Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

Quays to survival: Rebuilding Scilly's lifeline

'If you kiss a girl in the nightclub tonight, we all know about it by tomorrow morning. Everybody knows everybody and everything and there are no secrets...

"It's good here, but..." says Steve "Geordie" Robertson, Nuttall John Martin's (NJM's) drill operator, about life as a contractor on the Isles of Scilly.

Lucky then that the contractor has done a super job of winning over the locals. "We've had some right wallies over here in the past, but these lads have been absolutely great," says Andrew Hewlett, whose friendly Paulger's Passenger Transport company meets all arrivals off the Skybus, the Island's dedicated airline. "I tell anyone who asks, these are great lads."

How often does a contractor earn such praise from a community? Not often. But then, how often is a contractor playing such a direct role in securing that community's future existence? Because it is that simple – unless Scilly's network of quays is upgraded, the Health & Safety Executive will shut them down, and with that would go their only means of connection with St Mary's, its main island, and the mainland itself.

The quays were effectively condemned because they are simply not fit for purpose – narrow and only accessible during certain tidal ranges. Foot passengers would have to fight it out with forklifts unloading cargo to get from boat to dry land.
Which is why Nuttall John Martin is now midway through a £3.5M project to upgrade four of these vital lifelines – one on St Martins, two on Brhyer (one built by Anneka Rice no less, in her 90s TV series Challenge Anneka), and one on St Agnes.

Client for the job is the Duchy of Cornwall and engineer Beckett Rankine. But the real client is, of course, the islands' 2,000 inhabitants.

Rebuilding the quays, of course, means taking them out of action – severing the Islands links to the outside world. On each quay a temporary pontoon has been erected for foot passengers whilst NJM's landing craft is used for supplies. Naturally, the locals are anxious for work to move swiftly.
"On Bryher they keep giving me grief because Anneka built her quay in 72 hours whilst I've been there for three weeks and its still not finished," moans NJM project manager Errol Wisby.

But all in all, Wisby's charm offensive has worked. Innovative ideas such as doing away with site vans and instead buying the 20-strong workforce bicycles to get around the main island and using the local boating association to get the workforce to and from the others really made an impression.

"Why do we need vans? We’re all out on the islands and not having guys screaming around the island's lanes went down really well. And using our own boats would have been a real poke in the eye to the locals. With just 2,000 people on the islands word doesn't take long to get around that you’re good or bad."
Wisby's real challenge on the job though has been logistics. Technically, the work is not overly complex (see diagram), but simply getting the materials to site, when it all has to be shipped from the mainland, transferred onto a landing craft and then delivered "just in time" to up to four work sites is not easy.

"What makes it difficult is we are 37 miles out into the Atlantic and it's not like you can just nip down to Jewsons for a new drill bit. If we need something racing over, it has to be by helicopter, else we have to wait for the Gry Maritha," says Wisby, referring to the freight ship that brings supplies from the mainland three times a week and needs booking at least a week ahead.

"And we're restricted in space on the sites – we can't have 600t of precast blocks sitting ready for when we want them in a field. We have to make sure its all delivered hand to mouth."

With such heavy reliance on delivery by sea, weather was always going to be a major risk on the job, and there are "large chunks" of float built in to allow for weather delays – NJM is not contracted to finish until July but is aiming for the end of February.

ANNEKA'S QUAY

Work: extend by 12m to allow it to be used in lower tidal ranges

Method: the timber deck has been ripped off to allow the existing sand filled concrete caisson foundations to be reused. Two new piled foundations are being installed to provide the additional length and 18 concrete planks are being cast to form the new deck.

Programme: under way

CHURCH QUAY

Work: widen by 1.5m either side

Method: founded on sandy gravels, the method was to construct an 800mm deep reinforced concrete footing surrounding the existing quay with Gewi anchor bars cast in. Precast mass concrete blocks 2m long by 1m wide and 1m deep were then threaded on top to form a pinned cantilever before the bars were tensioned, and a 205mm precast plank laid on top and fixed to the existing quay. A mesh reinforced topping slab completes the quay.

Programme: now complete
HIGHER TOWN

Work: widen by up to 3m on landing side and build new wave wall

Method: with identical ground conditions, construction method same as for Porth Conger (see right). Additional rock armour is also being installed.

Programme: yet to start
PORTH CONGER

Work: widen by up to 3m on landing side, extend by 9.6m and raise height of wave wall by 1m.

Method: founded on bedrock, NJM is drilling 2.2m into the rock and embedding the Gewi anchor bars at 1m centres. Bedrock levels are regularised using 40MPa mass concrete and blocks are again threaded on top.

Programme: underway

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Please note comments made online may also be published in the print edition of New Civil Engineer. Links may be included in your comments but HTML is not permitted.