Superyacht puts on weight send in the dredgers

21 May 2014
Jenkins Marine's Doreen Dorward was mobilised for the special task (Peter Barker)

Jenkins Marine's Doreen Dorward was mobilised for the special task (Peter Barker)

Jenkins Marine has taken part in an unusual dredging operation in Portsmouth to aid the return to the water of a superyacht which put on extra weight following modifications.

The luxury superyacht Shemara has spent several months at the Burgess Marine site at Trafalgar Wharf Portchester at the north end of Portsmouth Harbour, undergoing a complete refurbishment. The yard employs their 1,000t shiplift to transfer ships to and from the water, but following the extensive fit out and modifications to the Shemara it was found that the vessel had put on weight and was several hundred tons heavier than when it arrived. The consequential deeper draught required the shiplift to go deeper into the water to allow the vessel to float free. Siltation had however taken place in the backwaters of Portsmouth harbour meaning the shiplift was unable to go down as far as originally designed. Jenkins Marine therefore came to the rescue in a priority dredging operation.

The conventional method of using a backhoe was problematic as dredging was required in the 15m wide and 53m long area occupied by the shiplift resulting in the requirement to dredge beneath the structure. Jenkins Marine mobilised their dredger Doreen Dorward for the task, equipped with their 35t excavator. Burgess Marine assisted by fitting a 10t double drum hydraulic winch and power pack to the vessel’s foredeck enabling the use of a dredge plough to reach beneath the shiplift. The excavator dug a pit at the front of the dock with the dredge plough dragging material into the pit.

Excavated material was loaded into the attendant 150m3 split hopper barge Hurst which was towed to the disposal ground at Nab Tower by Jenkins Marine’s 15t bollard pull tug Handfast. The hopper barge discharge operation is controlled remotely from the tug. Dredging and disposal operations involved a 24/7 tidal working basis, dredging being completed over the low tide and sea disposal over the high tide periods. Burgess Marine were reported to be very pleased with progress especially as only one week’s notice was given prior to award of the works.