In 1999 Stolt Offshore were commissioned by Mossgas/PetroSA to install the new Control Buoy for controlling flow from the new EM field to the FA platform. This EM Control Buoy is tethered down to a large caisson gravity base on the seabed below in 100 metres water depth.

In order to safely lower the caisson down to the seabed Wale Marine were commissioned by Stolt to design, fabricate and supply certain bespoke rigging and sub-sea equipment, including the tripod structure connected to the caisson and the intermediate rigging to a specialised 100 cubic metre compartmented stabilising buoy capable of sustaining 100 Te per square metre of external pressure.

The stabilising buoy was made from nested large diameter spirally wound steel pipes with domed ends.

During the pull-down of the semi-submersible stabilising buoy one of the subsea 100 Te snatch blocks failed and it was necessary to design and fabricate a new one as an emergency supply. This Wale Marine effected between receiving the go-ahead at noon on a Friday to test loading the snatch block to 120 Te in a test bed at 5 am the next day.