Spooling Flexible Flowlines

Instead, we used self-propelled modular transporters (SPMT) to rotate custom designed storage baskets (created by Harlyn) on the barge.

SPMTs have previously been used to help spool cable, but we are not aware that they have ever been used previously for large flowlines on a floating barge.

Given that this was a unique proposition, we carried out detailed ballast monitoring and offset trials to make sure we could look after the flowlines optimally in transit.

In order to manage the risk of the SPMT rotation, we prepared an initial project risk register, followed by a detailed storyboard to walk through each step of the operation.

We designed 3D models to replicate the operation in prototype.

Innovative engineering and bespoke storage baskets

One of our tasks on this project was to design and build baskets large enough to spool and transport 4,500 tonnes of flexible pipe.

We carried out finite element analysis (FEA) to analyse the effect of different stresses on the basket design, and prepared 3D models. When the design was approved and built, the three baskets weighed 1,500 tonnes each and measured 19m in diameter.

We transported the baskets from Newcastle to Port of Blyth, so that they were ready to receive the flexible flowlines from the manufacturing facility. To do that, we chartered the barges and arranged for towage between ports. Given the size of the baskets, we were managing the complexities of ballasting, mooring and emergency responses during their voyage. At Harlyn, we’re well-prepared for these types of operations and we used out our own lashing and securing, and our Harlyn Purpose Built Ballast System.