Vertech were awarded the contract for the removal of six bend restrictors located on the underside of the Ithaca APL Mooring buoy.
The existing flowlines/ umbilicals and anchor wires were cut infield and then transported by a twin pontoon Heavy Lift Barge within the Moray Firth Estuary. A total of six bend restrictors required removal to allow for future storage of the APL Buoy, three with flexible flowlines, two with control umbilicals and one with a blanking plate.
Initially each bend restrictor was disconnected from its mating flange on the Buoy and lowered to allow access for Divers to install the Diamond Wire Cutting Machine allowing a cut at each location to be made close to the underside of the Buoy. Once cut & lowered clear of the Buoy each bend restrictor and flexible flowline/ umbilical was cross-hauled to the outer edge of the buoy and recovered by crane to a Multi-Cat barge.
On completion of the recovery of the bend restrictors to surface the Anchor wires were required to be cut near the socket using a hydraulic wire cutter.
Diving operations was carried out from Vertech’s Daughter Craft “Vaila” using 40/60 Nitrox on a 24 hr basis with two teams carrying out 12hr operations each. Diving operations was carried out using a single diver to carry out the workscope.
Operations were carried out to a maximum depth of 25m.
The Vaila was moored to the lift barge throughout the project with shift changes carried out by an FRC transiting from Nigg Energy Park (NEP at the start and end of each shift.