Subsea trenching and excavation pioneer, Rotech Subsea, has secured a contract for a second phase of vital infrastructure works at a state-owned wind farm in offshore Taiwan - and at the same time has secured a commission to supply an additional spread of equipment for a wholly new campaign for the same client which will run concurrently.
With another campaign in the country set to commence in early 2021, the company will execute three campaigns simultaneously in Taiwan as well as completing an umbilical post trenching scope offshore Melbourne, Australia.
Inter-array & export cable trenching
Aberdeen-based Rotech Subsea completed an initial scope of work at the Taiwan site in Q2/3, 2020 which saw its state-of-the-art TRS1 suspended jet trencher carry out an inter-array and export cable trenching scope for a major long term tier one client.
The scope of work consisted of burying a total of 21 cables - four export and 17 array - to client specification of 2.1m DoL. The project was completed in two stages. The TRS1 tool was selected by the client due to its unparalleled technical and performance capabilities resulting in increased productivity and a reduction in total project costs.
The subsea spread of equipment was mobilized for the two-stage scope of work on the Willem De Vlamingh and Grand Canyon II, deployed using the ships’ cranes to water depths ranging from 8-29m LAT.
Stage one of the project was a success with four export and 17 array cables buried with ease. Soil conditions were soft sands, however, large sections of stiff clay with strengths up to 80kPa were experienced. Despite this, the TRS1 excelled and lowered the cable with two passes at an average rate of 4m/min reaching speeds up to 10m/min in some sections.
“The second phase of this project is set to commence in early 2021 with the client having already requested to keep the TRS1 tool on stand-by in Taiwan to ensure its availability,” said Director of Subsea, Stephen Cochrane. “It’s fantastic that the client has also requested another TRS1 for an additional campaign which will run concurrently.
“We are delighted to secure this follow-on work and new campaign, which firmly establishes us as the method of choice for cable trenching in the region. Our experience and performance in these scopes mean we are now seeing more and more that our Suspended Jet Trenchers are being chosen as a primary method for trenching, over other contact trenching systems and ploughs. Because of the enhanced capabilities of the RS tools, they can provide deeper and narrower trenches than ever before, with trenching speeds more than double that of competing Mass Flow Excavation tools.”
Rotech Subsea’s in-house research, development and engineering team has created a suite of 14 tools that has established Rotech Subsea as market leader in providing non-contact Controlled Flow Excavation (CFE), Suspended Jet Trenching technology and related subsea services. The dedicated in-house R&D team continue develop their technology, with further game changing enhancements to CFE due to be unveiled in 2021.