APB Wavebreak

The project involved the design, construction and installation of a floating concrete wave-break structure and anchorage system to protect the Town Quay Marina. An existing wavebreak in the same location was removed as part of the contract works.

Mackley undertook the design, construction and coordination of the replacement of the old inner breakwater with new larger concrete units to provide protection to the marina moorings and Red Funnel Red Jet passenger pontoon from the sea wave action and swell.

The client provided works information that included a performance specification and details of the existing wavebreak.

Manufacturers of the new proposed large wavebreak units are all outside of the UK, so Mackley negotiated with a supplier to have a bespoke mould made abroad and brought to the UK. The pontoon units were then made on the quay side adjacent to the site in the UK at Town Quay, thereby saving shipping from abroad and providing craneage into the water direct from the casting yard. A saving of approx £100,000 was provided to the client for this local manufacture initiative.

The design of the moorings was in-house, independently checked by marine consultants. The use of stub piles as mooring anchors was explored, however after investigation under sea obstructions were discovered. We therefore resorted to traditional concrete mooring blocks as restraints with heavy duty chains.

During the production of the new concrete units significant advancement was made in the knowledge and skills required for the use of self compacting concrete in the production process. This removed the need for vibration compaction and overcame the problems associated with the restraint of shutters and floatation of polystyrene buoyancy within the moulds.