Poole Harbour has always been popular with the watersports fraternity.
Its 4,000ha of sheltered waters provide the ideal venue for dinghy sailors and jetskiers alike. Visiting yachtsmen and women also like to drop in.
But, although there are some occasional moorings for visitors scattered along the harbour's extensive shoreline, few are conveniently close to the historic centre of Poole.
Most visitors would prefer to tie up at the Town Quay, right by the original home of the worldfamous Poole Pottery, and close to shops and restaurants. But until recently facilities were limited, with visiting boats forced to raft up and share the limited protection afforded by a small rock breakwater with the local inshore fishing fleet. This breakwater also left much of the Town Quay exposed.
'Unfortunately, old Poole town centre lies below the level of the quay, ' explains Poole Harbour Commissioners harbour engineer Dick Appleton. 'This means that if waves overtop the quay we get flooding behind it.'
So there were three good reasons for improving facilities at the Town Quay - more space for big-spending visiting yacht crews, safer moorings for the fishing fleet and straightforward flood prevention. Funding, however, was a problem, so the project was put on hold.
The commissioners had no tradition of investing in leisure facilities. Maintaining the commercial port and the ro-ro ferry berths had to be top priority.
Although grants from the Environment Agency and the Ministry of Agriculture, Fisheries & Food would help, a large chunk of the estimated £2M+ cost of a larger breakwater and associated facilities would have to come from elsewhere.
Enter Poole Pottery. It planned to move its production to a new industrial estate on the outskirts of town and redevelop its waterfront site as retail and residential properties. More high-class leisure moorings on its doorstep would be an obvious selling point. Last July, the pottery and the commissioners formed a joint venture company, Poole Harbour Services, and Hampshire-based Dean & Dyball landed the £2.1M construction contract 12 months after being sent a conditional letter of intent.
'The delay while the funding was sorted out turned out to be a benefit, ' says Dean & Dyball regional manager Owain Phillips. 'It gave us the time to refurbish our workbarge, Doreen Dorward, and the knowledge that we had five months of work for it at Poole made refurbishment much more financially attractive.'
From the contractor's point of view, the project fell naturally into four distinct phases. The 250m long existing breakwater had to be removed, with most of its core material being re-used in the new 460m long structure. Up to 800t of Purbeck limestone a day - boulders weighing up to 3t - have to be placed and trimmed to level. Where the breakwater lies close to the deepwater shipping channel, two wings of sheet piles had to be driven to form the western 'hammerhead'. And more than 60,000m 3of material has to be dredged out of the new haven and dumped at sea.
Phillips says that, to minimise disruption in Poole, the base where the rock is transferred from road transport to a fleet of three flat top dumb barges was set up in the commercial port, on the opposite side of the shipping channel from the Town Quay.
'We had to sheetpile the old Ballast Quay before we could start - and we'll have to renew the copings and surfacing once we finish - but the convenience of unrestricted access and no problems with noise restrictions makes it worth it.'
A hydraulic excavator fitted with a five finger grab is used for loading the rock. Similar machines on the Doreen Dorward and on the breakwater itself complete the unloading and placing operations.
Dean & Dyball project agent Nigel Habershon says the weather so far this winter has been far from favourable. 'Wind is the real problem. We had a lot of gales at the end of November, and when the wind is from the south east, the waves have a fetch of 4.5km before they hit us.'
While driving the two runs of sheetpiles at the western hammerhead, the contractor ran into problems with more than weather. 'The ground was very dense and very hard - it all took longer than expected, ' Habershon says: 'Where there was a lot of clay we had to use an impact hammer to complete the driving when the vibrating hammer couldn't cope.'
Dredging subcontractor ML (UK) of Portsmouth has just finished dumping a total of 64,000m 3of material out in the English Channel. It used three former Dean & Dyball split barges for the muckshifting - as their name suggests they dump up to 300t of dredged material at a time by literally splitting open from the keel upward. Very little of the projected 42,000t of rockfill remains to be placed. Soon, Dean & Dyball will have started driving 50 tubular steel piles up to 508mm diameter and 15m long, which will retain pontoon berths for 100 visiting yachts and 75 local fishing boats.
Then all that remains will be some minor shore works, mainly a fisherman's car park and fish landing area. Everything has to be finished by the beginning of next month. 'We have to avoid the tourist season, ' says Habershon. 'In this area, the tourist is king.'