Specialist synthetic fibre and steel wire rope supplier Lankhorst provided rope for the installation of a 1,110 tonne permanent living quarter module (PLQ) on an offshore gas platform in the Caribbean.
Comprising a control room, living quarters and a helideck, the PLQ module was installed on Dolphin Platform - one of three offshore gas rigs in Trinidad and Tobago’s East Coast Marine Area.
The upgrade project for Shell Trinidad & Tobago Ltd., Lankhorst was commissioned by heavy lifting company Seaway 7, a division of Subsea 7, which was contracted to carry out the lift.
The company provided three of its Lankoforce rope slings for the lift, each with a different diameter of rope and featuring a polyester protective braided jacket. The slings also had hard wearing, low-friction Dyneema HMPE fibre sleeves at the lift points and crane hook to help ensure proper load distribution.
Two 520 tonne minimum breaking load (MBL) slings were used on the heavy lift operation; one measuring 104 metres long with a rope diameter of 64 millimetres and the second measuring 47.2 metres with a diameter of 76 millimetres. The third sling, with a load capacity of 1,300 tonnes MBL, measured 46.1 metres and used a 108 millimetre rope.
Lankhorst said tight tolerances are critical to heavy lift projects such as this. Variations in sling lengths lead to uneven load distribution, called skew loading, in the object to be lifted and as such can impact the structural integrity of that object.
While the project required the slings to have tolerances of +/- 1 per cent of nominal length, Lankhorst said that by using Precision Tension Solutions it had achieved tolerances of +/- 0.1 %.
Wilco Stroet, Lankhorst Ropes managing director, said, “With the slings for Seaway 7, we’ve shown that unprecedented levels of tolerance accuracy can now be achieved with fibre slings even where different diameter ropes are used to prepare the slings.”