ROYAL YACHT SQUADRON BREAKWATER, COWES
For civil engineering schemes valued at under £3 million.
Sponsored by Mott MacDonald.
Sailing may be the raison d'être of Cowes, on the Isle of Wight, and the Royal Yacht Squadron (RYS) - the choice club at the heart of that tradition - but no divine rights are attached. When squadron members decided it would be rather convenient to have a little harbour to moor craft outside their elegant clubhouse, RYS had to go through the planning hoops just like everyone else.
Constraints due to the possible impact of piling vibrations on delicate shoreline properties and minimising the visual impact of the breakwater above high-water level drove the design. The end result is a beautifully crafted miniature harbour constructed at a very modest cost.
A long-reach hydraulic excavator mounted on a small jack-up barge enabled the stiff clay below the seabed silt to be machined level, in preparation for the crane-lifted open-base concrete caissons forming the main breakwater structure. Concrete base plugs were cast in place and topped with surplus spoil to ballast the wall.
Sleeved precast capping beams were then threaded over long holding-down studs to complete the fixed structure.
Some 6,000 tonnes of rock armour from just along the mainland Jurassic coast were dug as overburden from the building-stone quarries near Swanage.
Obtrusive walls or handrails were eliminated by making the breakwater out of bounds. Sailors must keep to the separate pontoon-mounted gangways.
Client Royal Yacht Squadron Cost £1.4 million Principal designer Walcon Marine Contractor Dean & Dyball Construction