West Navigator

 West Navigator – Changing bearings in Riser Tension Sheaves

The Seadrill owned drill ship “West Navigator” had a yard stay at Vestbase in Kristiansund in November / December for classification works. As a part of this work, Scana got the assignment of changing the bearings in the Riser Tensioning system onboard. The job was done during a two-week period with continuous shifts, and was completed well within the time frame.

The Riser Tension system is based on large compensators mounted on the aft deck of the ship. The tension is transferred via wires alongside the ship and in against the moon pool, with the wire running over a series of sheaves. The sheaves are mounted two and two together in sheave boxes, each box weighing approx. 2500 kg. The task consisted of the disassembly of sheave boxes and existing bearings, installation of new bearings and assembly.

Scana was responsible for the mobilization of both personnel and equipment for the job. Hydraulic cylinder jacks and a specially designed jig were used for the disassembly of locking bolts and bearings. The bolts and new bearings were frozen using carbon dioxide snow before pressed in. The job was done partly onboard the drill ship and partly in the quayside workshop on Vestbase.

Scana Offshore Vestby AS has dedicated service personnel for work offshore, on site and in our workshop at Vestby. Our service personnel is used to handling work permit systems and safe job analyses (SJA) as a natural part of the working day.