In possibly its most ambitious project yet, the Royal National Lifeboat Institution is building a lifeboat building centre that - it hopes - will become a world class centre of engineering excellence, as Mark Hansford discovers.
Construction of a boat yard is not something that would normally feature in NCE. But this is no ordinary boat yard. The All-weather Lifeboat Centre (ALC) that the Royal National Lifeboat Institution (RNLI) is currently building at its HQ site in Poole, Dorset, aims to set the standard worldwide for lifeboat design and construction.
The facility will, for the first time, bring together on one site all-weather lifeboat design, production, maintenance and refit activities.
In simple cost terms, bringing lifeboat production in-house will save the RNLI in excess of £3M annually once the facility is fully up and running. It means the organisation will reach payback on the building in 12.9 years, after taking the phasing of work into account.
But the benefits to the RNLI - and UK shipbuilding expertise - go much further than that (see box). So it’s no surprise that the RNLI team building it are proud of their work, particularly as construction itself is no small matter.
First, there is the simple fact that the facility is being built on a harbour-side site. Sea levels are rising, and the RNLI had to carry out major work - building new sea walls and raising the entire site - before work proper could even begin. RNLI framework contractor Bam Nuttall was brought in to do this last year, with Jenkins Marine as dredging subcontractor.
Why? It’s simple, says RNLI head of estates management Howard Richings: “Bam Nuttall are our framework contractor, it is good at marine works, we work well together, and they are very good at getting on with it.”
Richings’ estates management team, is project managing this job. His manager on the ground is ALC project supervisor Iona Evans.
And there has been plenty to supervise. Works have included raising the level of the site by 1.4m and rebuilding the 187m quay wall in line with Environment Agency requirements. Steel sheet piles were used to form new quay walls and were driven 7m into the seabed using a 5t vibrating hammer, while sheet piles from the old quay wall were extracted, sold on and reused by another company.
In the process, the RNLI reclaimed a 4.3m stretch of land from the harbour to allow more space to manoeuvre lifeboats once the ALC is up and running.
Here Bam Nuttall offered up an alternative solution: rather than excavating the harbour silt and replacing it with an imported fill, which is expensive and would involve lorry journeys to bring in the material, it proposed using silt strengthening. This innovative technique involved mixing cement into the silt with specialist equipment to create an improved structural quality material that can be used for fill.
Creating a world class centre of excellence
Engineering excellence is in the blood at the RNLI. Unbeknown by most, the charity designs all its own lifeboats with its own team of naval architects using the latest technology to push the boundaries to improve lifesaving at sea while protecting volunteer crew.
The new facility will enable the RNLI to produce its own all-weather lifeboats in-house for the first time, as well as helping to retain lifeboat building and maintenance skills in the UK and, in the process, becoming a world class centre of engineering excellence.
The charity already builds all-weather lifeboat hulls and carries out all-weather lifeboat maintenance in-house. It has also been successfully producing and maintaining inshore lifeboats on the Isle of Wight for decades, and this will continue. The new facility is a logical next step for the charity.
Why? The RNLI has identified risks to its lifeboat building supply chain, as fewer suppliers have the ability to meet its specialist requirements, so it has less control over quality and cost.
As well as improving the quality of lifeboat building, the new facility will give the charity greater control over its lifeboat production and maintenance supply chain.
The first all-weather lifeboats to be built at the facility will be the newly designed Shannon class lifeboat which uses water-jet technology to create a highly manoeuvrable boat that can land on beaches.
The charity will need to build at least 50 Shannon class all-weather lifeboats at the new facility. During their operational lives, these 50 vessels are expected to rescue over 56,000 people and save an estimated 1,500 lives.
“That was a good saving that we shared with Bam Nuttall,” says Evans. “It is a good example of the collaborative approach we have had on the project.”
Raising the site by 1.4m demanded a lot of sand, and here too imports were avoided. A hefty 25,000t of sand was dredged from sandbanks in Poole Harbour and delivered to the site by barge. This avoided 2,500 lorry journeys in and out of Poole, reducing the RNLI’s costs, while also saving the Poole Harbour Commission future maintenance dredging costs.
The final element of Bam’s work was to build a new, wider slipway. A steel sheet pile cofferdam was installed to allow the concrete slabs of the new slipway to be constructed in dry conditions.
The enclosure was then purposely flooded so specialist divers could begin cutting away the excess height of the steel piles. Using underwater welding equipment, the divers then fitted over 200 cathodic protection anodes to the piles, prolonging the life of the steel piles by 20 years.
The work has already been tested in anger: the January 2014 storms, combined with exceptionally high tides, put the new sea walls to the test, and the site was well protected where previously it would have flooded in similar conditions.
“We had a storm surge back in January that would have overtopped the old quay walls. So raising the site has already proved to be the right thing to do,” notes Richings.
“We didn’t have to do it - we could have just raised the building. But sites around this one have already been raised, so this would have been the weak point in Poole for coastal defences, so raising the wall was theright thing to do.”
Lead designer: Ramboll
Ellis Belk Associates
RNLI Estates Office
Sea wall and ground works contractor: Bam Nuttall
Building contractor: Leadbitter
CDM co-ordinator: PH Warr
Work is now focused in the building itself. Bouygues subsidiary Leadbitter won the job in November 2013, and its first task was to prepare the ground.
The site is reclaimed land, and prior to the RNLI acquiring the site in 1974 it was a shipyard - and so contains a m ix of generally poor materials. A saturated peat layer just below that adds to the complexity.
All in all it’s not a good combination for carrying the weight of heavy lifeboats, so the front 30m of the site was surcharged, and 4,500 vertical band drains were installed to allow water to escape from the peat layer and speed up consolidation and settlement.
The surcharge was provided by the dredged fill material and recycled demolition materials, which were later spread to raise the general level of the site.
“We knew the layer of peat would make the ground settle, so we squeezed out as much moisture as possible with the surcharging and band drains, and got 250mm to 300mm settlement,” says Evans.
That was effective for the general site, but not good enough for the main building and courtyard area. Ground here has been improved by vibro concrete columns (VCC) that punch through the peat layer to firmer ground.
Leadbitter installed 2,094, 5m deep vibro columns in all as a ground stabilisation measure. A layer of sand in combination with a geotextile mat was then used to form a load transfer platform to cover the VCC piles and level off the site upon which reinforced concrete pad foundations were laid.
These concrete pad foundations - 50 in total and up to 360m3 in size - are what actually carry and spread the weight of the Ramboll-designed building’s steel frame.
That is now racing up, with the building itself due for completion this winter. Operations will be introduced in the first quarter of 2015, with the RNLI aiming to get the building fully operational by 2019.
- To find out more about the RNLI or to make a donation to the All-weather Lifeboat Centre project click here.
Creating a world class centre of excellence
The All-weather Lifeboat Centre (ALC) project has seen the RNLI using building information modelling (BIM) for the first time on a construction project.
“Initially the idea of using BIM was to enable a collaborative approach to design and for clash detection in construction, but it has since developed more into the facility management side,” explains RNLI ALC project supervisor Iona Evans.
The aim was to save time in the development process by making it easier for the design team to work together to produce an integrated design. BIM acts as a shared knowledge resource for information about the facility, which will form a reliable basis for decisions during its lifecycle, from earliest conception to demolition.
Using BIM has enabled the team to develop a new way of thinking and designing. All aspects of the build and everything that is going into the building are included within the BIM model. Each user can see a 3D virtual model of the building so it is easier for them to understand the design and to collaborate. Planning the fitting of mechanical and electrical components into the build is made easier by viewing in 3D.
But the real saving opportunity comes once the building is in use.
“Given the criticality of the building, you have got to look at the asset management potential of BIM,” says RNLI shoreworks construction manager Christopher Refoy. “So the idea of moving to a new level of facilities management developed.”
Critical to this enhanced use of BIM is an energy usage monitoring system, explains Evans. “This goes hand in hand with BIM and will allow us to count the cost of all processes carried out on the boats,” she says.