ABERDEEN, UK – Rotech Subsea has accomplished a three-phase pit cleansing, cable reducing and de-burial scope on the Borssele and Triton Knoll offshore wind farms within the North Sea for an unnamed dredging and marine specialist.
The corporate used its TRS1 and TRS1LD jet trenching instruments for pit clearing and cable reducing at Borssele within the Dutch North Sea and grout bag and cable de-burial at Triton Knoll in English waters.
Throughout phases 1 and a pair of, the TRS1 software was used for 2 pit cleansing operations. Throughout part 3, the TRS1LD was used for post-lay trenching to a specification of three.0 m DOL and cable de-burial.
The mission started in 1Q 2020 and was accomplished in 2Q 2020. The gear was mobilized on the tug Zwerver III and deployed utilizing its crane. Water depths ranged from 8-55 m (26-180 ft) LAT.
Stephen Cochrane, Rotech Subsea Director, stated: “The bellmouth pit excavation was roughly 30 m x 50 m x 4 m [98 ft x 164 ft x 13 ft], and we efficiently saved the pit open regardless of 1.5 m [4.9 ft] of sand migration each 12 hours.
“The cable reducing was accomplished with ease, too, with some sections requiring 4.5 m [15 ft] DOL.”
In accordance with the corporate, soil circumstances at Borssele ranged from sandy circumstances close to shore to tougher soils as much as 85kPa UUS farther out to sea, attaining a mean progress price of two m (7 ft)/min. About 100 m (328 ft) of cable and grout luggage had been de-buried from 2.5 m (8.2 ft) beneath MSBL, permitting the shopper to begin cable removing operations.