prevent runoff across the deck and into the sea, and creates wet working conditions that extend drying times between the removal phase and the application of the new coating. On an offshore vessel where downtime is costly and working conditions are already demanding, these inefficiencies represented a significant operational and cost burden that the client was keen to avoid repeating.
RPR heat induction technology was deployed on the West Venture to carry out the deck coating removal in a staged, section-by-section workflow suited to the operational demands of an active offshore vessel. The treatment area of 150m² was divided into sections of approximately 40m² each, with each section completed within 1 to 2 hours before being washed, dried, and primed with the first coat of the new coating system. The following section was then treated the next day, allowing the recoating programme to advance progressively across the full treatment area without disrupting vessel operations or leaving large sections of bare steel exposed overnight.
The RPR system thermally disbonded the aged anti-skid coating and rust from the steel deck substrate cleanly and efficiently, without the use of water, abrasives, or chemicals. This kept the working area dry and clean throughout the process, eliminating the containment requirements and extended drying periods associated with UHP water jetting. The absence of spent abrasive media or contaminated water also meant the waste stream was minimal, consisting only of the removed coating flakes.
The achieved surface cleanliness was Sa 2.5 on painted surfaces and Sa 2 on rusted areas, meeting the contract specification across the majority of the treated area. The entire 150m² scope, including a final downwash of the complete job area and the application of a finish coat to a total system thickness of 1,500 microns with anti-skid, was completed within 6 days. The estimated total time saving compared to UHP water jetting on a comparable job was approximately 5 days, a significant efficiency gain in the context of offshore operations where vessel time and crew productivity are closely managed.
