Red7 jackup at work in the Scilly Isles

Red7Marine’s latest jack up barge, Haven SeaSeven, which has a 400 tonne deck load capacity, was delivered from the builders Combifloat BV (Rotterdam) directly to its first contract in the Isles of Scilly port of St Mary’s, where work has started on a 25 x 15m quay extension.

This self-elevating platform C7 series was purchased new specifically for this contract by Red7Marine Ltd, increasing their fleet to 10 self-elevating platforms. The 30m x 18m Haven SeaSeven is made up of modular pontoons that can be asembled in different configurations, The barge is fitted with 4 no. 48” diameter 38.5 mtr long spud legs and is jacked up and down by a hydraulic jacking system. It is being used as a working platform during the construction, carrying a 300 tonne crawler crane and manned by a Barge Master (IJUBOA certified) and one Marine Supervisor.

The main contractor Kier Infrastructure was awarded the contract worth £9.8m in August 2014, with funding provided jointly by the DfT and the European Regional Development Fund (ERDF) for economic regeneration projects promoted primarily by the public sector.

The works include the construction of a 25m long by 15m wide extension to the existing quay, the construction of a new 40m long quay wall, the relaying of a cobbled footpath and upgrades to some of the existing harbourside buildings, including a new ticket office and freight office, a refurbished waiting room and covered pedestrian walkway. The extension works are scheduled to be completed by August 2015.

St Mary’s is a private harbour owned and managed by the Duchy of Cornwall that caters for around 2000 visiting yachts each year. Other harbour users include fishing vessels and local boats and the Isles of Scilly Steamship Company’s passenger ferry Scillonian III (1977/1346gt) and the freighter Gry Maritha (1981/528dwt), which provide the Island’s connection to the mainland, some 30 miles to the east. Off island cargo delivered by these ships to the Quay is then transferred on to a smaller vessel, Lyonnesse Lady, for onward delivery within the Scillies archipelago. During last winter one of the Gry Maritha’s voyages was postponed following concerns about the condition of St Mary’s Quay, which had sustained damage during recent storms. The tug Polmear has been brought in for three months to assist berthing the ferries while the construction plant is on site.

The Islands also welcome dozens of visits by cruise ships that bring passengers ashore by tender, along with sail training vessels, large super yachts and special cargo deliveries. Visiting commercial vessels include HM Customs and Coastguard vessels, specialist survey, angling and diving vessels, and the Trinity House lighthouse tenders Patrica and Galatea.

The quay extension will be made up of 72 pre-cast concrete blocks stacked in 11 overlapping layers. The blocks, which are 3-4m wide, 15m long and weigh between 55-65t, are being fabricated in Plymouth and delivered by barge to the site where they will be lifted into position by the crane positioned on the Haven SeaSeven, which is fitted with a 38m boom (max lift 70 tons at 20 metres).

The site work began in January this year when Kier positioned two large anchors and chains for temporary storage adjacent to Old Quay in anticipation of the arrival of Jenkins Marine’s cargo barge JML 35, with a 65 ton excavator. A Notice to Mariners also advised that two moorings had been established in this location to be used by the barge during bad weather. Mariners were also advised that as part of the quay development there would be significant dredging works taking place off the end of the quay to level the sea bed to set in a frame to take the pre-cast concrete blocks.

In March the Haven SeaSeven was deployed. This brand new vessel was towed to St Mary’s Roads by Falmouth based workhorse MTS Indus (24t bp) and then transferred to the smaller tug MTS Vulcan 2, a Damen Stantug 1606 with a bollard pull of 17 tonnes, which took it to the inner berth within the harbour.

From early March, mariners were advised that, as part of the works dredging the footprint for the quay extension, Kier would be upgrading to 24 hour working, and the contractor expected to complete this part of the job by the middle of March. At times when the dredge barge was on station a buoyed anchor would be deployed off the stern of the barge. The dredge barge had finished its work by late April and returned to the mainland.

Kier Infrastructure have made strenuous efforts to keep the local population onside during the unavoidable upheaval created by this reconstruction. The company acknowledges that St Mary’s is small and close knit community of some 1500 islanders heavily dependent on the quay for their main livelihood – the growing and marketing of spring flowers. The quay also provides a lifeline to all the Islands’ businesses and residents.

Kier have worked closely with the local planners and council officers, Harbour Master’s office and harbour users groups to ensure the inevitable disruption is kept to a minimum. They have also instigated beach clean-up operations during downtime and have committed to supporting the local fisheries with their lobster and crawfish tagging programme.

Following the original design, the widening of the quay had to be redesigned in order to encapsulate heavy contamination which was found during routine soil sampling. Installing the precast blocks was set to begin towards the end of May, following approval from the EA and the Marine Management Organisation (MMO). The Harbour Master has been keeping everyone notified through this social media outlet. https://twitter.com/StMarysHbr

Visit Red7Marine on stand D37 at this year’s Seawork International.

By Graeme Ewens