The approximately £200,000 project for South West Water involved Seacore initially positioning and jacking up Skate IIE over the proposed pipeline extension on the seabed and close to the existing discharge. Flow through the outfall was stopped and diverted through a temporary pipeline positioned and anchored to the cliff face. Sections of new 200mm diameter HPPE pipe, prepared on the platform's deck, were lowered overboard and fixed by divers to the seabed with rock anchors.

The divers then fixed shuttering around 6m long sections of pipe in turn, prior to placing underwater concrete as a 500mm thick protective covering for the outfall back to the landfall transition. The concrete was batched on the platform and lowered down in skips from Skate IIE using the on board National marine pedestal crane.

On completion of the offshore section of the pipeline the jack up was moved, repositioned, and jacked up again on a rock ledge at the base of the cliff face.

Equipment was transferred by crane from Skate IIE to the cliff to assist with breaking out the concrete surround and removing about 100m of the existing cast iron pipeline in a trench which zig-zagged down the cliff face.

The existing pipe was replaced with fusion welded 200 mm diameter HPPE pipe connected to the seaward section and tested prior to covering with a minimum 150 mm thickness of concrete batched on the jack up.

The temporary outfall was then disconnected and removed, the flow being diverted through the new run of pipeline on land and intertidal zone and out through the outfall extension.

MJ Information 17933