The deepest production unit
ever installed

Project: Riser pull-in sheaves for FPSO Turritella
Destination: Stones project, Gulf of Mexico, 2,900 metres deep

SBM Offshore commissioned Ropeblock to design and manufacture several frames and sheaves. The total weight of the Ropeblock scope amounted to about 60 metric tonnes. The rope sheaves used are suitable for HMPE rope ø 140 mm with a break load of well over 1,350 metric tonnes.

In order to compensate heave motion during buoy-to-turret coupling, the heave compensation rope sheaves are used in conjunction with a pendulum system. Once buoy and turret are coupled, the risers and umbilical ropes are pulled inside using the frames. Space within the turret is extremely limited, whereas risers and umbilicals need to be pulled in from several positions. That’s why, in order to save space and smartly guide the cable, all frames are made removable, with one frame being rotatable on a bespoke Ropeblock designed base plate.

For both heave compensation and riser pull-in the customer uses HMPE rope. The Ropeblock sheave used stands out by its groove’s being treated with a corrosion-resistant layer AISI 316. This prevents corrosion particles from accumulating in the groove that could in time damage the synthetic rope.

All blocks and sheaves were designed in compliance with the latest ABS regulations and manufactured under certified conditions. All sheaves and frames have now been delivered and installed. With proud Ropeblock contributed to Turritella's “first oil” milestone.