Trialling new equipment can be a win:win situation for the design and fabrication team, providing the opportunity for passing on required knowledge about operating a new system to its new owners as well as providing the designer with practical experience that is a definite bonus for future designs. This was confirmed when IHC Engineering Business (EB) worked with Saipem UK Ltd (SUKL) on installation, commissioning and sea trials of two new EB-designed and built pipeline trenching ploughs aboard the Far Samson.
The main trenching plough was designed to bury pipelines up to 1550mm diameter up to 2.5m below the seabed, sustain a bollard pull of over 350T and maintain speeds of up to 3000m/hr, where seabed conditions permit. The backfill plough, an all-new EB-designed concept, sees all four of the main skids sit outside the trench enabling the plough to run on undisturbed soil, thus increasing stability and reducing risk of damage to the laid pipe.
"Over the course of six weeks an EB team worked alongside SUKL personnel and led the electrical installation and commissioning of equipment onboard the 'Far Samson' in preparation for the sea trails which were design to rigorously test all key aspects of both ploughs' performance," explains EB's Sales and Operations Director Toby Bailey. "The trials programme included a trenching plan that would test the ploughs' ability to transition in and out of work, demonstrate multi-pass capability, and allow operators to gain an understanding of the general performance of the ploughs in terms of speed, tow force, trench profiles, steering ability and overall control."
"Over the course of the trials, the ploughs performed exceptionally well in all of these areas," he adds. "The trenching plough was tested up to rated bollard pull and stable trenches up to 2.7m deep were created. Trenching speeds in excess of those expected or required were achieved and many of the new design features were proved to be a major advance on previous pipeline plough systems. For example, water jetting to aid with share closing and a novel system to prevent soil ingress into the skids.
During the course of the sea trials, the backfill plough concept proved itself to be highly effective. The plough was easy to steer and very stable, even at relatively high offset steering angles and provided effective backfilling of the 2.7m trench.
Upon completion of the trials, SUKL confirmed that it was extremely satisfied with the performance of the ploughs and all are now looking forward to the first 'live' trenching project."