Aluminium, steel, marine timber and an assortment of composites are the materials in Quicksilver’s hull construction, but this bald statement barely scratches the surface of the story. Because it is how materials are used that really matters. This is the nub of it. Quicksilver is very strong and rigid, yet it is also lightweight for its size, engine power and speed potential. To design and build a structure that is very strong and rigid is easy. But designing a structure that is very strong and rigid and light is not. It should go without saying that if a boat is lightweight in relation to its power, it will accelerate faster and in a shorter distance. It will also decelerate faster, and in a shorter distance, and generally out-perform, a heavier craft of the same power output.
The desire to keep weight down is therefore easy to appreciate. But what about stiffness and strength? Why are they so important too?
Quicksilver’s hull structure – because it will move extremely fast – will be subjected to complex and immensely powerful dynamic forces. Those forces increase as the square of the speed. This means the stresses and strains at 200mph are four times greater than they are at 100mph. And at 400mph, the loadings become 16 times greater than at 100mph. In other words, the magnitude of the forces rises exponentially. A structure that is not strong enough would simply break under such colossal loads. And a structure that is not rigid enough, as it flexes excessively under the forces imposed upon it, would cause the angles of the boat’s points of contact with the water to alter erratically as it speeds along the lake, compromising its handling and stability.
Because Quicksilver is designed to travel faster than any machine has ever travelled on water before, it must have a hull design and construction well up to the job. Very strong, very rigid, but also lightweight for both its size and the forces it must cope with.
In the midst of all this, we generally are aiming to employ materials and construction methods which already have a proven track record in water-speed use – this, for reasons both of safety and affordability. That said, we have embraced opportunities to extend the existing experience-base in areas where we feel it offers sufficient performance gains, conducive with maintaining the high safety levels we demand. An example of this is the use of structural bonding techniques on Quicksilver.
The central section of the hull serves as the structural “backbone” of the boat. It consists of a spaceframe fabricated from high-tensile steel tubing, bearing fabricated aluminium upper-hull structures and clad in a combination of composite materials and structural foam which act in concert to increase overall strength and rigidity, bestow water-tightness, and create the curvaceous external shape of the craft.
In the image above, a large sheet of aluminium alloy has been laser-cut in a pre-programmed sequence to create the individual parts from which one of Quicksilver’s major internal structural components was fabricated. Much of the craft’s structure is aluminium alloy, but materials and methods of construction vary throughout the boat, according to the specific structural requirements in different regions.
For example, the entire stern section of Quicksilver is a unitary (monocoque) structure made of aluminium, and extensive use is made of bonding techniques rather than welding. Contrast this with the central section of the boat – with welding employed exclusively in the steel spaceframe, aluminium structures bolted on, and a marine timber and Kevlar cladding. The front section of the boat is constructed from aluminium, marine timber and Kevlar, carbonfibre and thermoformed structural foam, employing techniques not dissimilar to those used in conventional competition-craft and leisure-craft building.
Several companies have collaborated with the Quicksilver team in the hull build to date …
The high-tensile steel tubing for the hull spaceframe was made for Quicksilver with material supplied by British Steel/Corus.
The foundry, at Wednesfield, Wolverhampton was where the initial manufacturing process for Quicksilver’s hull spaceframe took place. It was the production of a “tube hollow”, the partially-formed expression in steel of a shape that would subsequently be drawn out into long, straight lengths of two-inch-square tubing (the two dramatic images above were taken in the very first moments that Quicksilver began to take physical form). This basic tube material was then transported the short distance south to tubemaking specialist Accles & Pollock at Oldbury for completion and emerged as 33 lengths of 16-gauge BSI T59 cold-drawn seamless tubing, each 20 feet long. Paul Rollason led the technical input by Accles & Pollock. Our thanks to him for the instrumental part he played.
Production of the tubing was a project landmark, in that it was the first demonstration that British industry would get behind the boat build. We gratefully acknowledge, to this day, the commitment shown by Corus/Tata Steel and Accles & Pollock at that early stage.
Quicksilver’s hull spaceframe design has been the product of two highly-experienced engineers. Glynne Bowsher was responsible for the bulk of the design, which allowed the initial phase of manufacturing to take place, then Roland Snell subsequently augmented Glynne’s work. Mention should also be made of the contribution by Mike Challenger of Haydndesign, who created a detailed 3D CAD model of the spaceframe, and to Elite Consulting, who undertook initial finite-element analysis (FEA) of the spaceframe and other major structural elements of the craft.
Special welding techniques were developed for us by BOC/Linde to fabricate the hull spaceframe, and were independently tested and certified by The Welding Institute in Cambridge. Welding, by the TIG method, was undertaken by a team of three of BOC’s top developmental specialists: Steve Moynihan, Chris Birch and Craig Rollinson. All three were seconded to the Quicksilver team by the BOC Gases Fabrication Technology Centre at Morden, in south-west London. Some years earlier, Steve Moynihan – pictured at centre in the photo above, taken as Quicksilver began taking shape – had participated in welding work on the spaceframe chassis of Richard Noble’s ThrustSSC supersonic car, which RAF Squadron Leader Andy Green drove to set the current World Land Speed Record of 763.035 mph in 1997.
When welding of Quicksilver’s hull spaceframe was completed, BOC’s team undertook non-destructive testing (NDT), using the dye-penetration method. This ensured that there were no flaws – hairline cracks, for example – in any of the welds.
For BOC’s far-sighted decision to participate in the Quicksilver project, we are deeply indebted to Dr. Duncan Yates, the late Dr. Wendy Peters, and business development manager Shaun Schofield.
Once in service, Quicksilver’s spaceframe will be kept permanently pressurised, thereby allowing rapid detection in the unlikely event of any cracks developing in the welded structure. Lightweight aluminium valves have been specially manufactured for us for this purpose by Oliver Valves of Knutsford, Cheshire. There is one valve for each ‘sector’ of the spaceframe, the structure being divided-up internally by airtight bulkheads, so that the location of any flaw, should it develop, can be more readily pinpointed. Pressurisation will be by means of an inert gas, which will double as a corrosion inhibitor.
The mountings which hold the Rolls-Royce Spey engine in Quicksilver’s hull were made for us by Radshape of Aston, Birmingham. These are a combination of all-new fabricated structures, all-new machined components, some adapted Buccaneer aircraft engine-mounting parts, and some standard Buccaneer engine-mounting parts. The two side (trunnion) engine mountings are manufactured in steel, while the rear (upper centreline) engine mounting, currently also in steel, is incorporated within a large hoop structure fabricated in high-performance 7020-T6 aluminium alloy. This hoop is seen at far right in the photo above.
Detailed design of a second hoop structure – which also has the ability to partially support the engine, if required – was duly undertaken, and its manufacture by Radshape in 6082-T6 aluminium alloy was completed in January 2012. This hoop, seen at centre in the photo above, is known as the trunnion hoop.
As well as their role in the engine-mounting scheme, both of these hoops make an important contribution to the overall strength and rigidity of the central portion of the main hull structure.
Credit for the design of the hoops and engine mountings goes to several engineers, including Roland Snell and Tim Harrison. We also gratefully acknowledge the contribution of Glynne Bowsher, who kindly undertook the early conceptual work on this aspect of Quicksilver’s design.
A third hoop, known as the intake hoop – situated forward of the engine-related hoops described above – was added to the boat in April 2013. A key function of this hoop is to serve as the upper mounting point for two bracing struts which will extend diagonally forwards and downwards from the top of the main hull to the tops of the sponsons. In addition, the intake hoop itself contributes further strength and rigidity to the hull structure, and will also serve as the aft mounting point for the engine air-intake module and the forward mounting point for the front engine cover. Radshape was, once again, the firm entrusted with manufacturing this hoop, which is an all-new design from the Quicksilver team.
We are much indebted to Nottinghamshire businessman Mich Stevenson OBE, whose property development company Spenbeck is a long-standing Quicksilver Corporate Club member, for sponsorship he specifically directed to advancing the craft’s upper-hull structure. Mich is a board member of Sport England and was a key figure in the regeneration of the historic area of Nottingham known as the Lace Market, which includes the National Ice Centre. The support of people such as Mich, alongside an army of devotees across the country, is making it possible to see that the dream of regaining the World Water Speed Record for Britain is well within reach.
In 2010 and 2012 we received assistance from the Transport iNet, which is part-funded by the European Regional Development Fund (ERDF). The Transport iNet brings innovative expertise together and helps eligible East Midlands enterprises – primarily small- and medium-sized – to thrive. Our progress on the upper-hull and forward section of Quicksilver was greatly expedited by this timely and much-valued aid.
Detailed design of the craft’s bow/foredeck/keel section is being led by Mark Evans, an engineer with considerable marine-structures experience. The manufacturing process for this section of the boat began in March 2013, when Trident Foams, of Furness Vale, High Peak, CNC-machined the mould for the foredeck outer panel. This mould then passed to the Nottingham premises of CC Composites, where the foredeck panel itself was made in April, using vacuum resin infusion. The deck is 17mm thick and has a sandwich construction comprising of two, triple-ply, carbonfibre twill skins encasing a core of Airex R63.80 structural foam that was thermoformed to the required 3D shape. The work was led by CCC’s Alex Barker, who has many years’ involvement in the manufacture of sailing-yacht hulls and competition rowing-boat hulls. Nigel Lowe and Joanna Ellis completed the experienced trio that manufactured the foredeck.
Many thanks to Alex, Nigel and Jo, and CCC’s owner, Kevin Riley; thanks also to Roger Barraclough and Jon Rotheram of Trident Foams, and Trident’s MD, Phil Kenyon. An acknowledgement, too, to Sheffield-based Fripp Design for assisting us with aspects of the foredeck detailed design task.
In the photograph above, the foredeck is pictured at a key stage in the manufacturing process. The carbonfibre plies and the Airex core layer have been laid-up in the mould, and a vacuum bag has been tailored tightly over it in preparation for liquid resin being drawn through the entire structure as part of the consolidation process. The Airex, a lightweight material manufactured by the Swiss-based 3A concern and marketed by Trident Foams, is 15mm thick and the carbonfibre skins are each 1mm thick – resulting in a 17mm-thick compound-curvature panel that is very stiff and strong for its weight. The completed foredeck panel is 2.35 metres long and constitutes the upper casing of Quicksilver’s bow section.
Construction of the rest of the bow structure started in June 2015. This could only get under way once further analysis and detailed design work had been done, and this took a considerable time. The team-members assigned to the bow build include Ed Lupton, Jeff White and Bill Woodhouse. Long-serving Quicksilver team-member Bill’s previous speed-record involvement was as leader of the British Airways Engineering team at Heathrow which built the tail surfaces of ThrustSSC.
The shape of Quicksilver’s hulls was conceived by the internationally-respected marine architect Lorne Campbell, working in close collaboration with the team’s aerodynamicist Mike Green. Lorne has contributed his expertise to the Quicksilver project at several key stages dispersed across a considerable period of time. We have, throughout, been most thankful for his input at these pivotal points in the boat’s development.