Royal Refurbishment

Prince Charles was the prestigious client for this tricky quay expansion project on the UK's remote Isles of Scilly

Much like the famous castaway of Daniel Defoe's 1719 novel Robinson Crusoe, Errol Wisby knows all too clearly what it's like being a lonely Englishman marooned on a remote island.

Working as site agent for Nuttall John Martin on a complicated quay expansion project on the Isles of Scilly off the coast of Cornwall, not only must he live for weeks at a time in relative isolation many miles away from his friends and family, but he also has to shoulder responsibility for a complex logistical operation ensuring that multiple building materials are ferried in on time and accurately distributed among four island sites.

As if that wasn't enough pressure, the project client is none other than Britain's Prince of Wales, who in his capacity as the Duke of Cornwall is responsible for the upkeep of many facilities on the Isles.

All that and no tropical sun or coconuts!

Eager to get a better insight into the workings of the project, I asked Errol to give me a tour...

IT'S SCILLY SEASON
Worth roughly £3.5M, the project's one of 45 being carried out on the Scillies, including barn refurbishments, newbuilds, drainage and power projects, and it represents the largest single investment there by the Duchy of Cornwall. It involves the widening and lengthening of four quays on three islands two quays on Bryher (Church and Anneka), one on St Martin's (Higher Town) and one on St Agnes (Porth Conger).

"I can't emphasise enough the importance of these quays to the people of the Scillies," said Errol. "They're vital to life. Everything comes in three times a week on the freight vessel Gree from Penzance, which moors and unloads at the large quay on the main island of St. Mary's. Supplies are then loaded onto the workboat Lioness Lady, using a crane on the passenger vessel Scillonian III, which distributes goods among the various island quays for transport to their final destination by forklift."

Islanders know the lifeline the quays represent and most turn out on the waterfront to greet the Lioness Lady as she makes her rounds. The same quays are used to serve tourists - the main source of island income during the summer months - ferried about by the Scillonian III. But with some passenger access stairways less than 1m wide and the forklifts struggling to manoeuvre on narrow access ramps, several changes were required to improve the quays' overall safety.

Church Quay - work to widen the quay by 3m was recently completed. An initial jet probe investigation had revealed that the original construction was positioned on sandy gravel, so a new solid foundation surrounding the existing quay was installed and solid blocks placed on top.

Porth Conger - the construction method, currently under way, is similar to that of Church, but the presence of underlying bedrock granite meant no foundations were required. Instead, drilling was carried out to embed dowel straight into the rock (down to 2.2m), with columns of concrete blocks placed on top. Each precast block is 2m x 1m x 1m in size, but some are modified into various combinations of half, fullsize and corner blocks. When building the stack, mortar's used to bed the blocks, with the top blocks covered in grout before the covering plank's set in position and loaded to the right pressure. Divers are also working at the wet end of the quay, which now extends out an extra 10m.

Higher Town - exactly the same construction method as Porth Conger, but extended by 1.5m. This quay also requires divers to carry out some of the work because of a different tidal range.

Anneka's Quay - although existing foundations will remain, the timber deck has been completely ripped off and 18 new planks and steps are being cast on site by main supplier Ladds to relieve pressure.

New plinths are also being cast to raise the pier's level slightly to give it a greater range of tidal access (see the panel on page 17 to understand the reasons why).

"Once completed, this robust new quay will extend 12m it's so tough you could moor the Titanic to it," Errol boasts proudly.

HAND-TO-MOUTH
Of course, a major headache for any project as remote as this is logistics - ensuring the right materials arrive from the mainland at the right time is paramount.

“In an emergency there's a helicopter," admits Errol. "But most of the time I have to check that lead times are correct. The supply vessel comes in three times a week and advance notification for that is vital as it can only carry 200 tonnes each trip and much of that capacity is often already booked by other people on the islands. For example, if British Telecom wants two transits, that's 80% of the deck capacity already spent, leaving virtually no room for rebar or whatever. You've got to book in early! "

On-site storage is also limited: "We can't just haul in 600 tonnes of precast then leave it sat there like on a normal job; it's all hand-to-mouth here," says Errol.

The delivery procedure generally works as follows:
1). Precast units are fabricated on the mainland by Ladds, then taken to Penzance and booked on a supply vessel to sail to the Scillies
2). On arrival, materials are unloaded at the main quay on St. Mary's - where the project offices are also located
3). A landing craft then arrives to load some of them with its crane, which has to be scheduled for periods when the Gree - calling Monday, Wednesday and Friday - or the passenger vessel Scillonian III, which calls every day during the summer except Sunday, aren't busy using the quay.

"We were initially thinking of bringing in a 700¬tonne landing craft, but drip-feeding material like this has worked really well. The shipping company has done us proud," Errol enthuses.

Each quay is out of action during its construction, so Nuttall's landing craft takes responsibility for all inbound freight deliveries - perishable goods are containerised and off-loaded alongside construction materials on to a temporary pontoon provided by the Duchy. The pontoon moves from location to location as work on one quay finishes and work on the next begins.

FINALLY
With weather problems at Church Quay delaying construction by over two weeks, the handover of Porth Conger to Nuttall was slightly behind schedule. But work's now on track and Errol's confident that the entire project can be handed over to the client by the end of February 2008. He's also hoping Nuttall can land a forthcoming supplementary tender to build a new quay connecting St. Mary's to Rat Island.

In the meantime, he's off to the pub - locals and workers alike agree it's one of the best ways to avoid going stir crazy on their desert island!

Article courtesy of Dredging and Port Construction (November 2007)

Further Info

For further information, contact Peter Bishop, Head of Public Relations at:
Edmund Nuttall Limited
St James House, Knoll Road, Camberley,
Surrey GU15 3XW
Tel: 01276 63484
Fax:01276 66060
E-Mail: peter.bishop@edmund-nuttall.co.uk