Netherlands-based DNC Diving deployed a compact version of a Saab Seaeye Cougar XT during its project to cut off 194 grouting hoses from 97 structures in 24 days.
The project incorporated a tooling package created by DNC Diving into its Cougar XT Compact, a robotic system which is designed for handling strong currents around wind farms.
Fred Bosman, ROV operations manager at DNC Diving, explained: “We first attached a hydraulic clamp on the upper part of the grouting hose, which was connected to both the Cougar and vessel cranes.”
“Once the clamp was secured to the grouting hose the ROV was pulled back from the clamp so the hose was no longer connected to the ROV but only to the vessel crane.”
He continued: “Our next step was to cut the hose as close as possible to the lower side of the hose and the last highest cut just underneath the coupling.”
This low cost solution for removing the grouting hoses originated from combining a Seaeye hydraulic power pack with a miniBOOSTER and a TNT Rescue ‘Jaws of Life’ hydraulic rescue cutter to create a unique system.
The task for the compact Cougar also included offloading 58 tonnes of the grouting hose into containers.
Mr Bosman added: “At the time the hose was no longer connected to the structure and the vessel crane recovered the hose to the deck where it was stored in an open-top container until off-loaded in port.”
“Depending on how close we could position the cutter to the couplings, the remaining hose lengths were about 6m long and weighed about 300kg each.”
By Alice Mason